ccm/sff-papers · Datasets at Hugging Face

['Konig, Oliver', 'Fadel, Georges M.']

2019-03-12T16:41:02Z

1999

Mechanical Engineering

null

['https://hdl.handle.net/2152/73599', 'http://dx.doi.org/10.26153/tsw/741']

eng

1999 International Solid Freeform Fabrication Symposium

Open

['FE"\'analysis', 'DOF']

Application of Genetic Algorithms in the Design of Multi-Material Structures Manufactured in Rapid Prototyping

Conference paper

https://repositories.lib.utexas.edu//bitstreams/291ae70f-08c4-4f8d-b4c7-92faa047deea/download

null

Recent developments in the Rapid Prototyping technology establish it as a new manufacturing technique, enabling localized material addition to build a part. Thus, heterogeneous structures, consisting of more than one material can be produced. The aim of this paper is to present an optimization tool to find the best material distribution in a multi-material structure due to given objectives and constraints. The tool is based on genetic algorithms using a discrete material model and FE"'analysis to evaluate the objective functions. It can optimize the distribution materials in 2D-structures with up to 1500 DOF's at reasonable computational costs. Its performance is shown on a bi-objective optimization of a turbine blade.

null

['Ouyang, J.H.', 'Mei, H.', 'Valant, M.', 'Kovacevic, R.']

2019-10-22T18:00:05Z

2002

Mechanical Engineering

null

['https://hdl.handle.net/2152/76327', 'http://dx.doi.org/10.26153/tsw/3416']

eng

2002 International Solid Freeform Fabrication Symposium

Open

Welding

Application of Laser-Based Additive Manufacturing to Production of Tools for Friction Stir Welding

Conference paper

https://repositories.lib.utexas.edu//bitstreams/91806466-1b99-4271-88d2-92922407539c/download

null

This paper presents a feasibility study of application of laser-based additive manufacturing to production of tools for friction-stir welding (FSW) of materials. The design and rapid manufacturing of powerful tools has become one of the major challenges in expanding the application of FSW processes to new materials. The one-step laser cladding process is capable of creating a novel, fully dense and metallurgically bonded near-net-shape tool with microstructural and compositional gradients. In this paper, two kinds of FSW-tool materials are developed and evaluated for the applications of welding different materials. A pure H13 tool steel powder is used to build a FSW-tool for welding the materials with relatively low melting temperatures, such as aluminum alloys. A WC-based ceramet/tool steel functionally graded material (FGM) is synthesized to build a FSW-tool in order to weld the materials with higher melting temperatures and highly abrasive materials such as MMC materials. By controlling the amount of different supplied powders under the optimized laser cladding conditions, WC-based ceramet/tool steel FGMs are successfully synthesized layer by layer. FSW experiments are carried out to evaluate the deposited tools.

This work was financially supported by THECB, Grants 003613-0022-1999, 003613- 0016-2001, NSF Grants No. DMI-9732848 and DMI-9809198, and the U.S. Department of Education, Grant No. P200A80806-98.

null

['Malone, Evan', 'Purwin, Oliver']

2020-02-13T21:02:36Z

2004

Mechanical Engineering

null

['https://hdl.handle.net/2152/79979', 'http://dx.doi.org/10.26153/tsw/7004']

eng

2004 International Solid Freeform Fabrication Symposium

Open

viscosity

Application of Machine Learning Methods to the Open-Loop Control of a Freeform Fabrication System

Conference paper

https://repositories.lib.utexas.edu//bitstreams/d0605853-f5c0-4975-97fc-4e35567e1659/download

null

Freeform fabrication of complete functional devices requires the fabrication system to achieve well-controlled deposition of many materials with widely varying material properties. In a research setting, material preparation processes are not highly refined, causing batch property variation, and cost and time may prohibit accurate quantification of the relevant material properties, such as viscosity, elasticity, etc. for each batch. Closed-loop control based on the deposited material road is problematic due to the difficulty in non-contact measurement of the road geometry, so a labor-intensive calibration and open-loop control method is typically used. In the present work, k-Nearest Neighbor and Support Vector Machine (SVM) machine learning algorithms are applied to the problem of generating open-loop control parameters which produce desired deposited material road geometry from a description of a given material and tool configuration comprising a set of qualitative and quantitative attributes. Training data for the algorithms is generated in the course of ordinary use of the SFF system as the results of manual calibration of control parameters. Given the large instance space and the small training data set compiled thus far, the performance is quite promising, although still insufficient to allow complete automation of the calibration process. The SVM-based approach produces tolerable results when tested with materials not in the training data set. When control parameters produced by the learning algorithms are used as a starting point for manual calibration, significant operator time savings and material waste reduction may be achieved.

null

['Hasan, S.', 'Rennie, A.E.W.']

2021-09-23T22:45:10Z

2008

Mechanical Engineering

null

['https://hdl.handle.net/2152/88044', 'http://dx.doi.org/10.26153/tsw/14985']

eng

2008 International Solid Freeform Fabrication Symposium

Open

['Rapid Manufacturing', 'spare parts industry', 'e-business']

The Application of Rapid Manufacturing Technologies in the Spare Parts Industry

Conference paper

https://repositories.lib.utexas.edu//bitstreams/08d8f05a-05c0-4aa6-910e-7fa8aeec1020/download

null

text

null

['Bharadwaja, R.', 'Murugan, Aravind', 'Chen, Yitao', 'Liou, F W']

2021-11-18T18:26:50Z

2019

Mechanical Engineering

null

['https://hdl.handle.net/2152/90457', 'http://dx.doi.org/10.26153/tsw/17378']

eng

2019 International Solid Freeform Fabrication Symposium

Open

['schlieren', 'visualization', 'shielding gas', 'additive manufacturing']

Application of Schlieren Technique in Additive Manufacturing: A Review

Conference paper

https://repositories.lib.utexas.edu//bitstreams/c6765b25-515a-4723-8c53-66123153de35/download

University of Texas at Austin

Additive manufacturing has gained a lot of attention in the past few decades due to its significant advantages in terms of design freedom, lower lead time, and ability to produce complex shapes. One of the pivotal factors affecting the process stability and hence the part quality is the shielding gas flow in additive manufacturing. As extremely beneficial for the process, the shielding gas flow is often set at maximum supply to achieve enough gas cover over the substrate. This causes excessive quantity of shielding gas to be unutilized. Realizing the importance of shielding gas, various studies have been carried out to monitor and visualize the shielding gas, and one such technique is Schlieren imaging. Schlieren visualization has been used since the 1800s as a powerful visualization tool to visualize fluctuations in optical density. The Schlieren technique is highly effective for visualizing and optimizing shielding gas flow. This paper aims to provide an overview of Schlieren technique used for visualization of shielding gas and highlights the application of Schlieren in additive manufacturing.

null

['Harryson, Ola', 'Cormier, Denis', 'Marcellin-Little, Denis', 'Jaja, Ketan']

2019-10-22T17:36:22Z

2002

Mechanical Engineering

null

['https://hdl.handle.net/2152/76322', 'http://dx.doi.org/10.26153/tsw/3411']

eng

2002 International Solid Freeform Fabrication Symposium

Open

Preoperative Pllanning

Application of SFF to Preoperative Planning and Surgical Rehearsal for Treatment of Limb Deformities in Dogs

Conference paper

https://repositories.lib.utexas.edu//bitstreams/eeb250cc-9bf1-47b5-b400-9b79cae2bd1a/download

null

This report describes SFF-aided assessment and preoperative planning for treatment of bilateral multifocal pelvic limb deformities in a one-year old German Shepherd dog. CT scans were converted to solid models and stereolithography patterns were prototyped. RTV silicone molds were constructed and three sets of polyurethane patterns were cast for pre-surgical rehearsal. The paper compares traditional osteotomy planning procedures, planning via virtual prototypes, and planning with full-scale physical prototypes.

null

['Kinsella, M.E.', 'Lilly, B.W.', 'Bhagavatula, N.', 'Cooper, K.G.']

2019-10-22T18:07:57Z

2002

Mechanical Engineering

null

['https://hdl.handle.net/2152/76330', 'http://dx.doi.org/10.26153/tsw/3419']

eng

2002 International Solid Freeform Fabrication Symposium

Open

Quantities

Application of Solid Freeform Fabrication Processes for Injection Molding Low Production Quantities: Process Parameters and Ejection Force Requirements for SLS Inserts

Conference paper

https://repositories.lib.utexas.edu//bitstreams/8acf9c49-e28c-4c8b-8d95-d5068e419d12/download

null

Studies are underway for the application of solid freeform fabrication processes for mold inserts to be used in thermoplastic injection molding of low quantities of parts. This work initially compares a laser sintered insert (LaserForm™ ST-100) with a steel insert. Models and experiments determine process parameters, including molding latitude, and ejection force requirements. Ejection force predictions are based on work by Menges, using values for elastic modulus determined from tensile tests at ejection temperatures. Similar studies are planned for stereolithography inserts (SL 5170).

null

['Jayanthi, Suresh', 'Harwin, William', 'Keefe, Michael', 'Kumar, Vijay']

2018-11-02T16:16:03Z

1995

Mechanical Engineering

doi:10.15781/T21R6NK6M

http://hdl.handle.net/2152/69334

eng

1995 International Solid Freeform Fabrication Symposium

Open

['stereolithography', 'cerebral palsy', 'rehabilitation engineering']

Application of Stereolithography in the Fabrication of Rehabilitation Aids

Conference paper

https://repositories.lib.utexas.edu//bitstreams/e00c1557-6072-4ac7-aeaf-9b1265e927e3/download

null

Free form fabrication methods have a great potential to significantly improve the design and manufacture of equipment for people with physical disabilities, such as quadriplegia through spinal cord injury, arthrogryposis, or cerebral palsy. Depending on the nature of the disability a device may need to be designed or adapted. A person with quadriplegia, for example, may benefit from an assistive device that maps existing head movements, into the movements of a spoon between a plate and his/her mouth. To be comfortable and effective a person Iuay need a headband that can connect to a suitable linkage. Stereolithography lends itself well to the fabrication of such one-of-akind devices. Since the fabrication process time is considerably less than conventional approaches a greater number of iterations can be performed during the design to arrive at the most compatible device for a particular disability. Some rehabilitation devices are fabricated to establish the viability and linlitations of this approach. This paper details the efforts underway to integrate stereolithography with the needs of rehabilitation engineering.

null

['Fisher, Joseph W.', 'Simpson, Timothy W.', 'Miller, Simon W.']

2023-03-01T17:15:32Z

2022

Mechanical Engineering

null

['https://hdl.handle.net/2152/117548', 'http://dx.doi.org/10.26153/tsw/44428']

eng

2022 International Solid Freeform Fabrication Symposium

Open

Lattice Structure

Application of Systems Engineering to Lattice Structure Design: A Framework for Requirements Flow Down

Conference paper

https://repositories.lib.utexas.edu//bitstreams/2516141b-ebf3-47e3-aa00-bc4446fccb65/download

null

In the field of additive manufacturing, highly ordered cellular structures with repeating patterns in space, known as lattice structures or simply “lattices”, have been shown to sig- nificantly improve the performance per unit mass of engineered components compared to traditionally machined designs. The characteristics of these lattices are dependent on many design decisions, leading to challenges in determining how to best utilize them. This issue is further complicated when the density, size, and topology of the lattice can spatially vary in the design domain. Many methods have been proposed to optimally distribute material within a lattice structure; however, these methods exist in a bubble, independent of broader engineering design criteria and processes. In this paper, we introduce a framework based on systems engineering to guide the design of lattice structures using the component requirements as inputs and outputting a verified and validated design based on those requirements. The framework translates component requirements down to the lattice structure and provides a means to verify and validate that the final design meets those requirements. We provide a walk-through of the framework by designing a lattice structure for an oil and gas component, and discuss future research to extend, verify, and validate the framework.

null

['Adnan, Muhammad', 'Lu, Yan', 'Jones, Al', 'Cheng, Fan Tien']

2021-11-16T16:25:11Z

2019

Mechanical Engineering

null

['https://hdl.handle.net/2152/90334', 'http://dx.doi.org/10.26153/tsw/17255']

eng

2019 International Solid Freeform Fabrication Symposium

Open

['additive manufacturing', 'fog computing', 'monitoring & control', 'functional architecture', 'control architecture', 'data analytics']

Application of the Fog Computing Paradigm to Additive Manufacturing Process Monitoring and Control

Conference paper

https://repositories.lib.utexas.edu//bitstreams/2d04ea32-cba5-4730-ba23-e3603beabaf8/download

University of Texas at Austin

Monitoring and controlling Additive Manufacturing (AM) processes play a critical role in enabling the production of quality parts. AM processes generate large volumes of structured and unstructured in-situ measurement data. The ability to analyze this volume and variety of data in real-time is necessary for effective closed-loop control and decision-making. Existing control architectures are unable to handle this level of data volume and speed. This paper investigates the functional and computational requirements for real-time closed-loop AM process control. The paper uses those requirements to propose a function architecture for AM process monitoring and control. That architecture leads to a fog-computing solution to address the big data and real-time control challenges.

null

['Chahine, Gilbert', 'Smith, Pauline', 'Kovacevic, Radovan']

2021-09-30T19:14:49Z

2010

Mechanical Engineering

null

['https://hdl.handle.net/2152/88284', 'http://dx.doi.org/10.26153/tsw/15225']

eng

2010 International Solid Freeform Fabrication Symposium

Open

['topology optimization', 'modern additive manufacturing', 'Electron Beam Melting', 'functionally graded porosity', 'bio-adaptable dental implants']

Application of Topology Optimization in Modern Additive Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/350d3d4c-51e8-48a0-9556-0af9dbbf25e7/download

University of Texas at Austin

The current work examines the principle of topology optimization (TOP) and solving the problem of minimal compliance, and its applications in modern additive manufacturing (AM). The theory of TOP has been excessively investigated for the past few decades; however its practical use is hindered by manufacturing limitations of manifesting the designs into physical parts. TOP numerically determines the favorable topology configuration contained in a workspace that is constrained by a specific set of external supports and applied loads. It overcomes conventional design traditions, and solves for finding the path of least resistance, mimicking phenomenon found in natural structures, such as bone and wood. The present research focuses on the different methodologies invested in the field, and also inspects the possibilities and efficiency of using numerical design, which is powered by TOP, in modern AM processes such as Electron Beam Melting enabling the production of highly complex parts. The major interest is the production of functionally graded porosity (FGP) in bio-adaptable dental implants able to reduce stress shielding, promote faster osseointegration, and provide micromotion between the dental prosthesis and the root form of the implant. Future implications of the field include optimized porous structures aiming towards application-defined stiffness and pore size, enabling a digital design with advances analogous to modern AM.

null

Winkelman, Wayne

2018-10-03T16:45:46Z

1994

Mechanical Engineering

doi:10.15781/T2V11W50J

http://hdl.handle.net/2152/68663

eng

1994 International Solid Freeform Fabrication Symposium

Open

['CAD/CAM', '3D digitized data', 'reverse engineering']

Applications of 3D Laser Digitizing and Surfacing Technologies

Conference paper

https://repositories.lib.utexas.edu//bitstreams/9ad3ba3c-d02a-4c16-ae04-e78b0e77fd73/download

null

['Mohammed, Mazher I.', 'Tatineni, Joseph', 'Cadd, Brenton', 'Peart, Greg', 'Gibson, Ian']

2021-10-28T21:43:23Z

2016

Mechanical Engineering

null

https://hdl.handle.net/2152/89708

eng

2016 International Solid Freeform Fabrication Symposium

Open

['prosthesis', '3D printing', 'modelling', 'multi-material', 'soft tissue']

Applications of 3D Topography Scanning and Multi-Material Additive Manufacturing for Facial Prosthesis Development and Production

Conference paper

https://repositories.lib.utexas.edu//bitstreams/e7c23dcc-8e62-4c68-9caf-737904a6565e/download

University of Texas at Austin

Prosthetic based rehabilitation offers several advantages over surgical intervention, however, devices are generally handmade using labour intensive and subjective manufacturing techniques. We investigate the use of optical scanning to capture the surface topography from a volunteer’s facial anatomy, reconstruct this into a 3D CAD model, and from that design a patient specific prosthesis. This approach offers many advantages over existing techniques as data collection is non-intrusive, rapid and provides anatomically precise information. A CAD approach affords greater flexibility when evaluating design iterations and allows for the creation of ‘parts libraries’ for use with patients with no initial reference anatomy. The final prosthesis is realised through high resolution, multi-material 3D printing for precise model reproduction and to add functionalities such as mimicry of soft and hard tissues. Ultimately, we believe our approach provides an optimised, low-cost approach for streamlining the complete methodology for prosthesis production.

null

['Liou, Frank', 'Slattery, Kevin', 'Kinsella, Mary', 'Newkirk, Joseph', 'Chou, Hsin-Nan', 'Landers, Robert']

2020-02-27T19:14:59Z

2006

Mechanical Engineering

null

['https://hdl.handle.net/2152/80092', 'http://dx.doi.org/10.26153/tsw/7113']

eng

2006 International Solid Freeform Fabrication Symposium

Open

Rapid Prototyping

Applications of a Hybrid Manufacturing Process for Fabrication and Repair of Metallic Structures

Conference paper

https://repositories.lib.utexas.edu//bitstreams/adef9ef7-1ac2-4e5b-926b-c9b17f714025/download

null

Since its appearance, rapid prototyping technology has been of interest to various industries that are looking for a process to produce/build a part directly from a CAD model in a short time. Among them, the direct metal deposition process is the only process which directly manufactures a fully dense metal part without intermediate steps. However, challenges of the direct metal deposition process include building overhang structures, producing precision surfaces, and making parts with complex structures. Coupled between the additive and the subtractive processes into a single workstation, the integrated process, or hybrid process, can produce a metal part with machining accuracy and surface finish. Therefore, the hybrid process is potentially a very competitive process to fabricate and repair metallic structures. This paper summarizes the current development of the hybrid process to process high temperature metallic materials, including tool steel and Ti64. Research in simulation and modeling, process development, and actual part building and repair are discussed.

null

['Isanaka, Sriram Praneeth', 'Liou, Frank']

2021-10-05T19:23:30Z

2012

Mechanical Engineering

null

['https://hdl.handle.net/2152/88416', 'http://dx.doi.org/10.26153/tsw/15355']

eng

2012 International Solid Freeform Fabrication Symposium

Open

['Cyber Enabled Manufacturing', 'additive manufacturing technology', 'cyber-physical systems']

The Applications of Additive Manufacturing Technologies in Cyber-Enabled Manufacturing Systems

Conference paper

https://repositories.lib.utexas.edu//bitstreams/0cc996d3-09c5-422f-b222-c811d46fe2dc/download

University of Texas at Austin

The application of networked sensors and control in various areas, such as smart grids and infrastructures, has become a recent trend, called cyber-physical systems. The Cyber Enabled Manufacturing (CEM) environment is to apply these technologies in manufacturing systems to handle a significantly greater magnitude of manufacturing data. Additive manufacturing techniques print or place material layer by layer to form a part, thus have a great potential to help accelerate CEM process by printing or embedding sensors and actuators in the proper locations. This paper summarizes the roles of additive manufacturing technologies to help establish a CEM environment.

null

['Wohlert, Martin', 'Bourell, David L.', 'Das, Suman', 'Beaman, Joseph J.']

2019-09-23T15:19:57Z

2000

Mechanical Engineering

null

['https://hdl.handle.net/2152/75933', 'http://dx.doi.org/10.26153/tsw/3032']

eng

2000 International Solid Freeform Fabrication Symposium

Open

Densification

Applications of Powder Densification Maps to Direct Metal SLS/HIP Processing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/7a26921d-94f6-431e-9cad-8e900e9b5ba9/download

null

Recent investigations have shown that Direct Selective Laser Sintering in conjunction with Hot Isostatic Pressing (HIP) is capable of producing fully dense, near net shape, high performance metal components. A key aspect of this combined processing method is the selection of appropriate HIP process parameters to obtain full density parts. Powder Densification Maps provide a powerful tool for predicting the effect of time, temperature, pressure, and material properties on part density. This paper summarizes developments in Powder Densification Map production for Ti-6Al-4V and Inconel 625 materials. A comparison of theoretically predicted and experimentally determined densities for a variety of processing conditions is presented.

null

['Thomas, J.P.', 'Bender, B.A.', 'Pique, A.', 'Cooper, K.P.', 'Rayne, R.J.', 'Richardson, A.C.']

2019-10-18T17:07:55Z

2001

Mechanical Engineering

null

['https://hdl.handle.net/2152/76264', 'http://dx.doi.org/10.26153/tsw/3353']

eng

2001 International Solid Freeform Fabrication Symposium

Open

Fabrication

Applications of Solid Freeform Fabrication at the Naval Research Laboratory

Conference paper

https://repositories.lib.utexas.edu//bitstreams/efeacd08-1d4d-4e9f-b064-b1ae3ab37769/download

null

Solid Freeform Fabrication (SFF) and related techniques are used at the Naval Research Laboratory (NRL) for a variety of materials related investigations. Research and applications conducted over the past few years are described including: Helisys Laminated Object Manufacturing System (LOMS) fabrication of: ceramic piezoelectric actuators, tooling for multifunctional materials, and anatomical prototypes for surgical visualization; fabrication of mesoscale electronic and sensor components using a laser forward transfer direct write technique; and visualization of complex, 3-D microstructures using a Stratasys Fused-Deposition Modeler. The paper closes with a brief overview of future SFF related work at the NRL.

Support for this work from DARPA, Office of Naval Research, and the Naval Research Laboratory Core Research Program is gratefully acknowledged.

null

['Joshi, M.S.', 'Flood, A.', 'Sparks, T.', 'Liou, F.W.']

2021-11-16T16:17:50Z

2019

Mechanical Engineering

null

['https://hdl.handle.net/2152/90331', 'http://dx.doi.org/10.26153/tsw/17252']

eng

2019 International Solid Freeform Fabrication Symposium

Open

['supervised learning algorithms', 'support vector machines', 'random forests', 'machine learning', 'additive manufacturing']

Applications of Supervised Machine Learning Algorithms in Additive Manufacturing: A Review

Conference paper

https://repositories.lib.utexas.edu//bitstreams/a5e84fc3-f039-4f3d-8f2c-503624c84bdd/download

University of Texas at Austin

Additive Manufacturing (AM) simplifies the fabrication of complex geometries. Its scope has rapidly expanded from the fabrication of pre-production visualization models to the manufacturing of end use parts driving the need for better part quality assurance in the additively manufactured parts. Machine learning (ML) is one of the promising techniques that can be used to achieve this goal. Current research in this field includes the use of supervised and unsupervised ML algorithms for quality control and prediction of mechanical properties of AM parts. This paper explores the applications of supervised learning algorithms - Support Vector Machines and Random Forests. Support vector machines provide high accuracy in classifying the data and is used to decide whether the final parts have the desired properties. Random Forests consist of an ensemble of decision trees capable of both classification and regression. This paper reviews the implementation of both algorithms and analyzes the research carried out on their applications in AM.

null

['Wang, Jia-Chang', 'Dommati, Hitesh']

2021-11-08T23:06:34Z

2017

Mechanical Engineering

null

['https://hdl.handle.net/2152/90071', 'http://dx.doi.org/10.26153/tsw/16992']

eng

2017 International Solid Freeform Fabrication Symposium

Open

['slurry based stereolithography', 'high performance ceramics', 'non-self-supporting structures', 'earrings']

Applied Solvent-Based Slurry Stereolithography Process to Fabricate High-Performance Ceramic Earrings with Exquisite Details

Conference paper

https://repositories.lib.utexas.edu//bitstreams/b0feaeeb-9f43-4a34-9880-c01327f0149b/download

University of Texas at Austin

This paper discusses the application of Slurry based Stereolithography additive manufacturing process in the fabrication of complex earring models without any support structures requirement, using High-Performance Ceramic (HPC) materials. The earring model chosen in this study is a Rose flower with blossomed petals. The petals have edge thickness in microns and extreme overhangs with a custom text and logo on the bottom. Using any other ceramic additive manufacturing process, it requires support structures to build this model. The support removal in such minute structures is not easy and not always successful. Using Solvent based Slurry Stereolithography (3S) process, models with the micron details and overhangs can be easily built. This is enabling the neat and clean post-processing procedure to maintain the exquisite details and also gain high surface quality. The ceramic material used in this application is alumina. With some additives, it will show in different colors like sapphire. The resultant flowers are vividly shown in white, pink, green, and blue. In this study, it is also discussed about the slurry process, Stereolithography system, and proven applications of the 3S process.

null

['Emery, B.', 'Revier, D.L.', 'Lipton, J.I.']

2021-11-30T22:29:11Z

2021

Mechanical Engineering

null

['https://hdl.handle.net/2152/90571', 'http://dx.doi.org/10.26153/tsw/17490']

eng

2021 International Solid Freeform Fabrication Symposium

Open

['foams', 'viscous thread instability', 'viscous thread printing', 'cellular structures']

Applied Viscous Thread Instability for Manufacturing 3D Printed Foams

Conference paper

https://repositories.lib.utexas.edu//bitstreams/68ca81b3-d9cc-45a1-98be-9ecaf4b86819/download

University of Texas at Austin

Traditional foams are fabricated via stochastic chemical processes that yield homogeneous material properties. Foams can exhibit a wide range of material properties by varying process controls allowing them to be used in many industrial and commercial applications. Previously, additive manufacturing could only produce foam approximations in the form of traditional lattice infill. Our work employs viscous thread printing (VTP) of thermoplastic polyurethane (TPU) on a fused filament fabrication (FFF) printer, exploiting the semi-viscous nature of extruded filament to coil producing a new type of printed foam. Specimens were tested under compression to determine uniformity along principal axes and behavior under strain when compared to infill patterns, such as grid and cubic. This work establishes that VTP as applied to TPU can be used to manufacture programmable stiffness foams as a function of density, suited to a variety of needs and should be considered as an alternative to traditional foams and other printed lattice geometries.

null

['Chiu, Y. Y.', 'Chang, J. H.']

2020-02-17T14:30:03Z

2004

Mechanical Engineering

null

['https://hdl.handle.net/2152/79998', 'http://dx.doi.org/10.26153/tsw/7023']

eng

2004 International Solid Freeform Fabrication Symposium

Open

rapid prototyping

The Approach of Complex Insert Packaging Fabrication in Stereolithography

Conference paper

https://repositories.lib.utexas.edu//bitstreams/d7975c96-ac7d-43e9-bba2-e52ad356cffd/download

null

The approach of complex insert packaging fabrication in stereolithography is studied in the paper. There are many difficulties being overcome, such as the dispensing shadowing problem caused by the geometric shape of insert, the polymer feeding problem caused by greater insert height than the layer thickness, and the positioning problem of insert that leads to instability of packaging. These drawbacks led to unsatisfactory results of the insert packaging in stereolithography. In order to solve the problems, a new method of complex inserts packaging fabrication in stereolithography is proposed in this paper. Based on the geometric information, function and assembly direction of the inserts, the packaging approach is developed. The approach proposed in this paper has been verified by experiments. It brings considerable contributions to the application of insert packaging in stereolithography. It is also favorable to the improvement of insert packaging efficiency and assembly fabrication

null

['Tarasova, A.', 'Wegner, A.', 'Witt, G.']

2021-11-18T02:19:44Z

2019

Mechanical Engineering

null

['https://hdl.handle.net/2152/90412', 'http://dx.doi.org/10.26153/tsw/17333']

eng

2019 International Solid Freeform Fabrication Symposium

Open

['maximum filler volume packing fraction', 'laser sintering', 'polymers', 'reinforcement', 'fillers', 'additive manufacturing']

Approach to Defining the Maximum Filler Packing Volume Fraction in Laser Sintering on the Example of Aluminum-Filled Polyamide 12

Conference paper

https://repositories.lib.utexas.edu//bitstreams/015c75c0-0de2-45a0-9561-a6e002ccde38/download

University of Texas at Austin

Laser sintering is one of the most popular additive manufacturing techniques that uses thermoplastic polymer powders to generate layer-by-layer complex structures. Despite its broad application, some limitations exist restricting its further development. One such restriction is a narrow assortment of commercially available materials that would allow the production of the parts with the desired mechanical characteristics, which is the case with the widely used Polyamide 12 (PA12). Reinforcement of a matrix polymer with metal particles is routinely performed to achieve better mechanical properties. In this work, a PA12 system enhanced with a 35% volume ratio of aluminum was investigated. Mechanical characteristics, e.g. elastic and flexural moduli, were examined with respect to variation of manufacturing process parameters. In addition, a new methodology was tested, which should help determine the maximum filler packing volume fraction corresponding to the highest mechanical characteristics of a polymer-filler mixture.

null

['Rivette, M.', 'Mognol, P.', 'Hascoet, JY.']

2020-03-05T18:51:28Z

2006

Mechanical Engineering

null

['https://hdl.handle.net/2152/80142', 'http://dx.doi.org/10.26153/tsw/7163']

eng

2006 International Solid Freeform Fabrication Symposium

Open

Rapid Prototyping

Approach Tolerance in the Assemblies of Evolutionary Hybrid Prototypes

Conference paper

https://repositories.lib.utexas.edu//bitstreams/7662fd9c-f37f-475c-b6e6-4a6f6da644ae/download

null

A new answer is proposed to replace the traditional “one shot” prototype (manufactured in one piece with one process): the hybrid rapid prototype. It is used to highly reduce time, cost and increase reactivity during the development times of new products. The part is decomposed in several components which can quickly be changed and can be manufactured with a process the most adapted. The main objective of the presented method is to propose an available technological assembly between the different components of the part in the respect of technological and topological function, and initial tolerance. Using a graph of representation, fuzzy logic and a tolerance point of view, some entities are associated with a CIA (Assembly Identity Card) in accordance with evolutionary and manufacturing analysis. This work will be illustrated by an industrial tooling for plastic injection.

null

['Dreifus, G.D.', 'Jin, Y.', 'Ally, N.', 'Post, B.K.']

2021-11-01T20:40:58Z

2016

Mechanical Engineering

null

https://hdl.handle.net/2152/89739

eng

2016 International Solid Freeform Fabrication Symposium

Open

['geometric restrictions', 'big area additive manufacturing', 'fused deposition modeling', 'additive manufacture']

Approaches to Geometric Data Analysis on Big Area Additively Manufactured (BAAM) Parts

Conference paper

https://repositories.lib.utexas.edu//bitstreams/916f64eb-e52a-45a9-aba3-3216012551c1/download

University of Texas at Austin

The promise of additive manufacturing is that a user can design and print complex geometries that are very difficult, if not impossible, to machine. The capabilities of 3D printing are restricted by a number of factors, including properties of the build material, time constraints, and geometric design restrictions. In this paper, a thorough accounting and study of the geometric restrictions that exist in the current iteration of additive manufacturing (AM) fused deposition modeling (FDM) technologies on a large scale are discussed. Offline and online methodologies for collecting data sets for qualitative analysis of large scale AM, in particular Oak Ridge National Laboratory’s (ORNL) big area additive manufacturing (BAAM) system, are summarized. In doing so, a survey of tools for designers and software developers is provided. In particular, strategies in which geometric data can be used as training sets for smarter AM technologies in the future are explained.

null

['Lao, Wenxin', 'Li, Mingyang', 'Masia, Lorenzo', 'Tan, Ming Jen']

2021-11-08T22:34:42Z

2017

Mechanical Engineering

null

['https://hdl.handle.net/2152/90058', 'http://dx.doi.org/10.26153/tsw/16979']

eng

2017 International Solid Freeform Fabrication Symposium

Open

['rectangular extrudate', 'nozzle design', '3D printing for building and construction', 'extrusion based 3D printing']

Approaching Rectangular Extrudate in 3D Printing for Building and Construction by Experimental Iteration of Nozzle Design

Conference paper

https://repositories.lib.utexas.edu//bitstreams/608f8abe-dd66-4683-b77a-ea49ef0abf48/download

University of Texas at Austin

In Extrusion based 3D Printing technology, the voids could be reduced and the surface finish of printed parts could be improved with extrudate shape optimization. For large-scale 3D Printing technology like 3D Printing for Building and Construction, reducing printed layer height would increase the fabrication time drastically, while having few effect on voids reduction and surface finish improvement. In this paper, an iterative experimental approach to achieve the optimized nozzle design for rectangular shaped extrudate was proposed. Two nozzle prototypes were manufactured by Fused Deposition Method and implemented for experimental tests, then a new nozzle design was created based on the experimental extrudate shapes. This process iterated until a good rectangular extrudate shape was obtained. Printing tests were conducted with the optimized nozzle, which showed the designed nozzle could help to eliminate the voids among the printed parts and guarantee good surface finish without losing the speed of printing.

null

['Mason, Michael S.', 'Huang, Tieshu', 'Landers, Robert G.', 'Leu, Ming C.', 'Hilmas, Gregory E.', 'Hayes, Michael W.']

2020-03-09T14:07:39Z

9/4/07

Mechanical Engineering

null

['https://hdl.handle.net/2152/80180', 'http://dx.doi.org/10.26153/tsw/7199']

eng

2007 International Solid Freeform Fabrication Symposium

Open

Aqueous-Based Extrusion Fabrication

Aqueous-Based Extrusion Fabrication of Ceramics on Demand

Conference paper

https://repositories.lib.utexas.edu//bitstreams/38bfdf1c-5680-4788-83a8-7442207e2589/download

null

Aqueous-Based Extrusion Fabrication is an additive manufacturing technique that extrudes ceramic slurries of high solids loading layer by layer for part fabrication. The material reservoir in a previously developed system has been modified to allow for starting and stopping of the extrusion process on demand. Design pros and cons are examined and a comparison between two material reservoir designs is made. Tests are conducted to determine the optimal deposition parameters for starting and stopping the extrudate on demand. The collected test data is used for the development of a deposition strategy that improves material deposition consistency, including reduced material buildup at sharp corners. Example parts are fabricated using the deposition strategy and hardware design.

null

['Delfs, P.', 'Schmid, H.-J.']

2021-11-08T22:37:43Z

2017

Mechanical Engineering

null

['https://hdl.handle.net/2152/90059', 'http://dx.doi.org/10.26153/tsw/16980']

eng

2017 International Solid Freeform Fabrication Symposium

Open

['process parameters', 'laser sintered parts', 'surface roughness', 'laser sintering']

Areal Surface Characterization of Laser Sintered Parts for Various Process Parameters

Conference paper

https://repositories.lib.utexas.edu//bitstreams/9a57f82c-d39b-4fa7-a6bf-1fa556d56926/download

University of Texas at Austin

Laser sintered polymer parts consist of rough surfaces due to the layered manufacturing and adherence of incomplete molten particles. The absolute roughness depend on various process parameters like build angle, spatial position, build temperature, exposure order and layer time. Analyses with the help of several areal roughness values of DIN EN ISO 25178-2 considering these parameters are introduced in this paper. Multiple build jobs with 120 µm layer thickness and PA2200 powder were built on an EOS P396 machine using the same build job design with varying process parameters. An individual sample part was designed to receive lots of surface topography information with optical 3D measurements. The results show roughness dependencies for 0° to 180° build angles in 15° steps and eleven distributed in-plane and three axial direction positions depending on different build temperatures, reversed exposure order and layer times. Limitations of the varied parameters are finally derived for the manufacturing of improved surface qualities.

null

['Razdan, Anshuman', 'Henderson, Mark R.', 'Collins, Dan']

2019-02-19T20:28:07Z

1998

Mechanical Engineering

null

['https://hdl.handle.net/2152/73445', 'http://dx.doi.org/10.26153/tsw/597']

eng

1998 International Solid Freeform Fabrication Symposium

Open

['PRISM', 'Anthropology']

Art to Engineering: Pervasive RP activities at Arizona State University

Conference paper

https://repositories.lib.utexas.edu//bitstreams/dd3623a9-9a28-4363-9cc9-5e91b2b3913f/download

null

We present a sampling ofwidely diverse Rapid Prototyping activities at ASU. Through the interdisciplinary PRISM project, RP is firmly involved in three areas: education, research and outreach. Two courses have been developed, one teaches RP over the web and the other Visualization and RP as applied technologies aimed at interdisciplinary graduates and seniors. Researchers and students from Engineering, Architecture and Industrial Design, Fine Arts and Liberal Arts and Sciences and Business actively use RP. A recent formation ofthe PARfC (PRISM Advanced Rapid-fabrication Consortium) Consortium with local industry will create a local and formal center for research, education, service and training in Rapid Fabrication.

null

['Stavroulakis, P.', 'Davies, O.', 'Tzimiropoulos, G.', 'Leach, R.K.']

2021-11-09T14:54:28Z

2018

Mechanical Engineering

null

['https://hdl.handle.net/2152/90087', 'http://dx.doi.org/10.26153/tsw/17008']

eng

2018 International Solid Freeform Fabrication Symposium

Open

['artificial intelligence', 'data fusion', 'photogrammetry', 'fringe projection', 'deflectometry', 'segmentation network']

Artificial Intelligence-Enhanced Mutli-Material Form Measurement for Additive Materials

Conference paper

https://repositories.lib.utexas.edu//bitstreams/6efe19f6-3225-4e23-9852-1405e9892be6/download

University of Texas at Austin

The range of materials used in additive manufacturing (AM) is ever growing nowadays. This puts pressure on post-process optical non-contact form measurement systems as different system architectures work most effectively with different types of materials and surface finishes. In this work, a data-driven artificial intelligence (AI) approach is used to recognise the material of a measured object and to fuse the measurements taken from three optical form measurement techniques to improve system performance compared to using each technique individually. More specifically, we present a form measurement system which uses AI and machine vision to enable the efficient combination of fringe projection, photogrammetry and deflectometry. The system has a target maximum permissible error of 50 μm and the prototype demonstrates the ability to measure complex geometries of AM objects, with a maximum size of (10 × 10 × 10) cm, with minimal user input.

null

Gibson, I.

2021-10-05T15:46:10Z

2012

Mechanical Engineering

null

['https://hdl.handle.net/2152/88396', 'http://dx.doi.org/10.26153/tsw/15335']

eng

2012 International Solid Freeform Fabrication Symposium

Open

['Additive Manufacturing', 'Rapid Prototyping']

Ask Not What Additive Manufacturing Can Do For You...

Conference paper

https://repositories.lib.utexas.edu//bitstreams/b319e394-28bb-4251-b449-faf06b176d02/download

University of Texas at Austin

The paraphrase of John F Kennedy’s famous words is for 2 purposes. Firstly it is to acknowledge that there are some people who have considered that it is a major part of their life’s work to promote Additive Manufacturing (AM) technology as primarily a selfless act. AM comprises an outstanding range of technology that should be brought to public attention as a true revolution in how we design and manufacture products. The second purpose is to show that technology development is only one part of this promotion process and that there are other ways in which we can get involved. This paper describes the author’s journey over the (approximately) 20 years since he was introduced to what was then called Rapid Prototyping (RP). It is not a catalogue of research and development projects but rather a list of activities that he has been involved in to help promote and support AM technology over these years. It will describe the conferences, activities, associations and publications that have been created to allow academics and professionals to describe and discuss their work amongst themselves and to the larger society.

null

['Deng, Dongping', 'Chen, Yong']

2021-10-07T17:32:07Z

2013

Mechanical Engineering

null

['https://hdl.handle.net/2152/88489', 'http://dx.doi.org/10.26153/tsw/15423']

eng

2013 International Solid Freeform Fabrication Symposium

Open

['additive manufacturing', 'in-situ assembly', 'thin-shell structure', 'origami design', 'folding', 'fabrication speed']

Assembled Additive Manufacturing – A Hybrid Fabrication Process Inspired by Origami Design

Conference paper

https://repositories.lib.utexas.edu//bitstreams/507c9518-c8e8-4060-a218-539ca9cd8c03/download

University of Texas at Austin

Inspired by the recent developments on origami structures, we investigated a fast AM process for fabricating prototype models of thin-shell shapes. By combining the origami design and the additive manufacturing technology, a new fabrication process named Assembled Additive Manufacturing (AAM) is developed. In the process, a digital model is first analyzed to determine geometries that are fabricated by the layer-based and origami-based approaches. The thin shell model for the origami-based approach is then unfolded into a foldable 2D sheet. After the fabrication and folding of the 2D sheet, a postprocessing process is developed before the final prototype is fabricated using the layer-based fabrication process. Algorithms of analyzing and unfolding polygonal model and the details of the process are introduced in the paper; design parameters, mechanics analysis and test cases are also discussed.

null

['Telenko, Cassandra', 'Seepersad, Carolyn Conner']

2021-09-30T14:37:38Z

2010

Mechanical Engineering

null

['https://hdl.handle.net/2152/88258', 'http://dx.doi.org/10.26153/tsw/15199']

eng

2010 International Solid Freeform Fabrication Symposium

Open

['Selective Laser Sintering', 'Rapid Manufacturing', 'life-cycle', 'nylon powder material', 'material properties', 'environmental effects']

Assessing Energy Requirements and Material Flows of Selective Laser Sintering of Nylon Parts

Conference paper

https://repositories.lib.utexas.edu//bitstreams/f6bc4c52-736c-42ff-8033-fbbc2aeab1af/download

University of Texas at Austin

Selective laser sintering (SLS) is a prominent technology for rapid manufacturing (RM) of functional parts. SLS and competitive RM technologies are generally assumed to be more environmentally sustainable than conventional manufacturing methods because the additive process minimizes tooling, material waste, and chemical fluids. A thorough life cycle analysis (LCA) of the environmental impacts of SLS has yet to be published. This study focuses on a section of the SLS part life-cycle. It tracks the nylon powder material flows from the extraction and synthesis of the material to SLS part production. Basic material properties and environmental effects are reported. Estimates of material waste and energy use are also reported and compared with those of injection molding.

null

['Cloots, M.', 'Spierings, A.B.', 'Wegener, K.']

2021-10-11T21:45:39Z

8/16/13

Mechanical Engineering

null

['https://hdl.handle.net/2152/88654', 'http://dx.doi.org/10.26153/tsw/15588']

eng

2013 International Solid Freeform Fabrication Symposium

Open

['selective laser melting', 'SLM', 'metal parts', 'support structures', 'overhanging surfaces', 'support minimization', 'process heat', 'geometrical distortions', 'additive manufacturing']

Assessing New Support Minimizing Strategies for the Additive Manufacturing Technology SLM

Conference paper

https://repositories.lib.utexas.edu//bitstreams/67b73d0a-7b05-4b89-87c7-cc7d2f9f6e15/download

University of Texas at Austin

To successfully produce metal parts by SLM, additional support structures are needed to support overhanging surfaces in order to dissipate process heat and to minimize geometrical distortions induced by internal stresses. These structures are often massive and require additional post-processing time for their removal. A minimization of the extent to which support structures are needed would therefore significantly reduce manufacturing and finishing efforts and costs. A specific component segmentation strategy is developed. It allows the segmentation of critical areas of the component by applying a specific scanning strategy with appropriate energy input and optimized supporting strategies. The results indicate that the supporting effort can generally be reduced, e.g. overhang geometries with an angle to the horizontal of less than 35° can be manufactured without any support. The successful realization of the segmentation strategy in combination with optimized support structures allows the implementation of a stacking strategy, thereby using the available work space more efficiently.

null

['Poudel, Arun', 'Yasin, Mohammad Salman', 'Shao, Shuai', 'Shamsaei, Nima']

2023-02-10T14:23:05Z

2022

Mechanical Engineering

null

['https://hdl.handle.net/2152/117453', 'http://dx.doi.org/10.26153/tsw/44334']

eng

2022 International Solid Freeform Fabrication Symposium

Open

['Laser powder bed fusion (L-PBF)', 'Non-destructive testing', 'X-ray computed tomography', 'Process window', 'Rockwell hardness']

Assessing the Feasibility of Process Window Estimation for L-PBF Ti-6Al-4V through Hardness Measurements

Conference paper

https://repositories.lib.utexas.edu//bitstreams/7764f1b3-b6c3-4f12-a73d-85e1049cde9a/download

null

Optimizing the process window for an additively manufactured material using X-ray computed tomography (XCT) is a time-, labor-, and capital-intensive process where a large number of coupons need to be analyzed in the process parameter space. Hence, as a cheaper and faster alternative, this study assessed the relationship between relative density and hardness of laser powder bed fused (L-PBF) Ti-6Al-4V. Coupons with different levels of porosity were fabricated by changing the recommended laser power in the range of ±20% in an interval of 10%. The martensitic microstructure didn’t vary significantly with the change in laser power. On the other hand, Rockwell C hardness (HRC) did. HRC was observed to be in good correlation with the defect content in the coupons. Higher defect content in the coupons resulted in lower HRC and vice versa. Hence, the hardness measurement technique can be used to estimate the process window of L-PBF Ti-6Al-4V.

null

['Kletetzka, I.', 'Neitzel, F.', 'Schmid, H.-J.']

2024-03-25T22:31:21Z

2023

Mechanical Engineering

null

['https://hdl.handle.net/2152/124323', 'https://doi.org/10.26153/tsw/50931']

en_US

2023 International Solid Freeform Fabrication Symposium

Open

['laser sintering', 'powder', 'ceramic', 'additive manufacturing']

Assessing the Impact of the Powder Production Method on Ceramic-filled Polyamide Composites made by Laser Sintering

Conference paper

https://repositories.lib.utexas.edu//bitstreams/4b2f310c-35c4-4afe-bcb7-8fa7f5e63515/download

University of Texas at Austin

Polymer composites represent the industry standard in injection molding for the production of plastic components with increased requirements in terms of heat resistance and stiffness. In the field of laser sintering (LS), these materials are less common so far. In order to extend the available material variety for the LS process, new ceramic-filled Polyamide 613 powders are investigated within the scope of this work. Here, the resulting properties from two different powder production methods are compared. One filled powder is produced by dry blending and the other powder with the same filler and filling ratio is produced by encapsulating the filler particles inside the polymer particles within the dissolution-precipitation process. It was found that encapsulating the filler particles can provide certain benefits for the processability, for example an improved powder flowability or better filler dispersion. However, encapsulating the filler also alters the thermal properties of the precipitated powder.

null

['Hauser, C.', 'Childs, T.H.C.', 'Dalgarno, K.W.', 'Eane, R.B.']

2019-03-12T17:54:01Z

1999

Mechanical Engineering

null

['https://hdl.handle.net/2152/73605', 'http://dx.doi.org/10.26153/tsw/747']

eng

1999 International Solid Freeform Fabrication Symposium

Open

['Metallography', 'Atmosphere']

Atmospheric Control during Direct Selective Laser Sintering of Stainless Steel 314S Powder

Conference paper

https://repositories.lib.utexas.edu//bitstreams/dabd68c4-c148-4594-8e64-fb48c74d4917/download

null

Stainless steel grade 314S powders have been Selective Laser Sintered (SLS) in three different argon/air (oxygen) atmospheric mixtures. The amount of oxygen present during the heating, melting and fusing of the metal powder strongly limits the range of laser powers and scanning speeds for successful processing. As oxygen levels diminish, powder oxidation reduces. This reduces absorption of laser energy as well as balling and other detrimental surface phenomena. This paper reports the conditions for creating sintered layers and observations of part quality variation within these conditions. Sintered microstructure observations are also helpful in determining thermal history changes.

null

Koch

2018-05-03T18:25:19Z

1993

Mechanical Engineering

doi:10.15781/T2ZC7SB82

http://hdl.handle.net/2152/65053

eng

1993 International Solid Freeform Fabrication Symposium

Open

['DIGIBOT 3D', 'laser digitizer', '3D systems', 'CAD', 'CAM', 'CAE']

Automated 4 Axis Adaptive Scanning with the Digibotics Laser Digitizer

Conference paper

https://repositories.lib.utexas.edu//bitstreams/ecadda3e-47bd-4e2a-b7f4-7160840e6fb6/download

null

The DIGIBOT 3D Laser Digitizer is a high performance 3D input device which combines laser ranging technology, personal computing, and Microsoft Windows in an attractive desktop package. With its full four-axis scanning capabilities, the DIGIBOT provides a simple, accurate, and quick way to copy or inspect complex, sculpted surfaces. The DIGIBOT provides an effective solution for many industrial and academic problems involving 3D design, inspection, replication, analysis, and visualization/animation. By measuring sequential points and producing a standard list of x/y/z coordinates, the DIGIBOT interfaces to any CAD/CAM/CAE imaging or animation software that reads 3D points, contours, or triangular facets.

null

['Zhao, Xiyue', 'Imandoust, Aidin', 'Khanzadeh, Mojtaba', 'Imani, Farhad', 'Bian, Linkan']

2021-12-01T22:39:34Z

2021

Mechanical Engineering

null

['https://hdl.handle.net/2152/90642', 'http://dx.doi.org/10.26153/tsw/17561']

eng

2021 International Solid Freeform Fabrication Symposium

Open

['anomaly detection', 'melt pool monitoring', 'sparse representation', 'unsupervised learning', 'direct energy deposition', 'additive manufacturing']

Automated Anomaly Detection of Laser-Based Additive Manufacturing Using Melt Pool Sparse Representation and Unsupervised Learning

Conference paper

https://repositories.lib.utexas.edu//bitstreams/fa2422df-92ff-4ec2-83e7-65a0e2b11b56/download

University of Texas at Austin

Advanced thermal imaging is increasingly invested in direct energy deposition (DED) additive manufacturing (AM) to cope with information visibility of melt pool and tackle process inconsistency. However, there are key challenges regarding the feasibility of current image-guided monitoring methodologies in the DED process. First, high-resolution thermal images consist of millions of pixels captured by hundreds of frames lead to the curse of dimensionality in analysis. Second, the presence of various exogenous noise, ill-structured data, and significant cluster imbalance limit the capability of the current methodologies to perform real-time monitoring. The objective of this research is to advance the frontier of melt pool monitoring in DED process by designing an automated and unsupervised anomaly detection on high-dimensional thermal image data. Specifically, we develop a variational autoencoder to generate a low-dimensional representation of each input thermal image data. A Gaussian mixture model and K-Mean clustering are integrated with the generative model to split latent space into homogenous regions and detect anomalies. Experimental results show that the proposed methodology is highly effective in detecting defective melt pools with accuracy up to 94.52% and a false alarm rate of less than 2.1%.

null

['Khoshnevis, B.', 'Kwon, H.', 'Bukkapatnam, S.']

2019-10-18T16:37:59Z

2001

Mechanical Engineering

null

['https://hdl.handle.net/2152/76255', 'http://dx.doi.org/10.26153/tsw/3344']

eng

2001 International Solid Freeform Fabrication Symposium

Open

Contour

Automated Construction using Contour Crafting

Conference paper

https://repositories.lib.utexas.edu//bitstreams/e21a2cda-7539-4e0c-884d-f0c2a14ea52e/download

null

This paper presents some concepts and initial investigation of a novel construction automation approach using the Contour Crafting (CC) layered fabrication process, developed at the University of Southern California. CC uses computer control to take advantage of the superior surface forming capability of trowels, used by craftsmen and builders since ancient times, to create large intricate structures with smooth and accurate surfaces. The potential of CC became evident from the initial investigations and experiments with various materials and geometries. Using this process, a single house or a colony of houses, each with possibly a different design, may be automatically constructed in a single setup.

null

['Ramin, E.', 'Harris, R. A.']

2020-03-10T14:49:22Z

2007

Mechanical Engineering

null

['https://hdl.handle.net/2152/80211', 'http://dx.doi.org/10.26153/tsw/7230']

eng

2007 International Solid Freeform Fabrication Symposium

Open

Tissue Engineering scaffolds

Automated Design of Tissue Engineering Scaffolds by Advanced CAD

Conference paper

https://repositories.lib.utexas.edu//bitstreams/5fdae97c-8581-4cf8-a8b4-adb524e91907/download

null

The design of scaffolds with an intricate and controlled internal structure represents a challenge for Tissue Engineering. Several scaffold manufacturing techniques allow the creation of complex and random architectures, but have little or no control over geometrical parameters such as pore size, shape and interconnectivity- things that are essential for tissue regeneration. The combined use of CAD software and layer manufacturing techniques allow a high degree of control over those parameters, resulting in reproducible geometrical architectures. However, the design of the complex and intricate network of channels that are required in conventional CAD, is extremely time consuming: manually setting thousands of different geometrical parameters may require several days in which to design the individual scaffold structures. This research proposes an automated design methodology in order to overcome those limitations. The combined use of Object Oriented Programming and advanced CAD software, allows the rapid generation of thousands of different geometrical elements. Each has a different set of parameters that can be changed by the software, either randomly or according to a given mathematical formula, so that they match the different distribution of geometrical elements such as pore size and pore interconnectivity. This work describes a methodology that has been used to design five cubic scaffolds with pore size ranging from about 200 to 800 µm, each with an increased complexity of the internal geometry.

null

['Cooper, A.G.', 'Kang, S.', 'Kietzman, J.W.', 'Prinz, F.B.', 'Lombardi, J.L.', 'Weiss, L.']

2019-03-01T17:39:48Z

1998

Mechanical Engineering

null

['https://hdl.handle.net/2152/73519', 'http://dx.doi.org/10.26153/tsw/669']

eng

1998 International Solid Freeform Fabrication Symposium

Open

['Mold Shape Deposition', 'Ceramic materials']

Automated Fabrication of Complex Molded Parts Using Mold SOM

Conference paper

https://repositories.lib.utexas.edu//bitstreams/b6223daa-1c38-47d3-a09f-ef0fc87d8ff9/download

null

Mold Shape Deposition Manufacturing (Mold SDM) is a Solid Freeform Fabrication technique for producing complex shaped fugitive wax molds. A vari~ty of castable. polymer and ceramic materials have been used to make parts from these molds. ThIS paper descnbes the Mold SDM method and an automated mold building machine based on a commercial CNC mill. Process steps, material selection and equipment issues are explained. Alumina, silicon nitride, polyurethane and epoxy parts with feature sizes ranging from 0.5 to 30 mm will be shown, as well as preassembled mechanisms and multi-material parts.

null

['Klosterman, Don', 'Chartoff, Richard', 'Osborne, Nora', 'Graves, George']

2018-12-06T21:30:53Z

1997

Mechanical Engineering

doi:10.15781/T2SX64W60

http://hdl.handle.net/2152/71432

eng

1997 International Solid Freeform Fabrication Symposium

Open

['LOM', 'CMC']

Automated Fabrication of Monolithic and Ceramic Matrix Composites via Laminated Object Manufacturing (LaM)

Conference paper

https://repositories.lib.utexas.edu//bitstreams/2d02a74e-fe28-45b7-a8a2-ff86af5265ed/download

null

This report summarizes recent developments in a research program for fabricating advanced monolithic and ceramic matrix composite parts using Laminated Object Manufacturing (LOM). Both silicon carbide (SiC) and SiC/SiC composites are discussed. The LOM process is used to produce green forms that are then densified using various post processing operations. The monolithic ceramic LOM process was advanced through the implementation of an automated solvent spray bonding step, significant improvement in decubing with new software, and an intensive round ofmechanical characterization. The LOM process for making CMC green forms is fully developed. This entailed implementing a process for making suitable SiC fiber preforms, a laser cutting capability, a decubing strategy, and a binder resin cure procedure. Further research is ongoing for the post processing pyrolysis and reaction bonding steps as discussed herein.

null

['Steidle, Cheri', 'Klosterman, Don', 'Osborne, Nora', 'Graves, George', 'Chartoff, Richard']

2019-02-27T17:45:00Z

1998

Mechanical Engineering

null

['https://hdl.handle.net/2152/73508', 'http://dx.doi.org/10.26153/tsw/658']

eng

1998 International Solid Freeform Fabrication Symposium

Open

['Chemical Engineering', 'LOM']

Automated Fabrication of Nonresorbable Bone Implants Using Laminated Object Manufacturing (LOM)

Conference paper

https://repositories.lib.utexas.edu//bitstreams/a85b69a2-e075-429e-bf3e-1865b83501cc/download

null

['Mathewson, Brian B.', 'Newman, Wyatt S.', 'Heuer, Arthur H.', 'Cawley, James D.']

2018-11-02T14:59:11Z

1995

Mechanical Engineering

doi:10.15781/T2959CT1S

http://hdl.handle.net/2152/69332

eng

1995 International Solid Freeform Fabrication Symposium

Open

['CAD', 'custom manufacturing', '3D Laminated Engineering Components']

Automated Fabrication ofCeramic Components from Tape-Cast Ceramic

Conference paper

https://repositories.lib.utexas.edu//bitstreams/5be81cf5-85df-485e-bdb4-27b78ddc6aa9/download

null

This paper describes a machine and process for automated fabrication of functional 3-D laminated engineering components, ceramics in the present example. A laser cuts successive layers of a part derived from a CAD model description out of unfired tape-cast ceramic sheets vacuum-clamped to an x-y sled. A material-handling robot uses a selective-area gripper to extract only the desired part outlines from the surrounding waste material, then stacks the slices to build the part. This system design enables rapid manufacture of functional engineering components with arbitrarily complex internal and external geometries from virtually any material available in sheet form.

null

['Dakshnamoorthy, Vignesh', 'Taylor, Robert V.']

2021-11-01T21:19:33Z

2016

Mechanical Engineering

null

https://hdl.handle.net/2152/89757

eng

2016 International Solid Freeform Fabrication Symposium

Open

['lattice structure', 'optimization', 'hinge fitting', 'goose neck door hinge', 'part design', 'stiffness', 'additive manufacturing']

Automated Lattice Optimization of Hinge Fitting with Displacement Constraint

Conference paper

https://repositories.lib.utexas.edu//bitstreams/47d45fcc-d6dc-466c-a26b-98de52fb3e0c/download

University of Texas at Austin

Additive manufacturing enables fabrication of complex lattice cell structures that are not manufacturable using conventional methods. In order to exploit this lattice capability in structural designs, the effect on structural performance must be considered. This paper uses a goose neck door hinge component to illustrate the effects of lattice structure optimization when stiffness criteria drive part design. The effect of intermediate lattice cell density parameters on resulting lattice configurations from automated lattice structure optimization are studied and it is found that the compliance of the model depends upon the range of intermediate density elements present. The paper then compares the effect of a displacement constraint on optimized weight from rib-stiffened and lattice-stiffened shell models. It is shown that optimized weight results from the lattice configuration depend on part stiffness requirements. The results show that lattice structures can be successfully implemented in weight-critical components where relaxation in the displacement constraint is acceptable.

null

['Chang, Y. C.', 'Pinilla, J. M.', 'Kao, J.H.', 'Dong, J.', 'Ramaswami, K.', 'Prinz, F.B.']

2019-03-11T16:45:53Z

1999

Mechanical Engineering

null

['https://hdl.handle.net/2152/73582', 'http://dx.doi.org/10.26153/tsw/724']

eng

1999 International Solid Freeform Fabrication Symposium

Open

['SFF', 'CAD']

Automated Layer Decomposition for Additive/Subtractive Solid Freeform Fabrication

Conference paper

https://repositories.lib.utexas.edu//bitstreams/35b09cd4-ffc4-4e0c-94b4-0c6cbc82d722/download

null

The new additive/subtractiye technology (Shape. Deposition Manufacturing) enhances Solid Freeform Fabrication (SFF) capability inproducing near net-shape surface finish. This. technology also builds parts in fewer layers compared with conventional layered manufacturing technology. However, to decompose a part into freeform layers usually requires expensive geometric computation.. Also, to plan build. sequences often requires human intervention because ofthe complicated spatial relationships among the freeform layers. At present decomposition and build sequence planning are both performed by experienced designers/users. In this paper, a novel decomposition approach based on surface splitting is proposed to facilitate .computation and planning of the additive/subtractive SFF processes. The results shown in this paper are from models with 3D planar geometry. Continuous effort is devoted into extending and implementing this new approach for models with 3Dfreeform.geometry

null

['Wadidie, A.', 'Studer, G. M.', 'Villez, K.']

2024-03-27T03:18:46Z

2023

Mechanical Engineering

null

['https://hdl.handle.net/2152/124461', 'https://doi.org/10.26153/tsw/51069']

en_US

2023 International Solid Freeform Fabrication Symposium

Open

['large area additive manufacturing', '3D printing', 'thresholding', 'edge detection']

Automated layer identification in large area additive manufacturing (LAAM): A comparison of image thresholding and edge detection techniques

Conference paper

https://repositories.lib.utexas.edu//bitstreams/5981225d-ea2c-444f-9d76-bcc44c622817/download

University of Texas at Austin

Our study aims to develop an automated method for identifying layers on images of 3Dprinted walls from a LAAM printer, as manual identification is subjective and can be timeconsuming. We applied three different image processing methods to identify edges between layers: simple thresholding, Otsu thresholding, and Canny edge detection. Otsu thresholding was found to be the most accurate and required minimal manual intervention. From our study, we propose a new approach by going through essential steps for greater accuracy. This research demonstrates the feasibility of using computer-based methods to automatically identify layers in 3D printing, reducing manual time and effort and improving the strength and quality of 3D-printed parts.

null

['Rasoolian, Behnam', 'Pegues, Jonathan', 'Shamsaei, Nima', 'Silva, Daniel']

2021-11-30T20:22:53Z

2019

Mechanical Engineering

null

['https://hdl.handle.net/2152/90535', 'http://dx.doi.org/10.26153/tsw/17454']

eng

2019 International Solid Freeform Fabrication Symposium

Open

['additive manufacturing', 'fatigue behavior', 'roughness', 'radius of curvature']

An Automated Method for Geometrical Surface Characterization for Fatigue Analysis of Additive Manufactured Parts

Conference paper

https://repositories.lib.utexas.edu//bitstreams/c63b0cb0-a249-48fa-bcb7-ed65d7280e50/download

University of Texas at Austin

Recent interest to implement additive manufactured parts into structural applications has created a critical need to better understand the fatigue behavior of these parts. Alloys such as Ti-6Al-4V are popular in the aerospace and biomedical industries due to their superior strength to weight ratio and biocompatibility. Previous works have associated fatigue behavior with surface roughness, especially radius of curvature of notches. It is therefore important to develop a fast, reliable and consistent methodology for extracting such curvatures. The contribution of this paper is in providing an automated method for extracting radius of curvature using image processing techniques and optimization. Results on fatigue life prediction indicates similar results between the automated method and manually extracted radii in a significantly shorter period of time.

null

['Borish, Michael', 'Roschli, Alex']

2023-01-26T14:51:21Z

2022

Mechanical Engineering

null

['https://hdl.handle.net/2152/117311', 'http://dx.doi.org/10.26153/tsw/44192']

eng

2022 International Solid Freeform Fabrication Symposium

Open

['slicing', 'Additive manufacturing', 'wire coextrusion', 'wire embedding', 'self-heating molds', 'composite']

Automated Path Planning for Wire Feeding in Large Format Polymer Additive Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/eabf70cf-d5ed-40a4-9720-215ee4a304ba/download

null

Polymer-based large format industrial additive manufacturing (AM) technology continues to expand into new application areas. One area of interest is large scale composite molds and dies. These molds and dies can be used for out-of-autoclave tooling applications. However, at these sizes, several challenges remain that prevent the use of AM technology due to cost. One such challenge is the need to heat these molds in large thermal ovens. To address this challenge, researchers at Oak Ridge National Laboratory developed the necessary hardware to allow co-extruded wire to be embedded into the material during construction. Using this hardware, a demonstration mold was successfully constructed and subjected to mechanical testing. The construction of this object required a unique pathing solution to achieve success. In this paper, we describe the needed software development in ORNL Slicer 2.0 to allow the automated production of this unique pathing solution.

null

['Dong, Jianpeng', 'Kao, Ju-Hsien', 'Pinilla, Jose M.', 'Chang, Yu-Chi', 'Prinz, Fritz B.']

2019-03-11T16:47:56Z

1999

Mechanical Engineering

null

['https://hdl.handle.net/2152/73583', 'http://dx.doi.org/10.26153/tsw/725']

eng

1999 International Solid Freeform Fabrication Symposium

Open

['CAD', 'CAM']

Automated Planning for Material Shaping Operations in Additive/Subtractive Solid Freeform Fabrication

Conference paper

https://repositories.lib.utexas.edu//bitstreams/f19fb637-eb29-4c87-8867-017897ac6dd2/download

null

Combining the advantages of layered manufacturing and material removal processes, additive/subtractive solid freeform fabrication (A/S SFF) can build parts with complex shapes without compromising precision requirements. However, preparing material removal operations requires special expertise, which has in fact become one of the bottlenecks of the A/S SFF manufacturing process. To achieve automated planning, a shaping process planner is being developed based on. 3D solid representation and a surface classification scheme. This planner can generate numeric control (NC) codes for CNC milling in an automatic fashion on non-undercut features of arbitrary 3D input geometry. Planning approaches are also presentedinorde~to>shape parts accurately and efficiently. The proposed shaping planner thus delivers on the promise offully automated process planning in A/S SFF.

null

['Bohn, John Helge', 'Wozny, Michael J.']

2018-04-19T16:20:26Z

1992

Mechanical Engineering

doi:10.15781/T2QJ78F8R

http://hdl.handle.net/2152/64380

eng

1992 International Solid Freeform Fabrication Symposium

Open

['CAD-models', 'de facto', 'CAD-models']

Automatic CAD-model Repair: Shell-Closure

Conference paper

https://repositories.lib.utexas.edu//bitstreams/8f26990e-8520-43f0-a295-e23658000bfe/download

null

Shell-closure is critical to the repair of CAD-models described in the .STL file-format, the de facto solid freeform fabrication industry-standard. Polyhedral CAD-models that do not exhibit shell-closure, i.e. have cracks, holes, or gaps, do not constitute valid solids and frequently cause problems during fabrication. This paper describes a solution for achieving shell-closure of polyhedral CAD-models. The solution accommodates nonmanifold conditions, and guarantees orientable shells. There are several topologically ambiguous situations that might arise during the shell-closure process, and the solution applies intuitively pleasing heuristics in these cases.

null

['Mireles, Jorge', 'Terrazas, Cesar', 'Medina, Francisco', 'Wicker, Ryan']

2021-10-11T22:09:27Z

8/16/13

Mechanical Engineering

null

['https://hdl.handle.net/2152/88663', 'http://dx.doi.org/10.26153/tsw/15597']

eng

2013 International Solid Freeform Fabrication Symposium

Open

['Arcam A2 Electron Beam Melting', 'Electron Beam Melting', 'automatic feedback control', 'temperature stabilization', 'infrared camera']

Automatic Feedback Control in Electron Beam Melting Using Infrared Thermography

Conference paper

https://repositories.lib.utexas.edu//bitstreams/9ccafcc0-24f5-4390-ad23-ceb4d77f518c/download

University of Texas at Austin

An infrared (IR) camera has been installed in an Arcam A2 Electron Beam Melting (EBM) system for improved layer-by-layer monitoring and feedback control of the EBM build process. Previous work has demonstrated the temperature variations possible during a build (e.g., part/powder bed temperature elevates as build height increases) that have been shown to produce microstructural changes as well as a range of defects that can be detected (e.g., temperature anomalies and porosity). A stabilization of temperature during a build can lead to more uniform microstructure and mechanical properties throughout the fabricated part. Further, full spatial and temporal control of temperature could lead to controlled microstructural architectures in EBM-fabricated parts. An automatic feedback control system was developed to acquire a temperature matrix of the current layer and used as an input to a ‘ghost operator’ that modifies the necessary parameters (speed function, beam current, melt cycle’s post-heating time) for temperature stabilization to minimize microstructural variations.

null

['Cook, D.', 'Knier, B.', 'Gervasi, V.', 'Stahl, D.']

2021-09-30T19:56:45Z

2010

Mechanical Engineering

null

['https://hdl.handle.net/2152/88289', 'http://dx.doi.org/10.26153/tsw/15230']

eng

2010 International Solid Freeform Fabrication Symposium

Open

['solid-freeform-fabrication', 'finite-element analysis', 'minimal-mass lattice structures', 'structural performance', 'process parameters', 'multi-functional structures', 'high-performance-computing']

Automatic Generation of Strong, Light, Multi-Functional Structures from FEA Output

Conference paper

https://repositories.lib.utexas.edu//bitstreams/4563c28d-e4c0-44d1-8b63-2295b6c46382/download

University of Texas at Austin

An automated process is being developed that will generate a minimal-mass lattice structure that is fabrication-ready for a selected solid-freeform-fabrication (SFF) process. The results of a standard, structural, finite-element analysis (FEA) are processed to define the selection, alignment and sizing of unit lattice elements, such that a minimal-mass structure can be defined. This process will allow for considerations of structural performance (e.g. safety factor), multiple loads, as well as process parameters (e.g. materials and min./max. sizes). Further development would lead to the definitions of composites and multi-functionality, as well as high-performance-computing (HPC) capabilities.

null

['Ridwan, S.', 'Mireles, J.', 'Gaytan, S.M.', 'Espalin, D.', 'Wicker, R.B.']

2021-10-12T22:31:50Z

2014

Mechanical Engineering

null

['https://hdl.handle.net/2152/88756', 'http://dx.doi.org/10.26153/tsw/15690']

eng

2014 International Solid Freeform Fabrication Symposium

Open

['layerwise monitoring', 'spatial monitoring', 'infrared camera', 'electron beam melting', 'infrared thermography', 'thermal data', 'geometric data']

Automatic Layerwise Acquisition of Thermal and Geometric Data of the Electron Beam Melting Process using Infrared Thermography

Conference paper

https://repositories.lib.utexas.edu//bitstreams/133f5c95-d166-4694-8727-fd1232af5af1/download

University of Texas at Austin

Layerwise monitoring has become an area of interest in the field of additive manufacturing because of potential to further enable part qualification during every stage of fabrication. Spatial monitoring and qualification during part fabrication has never before been possible with traditional manufacturing processes such as milling or casting. An IR camera has been externally annexed atop an EBM system to obtain layerwise thermographs throughout the fabrication process. This paper demonstrates a process to compare each layer of fabrication using automatically acquired thermal images to the corresponding CAD file for each fabricated object. Two different methods of image analysis for part detection were compared (analysis on the basis of color and analysis by edge detection). Detection allowed the quantification of processing information (average temperature and surface anomalies) and geometric information (surface area and perimeter). A percent error of the compared surface area was found to range from 5%- 17%, and automatically acquired temperature measurements were within 7.8K of the recorded thermograph. The methods presented in this research showcase the beginning steps of integrated metrology in advanced manufacturing systems and automatic monitoring of per-part thermal behavior and part quality.

null

['Thomas, Charles L.', 'Hayworth, Kenneth J.']

2018-11-14T17:23:11Z

1996

Mechanical Engineering

doi:10.15781/T2C82508X

http://hdl.handle.net/2152/70245

eng

1996 International Solid Freeform Fabrication Symposium

Open

['3D object', 'thermoplastic droplet deposition process', '3D aliasing']

Automating Sheet-Based Fabrication: The Conveyed-Adherent Process

Conference paper

https://repositories.lib.utexas.edu//bitstreams/94788f8e-f1ae-4892-9e06-add8ab41e84e/download

null

A new automated fabrication technology is described which breaks the fabrication process into spatially separate layer-formation and layer-bonding stages. The technique uses sheet material on a substrate as feedstock and cuts cross-section contours into the material before conveying the material on the substrate to a stacking station. Advantages include (a) speed, (b) versatility in fabrication materials, and (c) ability to fabricate hollows, embed or cast secondary materials, and selectively enhance or degrade material properties on a regional basis. A prototype fabricator has been built which automates all aspects ofthis process except weeding. Applications demonstrated using this machine include traditional rapid prototyping and visualization-model creation as well as functional machines taking advantage of embedding and cast-in-place techniques.

null

['Stroble, J. K.', 'Landers, R. G.', 'Liou, F. W.']

2020-03-05T18:55:53Z

9/14/06

Mechanical Engineering

null

['https://hdl.handle.net/2152/80143', 'http://dx.doi.org/10.26153/tsw/7164']

eng

2006 International Solid Freeform Fabrication Symposium

Open

Laser Aided Manufacturing Process

Automation of a Hybrid Manufacturing System Through Tight Integration of Software and Sensor Feedback

Conference paper

https://repositories.lib.utexas.edu//bitstreams/ab004900-e7bf-4a6b-81f7-cab9563988d9/download

null

This paper presents a framework for the automation of the Laser Aided Manufacturing Process (LAMP) lab at the University of Missouri-Rolla. The groundwork for the proposed system involves the integration of the LabVIEW software package and a PXI-8195 real time controller with several sensors and actuators. The incorporation of all key control parameters into one virtual instrument will help achieve the goal of an automated hybrid system. To achieve this goal, a five-phase plan, which will be further discussed in the paper, has been developed. The first phase of this plan, which includes the deposition of a thin walled structure without DNC communication between LabVIEW and the CNC has been achieved, and will be the focus of this paper

null

['Ye, Jiafeng', 'Yasin, Mohammad Salman', 'Muhammad, Muztahid', 'Liu, Jia', 'Vinel, Aleksandr', 'Slvia, Daniel', 'Shamsaei, Nima', 'Shao, Shuai']

2021-12-01T22:18:09Z

2021

Mechanical Engineering

null

['https://hdl.handle.net/2152/90636', 'http://dx.doi.org/10.26153/tsw/17555']

eng

2021 International Solid Freeform Fabrication Symposium

Open

['nitinol', 'laser beam-powder bed fusion', 'process parameters', 'Bayesian optimization']

Bayesian Process Optimization for Additively Manufactured Nitinol

Conference paper

https://repositories.lib.utexas.edu//bitstreams/dba1a8f6-d315-4aa0-88c3-40882cba161e/download

University of Texas at Austin

Additively manufactured nitinol enables the design and rapid prototyping of the shape memory alloy with great flexibility and cost-effectiveness in various applications. To achieve high-density fabrication of nitinol, we utilize a Gaussian process-based Bayesian optimization method to efficiently optimize process parameters of the laser beam-powder bed fusion (LB-PBF) process in this work. Specifically, Gaussian process regression is applied to formulate a surrogate model between the critical process parameters (i.e., laser power, scanning speed) and the residual porosity of the nitinol samples. Then Bayesian optimization is integrated to successively explore the design space to search for the optimal process parameters. These two methods are integrated to find the global optimum iteratively. Compared with the traditional trial-and-error methods, the proposed method can quickly find the optimal process parameter for the high-quality nitinol samples, especially with many process parameters, and accelerate the innovations with nitinol in additive manufacturing.

null

['Maskery, I.', 'Aremu, A.O.', 'Simonelli, M.', 'Tuck, C.', 'Wildman, R.D.', 'Ashcroft, I.A.', 'Hague, R.J.M.']

2021-10-13T20:45:58Z

2014

Mechanical Engineering

null

['https://hdl.handle.net/2152/88782', 'http://dx.doi.org/10.26153/tsw/15716']

eng

2014 International Solid Freeform Fabrication Symposium

Open

['selective laser melting', 'lattice', 'aluminum alloy']

The BCC Unit Cell for Latticed SLM Parts; Mechanical Properties as a Function of Cell Size

Conference paper

https://repositories.lib.utexas.edu//bitstreams/750511b9-39f2-48b7-b80c-5f45fe862d18/download

University of Texas at Austin

The existing framework describing the mechanical properties of lattices places strong emphasis on one important property, the relative density of the repeating cells. In this work, we explore the effects of cell size, attempting to construct more complete models for the performance of lattices. This was achieved by examining the elastic modulus and ultimate tensile strength of latticed parts with a range of unit cell sizes and fixed density. The parts were produced by selective laser melting (SLM). The examined cell type was body-centred-cubic (BCC), a cell of high relevance for SLM because of its self-supporting structure. We obtained power law relationships for the mechanical properties of our latticed specimens as a function of cell size, which are similar in form to the existing laws for the density dependence. These can be used to predict the properties of latticed column structures comprised of BCC cells, and may be easily amended for other situations. In addition, we propose a novel way to analyse the elastic modulus data, which may lead to more general models, applicable to parts of varying size. Lastly, our general methodology may be of use in future studies which explore the other parameters that determine lattice performance; the choice of cell type, the global shape of the lattice structure and the type of stress.

null

['Ramirez-Chavez, Irving E.', 'Lee, Christine', 'Bhate, Dhruv']

2023-02-24T14:45:29Z

2022

Mechanical Engineering

null

['https://hdl.handle.net/2152/117524', 'http://dx.doi.org/10.26153/tsw/44404']

eng

2022 International Solid Freeform Fabrication Symposium

Open

['Additive Manufacturing', 'beam deletion', 'cellular materials', 'densification strain', 'maximum transmitted stress', 'perturbation', 'energy absorption']

Beam Deletion in Square Honeycombs for Improved Energy Absorption Under Quasi-Static In-Plane Compression

Conference paper

https://repositories.lib.utexas.edu//bitstreams/c6d4caf4-d501-4750-839f-541dd5f30763/download

null

When selecting cellular materials for energy absorption applications, there have traditionally been two choices: a periodic structure such as a honeycomb, or a stochastic one, as seen in foams. Both choices involve a global definition governing the allocation of the members of the structure, be they beams or surfaces. With Additive Manufacturing, the exploration of more complex structures enables the creation of aperiodicity through the local modification of periodic structures. This paper explores one application of this approach by deleting beams in square honeycombs, with the aim of avoiding localization of failure that generates significant undulations in the stress plateau under in-plane quasi-static compression. These perturbed structures show improved energy absorption behavior by generating higher Specific Energy Absorption for a given transmitted stress and relative density than their periodic counterparts. This work thus argues for further exploration of localized aperiodicity as an approach to finely tune energy absorption performance.

null

['Li, Yongqiang', 'Chen, Yong']

2021-09-30T20:00:56Z

9/23/10

Mechanical Engineering

null

['https://hdl.handle.net/2152/88290', 'http://dx.doi.org/10.26153/tsw/15231']

eng

2010 International Solid Freeform Fabrication Symposium

Open

['topology optimization', 'principal stress line', 'beam structures', 'minimum compliance']

Beam Structure Optimization for Additive Manufacturing based on Principal Stress Lines

Conference paper

https://repositories.lib.utexas.edu//bitstreams/8d06615f-9061-4db0-add4-682c5ae4adbb/download

University of Texas at Austin

The benefits of component design with cellular structures have been demonstrated in a wide variety of applications. The recent advances in additive manufacturing and high performance computing have enabled us to design a product component with adaptive cellular structures to achieve significantly better performance. However, designing a product component with such structures, especially its shape and topology, poses significant challenges. Many approaches in topology optimization have been developed before for the purpose. In this paper, we present a novel structural optimization method based on the principal stress line analysis of a continuum domain. We first present the theoretical basis of our optimization method. We then discuss the properties of principal stress lines and their computation in a given design domain. Accordingly a novel structural optimization method is presented including size, shape and topology optimization. Related mathematical formulations and algorithms are also given for generating a beam structure with the minimum compliance. Three test cases are presented to illustrate the presented method.

null

['Johnson, W.M.', 'Rowell, M.', 'Deason, B.', 'Eubanks, M.']

2021-10-04T21:18:43Z

2011

Mechanical Engineering

null

['https://hdl.handle.net/2152/88349', 'http://dx.doi.org/10.26153/tsw/15288']

eng

2011 International Solid Freeform Fabrication Symposium

Open

['Additive Manufacaturing', 'benchmarking models', 'open source AM system', 'fused deposition modeling']

Benchmarking Evaluation of an Open Source Fused Deposition Modeling Additive Manufacturing System

Conference paper

https://repositories.lib.utexas.edu//bitstreams/860a3433-80c5-49c1-9fe4-77299d93babf/download

University of Texas at Austin

The availability of more affordable open source Additive Manufacturing (AM) systems has lead to the increased awareness and use of AM technologies. However, further expansion will necessitate improved reliability and an increased understanding in the limitations of these systems. This paper will review previous benchmarking models, and present the development of a new benchmarking model and its application in the evaluation of an open source AM system based on fused deposition modeling (FDM). The proposed benchmarking model includes various geometric features to evaluate the AM system in terms of dimensional accuracy, thermal warpage, staircase effect, and geometric and dimensional tolerances.

null

['Yasa, E.', 'Demir, F.', 'Akbulut, G.', 'Cızıoğlu, N.', 'Pilatin, S.']

2021-10-12T22:42:40Z

2014

Mechanical Engineering

null

['https://hdl.handle.net/2152/88760', 'http://dx.doi.org/10.26153/tsw/15694']

eng

2014 International Solid Freeform Fabrication Symposium

Open

['powder-bed metal fusion', 'additive manufacturing', 'Inconel 625', 'AM machine']

Benchmarking of Different Powder-Bed Metal Fusion Processes for Machine Selection in Additive Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/d85c45bf-72dc-4bb1-93c4-49556fca37c3/download

null

In the last decade, additive manufacturing has gained significant interest for direct part production and started to change the way companies manufacture products; even in very demanding sectors like aerospace. The biggest challenge for a wider industrial acceptance still stands as the need for more reliable, repeatable and precise machines for additive manufacturing. This paper presents a comprehensive benchmarking study for the selection of an additive manufacturing machine for powder-bed metal fusion process, i.e. Selective Laser Melting or Direct Metal Laser Sintering or Laser Cusing. Four different machine vendors for the same technology to be employed for aeroengine part manufacturing using Inconel 625 powder have been involved for comparing different machine specifications. Many aspects such as dimensional accuracy, surface quality, need of support structures, density, hardness and process limits (minimum wall thickness, overhang surfaces, inclinations and curvatures, etc.) are addressed in the paper. The state-of-the-art in machines for powder-bed metal fusion process is presented aiming at understanding the current limitations of the technology available today.

null

['Jayaram, Dureen', 'Bagchi, Amit', 'Jara-Almonte, C.C.', 'Oreilly, Sean']

2018-09-27T19:48:41Z

1994

Mechanical Engineering

doi:10.15781/T2BG2HV81

http://hdl.handle.net/2152/68608

eng

1994 International Solid Freeform Fabrication Symposium

Open

['Rapid prototyping', 'SLS', 'LOM']

Benchmarking of Rapid Prototyping Systems - Beginning to Set Standards

Conference paper

https://repositories.lib.utexas.edu//bitstreams/c427b662-4f55-4313-8d08-9289cf87eee6/download

null

Many rapid prototyping (RP) technologies are available today and more are being developed around the world. The absence of benchmarking standards in the RP industry has led manufacturers to use their own standards and make claims about superior performance. The need for testing standards is already felt; standardization will become imperative in the near future. The present work aims to lay the groundwork for the development of standards to measure various performance factors. Issues such as appearance and finish are studied qualitatively; the test part and some findings are presented. Issues such as repeatability, warpage, curl, creep, shrinkage and tensile strength are proposed to be studied quantitatively; test parts designed for studying these are described. Benchmarking standards will help users choose proper systems for their applications and help operators in monitoring machine performance, enabling better control over part building.

null

['Al Nabhani, Dawood', 'Kassab, Ali', 'Habbal, Osama', 'Mohanty, Pravansu', 'Ayoub, Georges', 'Pannier, Christopher']

2024-03-25T22:04:26Z

2023

Mechanical Engineering

null

['https://hdl.handle.net/2152/124311', 'https://doi.org/10.26153/tsw/50919']

en_US

2023 International Solid Freeform Fabrication Symposium

Open

['additive manufacturing', 'recycling', 'PLA', '2023 Solid Freeform Fabrication Symposium']

Benchmarking the Tensile Properties of Polylactic Acid (PLA) Recycled Through Fused Granule Fabrication Additive Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/fc18f980-2e7a-4365-a034-a4c28a2df445/download

University of Texas at Austin

To progress toward a circular economy of thermoplastic polymers, the adoption of 3D printers to make functional articles can facilitate distributed recycling. To this end, the mechanical degradation of polymers through multiple recycling cycles must be quantified. This work presents a procedure and benchmark dataset of tensile property degradation for polylactic acid (PLA) feedstock in multiple recycling passes with a fused granule fabrication process. To establish recycling with minimal processing (shredding and sieving), modifications were required to the granule feeding hopper of the 3D printer. Two distinct orientations were chosen to obtain tensile test coupons. These coupons were die-cut from machined 3D printed rectangular cross-section tubes, with one orientation along the bead (0°) and the other perpendicular to it (90°). Tensile properties are presented for 3D printed virgin material and one, two, three, and four passes of recycling. In terms of print orientation, the results indicate that samples pulled at 0° and 90° exhibited similar mechanical properties. However, there was an average decrease of 3.1% in ultimate tensile strength and a 1.7% decrease in elastic modulus for the samples along 90° orientation for all recycling passes. The samples along 0° demonstrated a 13.7% higher strain at fracture compared to those along 90°. Regarding the number of recycling passes, the findings suggest that the mechanical characteristics of PLA remain largely unaffected even after undergoing four recycling cycles. However, when the material is pulled in the direction of the bead, a 3.09% decrease in ultimate tensile strength is observed in the fourth recycling pass. The elastic modulus and strain at fracture did not exhibit a clear trend. It is important to note that the testing results display some variability, which can be attributed to a combination of stochasticity in the printing process and the preparation procedure employed.

null

Walczyk, Daniel F.

2019-02-19T19:36:41Z

1998

Mechanical Engineering

null

['https://hdl.handle.net/2152/73435', 'http://dx.doi.org/10.26153/tsw/587']

eng

1998 International Solid Freeform Fabrication Symposium

Open

['RP methods', 'steel laminations']

Bevel Cutting Methods and Cutting Trajectory Control for Steel Laminations Used in Tooling

Conference paper

https://repositories.lib.utexas.edu//bitstreams/270a95fa-92c0-4da3-95da-2293556ce1b2/download

null

Bevel cutting of steel laminations used in profiled-edge laminated tooling allows for a more accurate representation of the intended die surface, since stair-stepping at the edges is eliminated. Based on experiments involving maximum cutting speed, bevel angle and kerf quality, the three recommended methods for bevel cutting steel are (best to worst) pulsed Nd:YAG laser with hard-optic delivery, abrasive water jet, and machining with the flute edge of an endmill. For each method, bevel angles of up to 80 degrees are possible. Further experimentation was used to determine the optimal process parameters for kerf quality, with constant cutting speed being one ofthe main requirements. Finally, a new techIlique to assure constant velocity along the entire lamination cutting trajectory is developed.

null

['Nassar, A.R.', 'Reutzel, E.W.']

2021-10-19T19:10:06Z

2015

Mechanical Engineering

null

https://hdl.handle.net/2152/89326

eng

2014 International Solid Freeform Fabrication Symposium

Open

['directed energy deposition', 'layer-by-layer manufacturing', 'additive manufacturing', 'overhangs', 'Ti-6Al-4V']

Beyond Laser-by-Laser Additive Manufacturing - Voxel-Wise Directed Energy Deposition

Conference paper

https://repositories.lib.utexas.edu//bitstreams/15de08ed-f4e7-4206-a0ab-fb7722377a68/download

University of Texas at Austin

Conventional additive manufacturing is a layer-by-layer process, reliant on the sequential deposition of 2-1/2 D layers oriented along a build axis. During directed energy deposition a feedstock is directed into a continuous melt pool formed by a laser or electron beam. The ability to produce overhangs is limited due to the gravitational, surface tensions, and fluid-flow force acting on unsupported melt pools. Here, we present a novel, directed-energy-deposition technique where vertical and overhanging structures are formed by laser power modulation and the motion of a laser beam in three dimensional space along the build-up direction, rather than strictly in a single layer. We demonstrate that highly-overhanging Ti-6Al-4V structure, i.e. in which the overhang angle exceeds 45 degrees with respect to the x-y plane, can be deposited using the developed technique. High-speed imaging is used to gain insight into the physics of the process. The use of a pulsed or power-modulated beam is found to be critical to the formation of overhangs.

null

['Post, Brian K.', 'Richardson, Bradley', 'Lind, Randall', 'Love, Lonnie J.', 'Lloyd, Peter', 'Kune, Vlastimil', 'Rhyne, Breanna J.', 'Roschli, Alex', 'Hannan, Jim', 'Nolet, Steve', 'Veloso, Kevin', 'Kurup, Parthiv', 'Remo, Timothy', 'Jenne, Dale']

2021-11-08T21:14:09Z

2017

Mechanical Engineering

null

['https://hdl.handle.net/2152/90043', 'http://dx.doi.org/10.26153/tsw/16964']

eng

2017 International Solid Freeform Fabrication Symposium

Open

['big area additive manufacturing', 'wind turbine molds', 'wind turbine', 'tooling']

Big Area Additive Manufacturing Application in Wind Turbine Molds

Conference paper

https://repositories.lib.utexas.edu//bitstreams/4bd41921-cad5-4749-b193-587b24dccb3a/download

University of Texas at Austin

Tooling is a primary target for current additive manufacturing (AM), or 3D printing, technology because of its rapid prototyping capabilities. Molds of many sizes and shapes have been produced for a variety of industries. However, large tooling remained out of reach until the development of large-scale composite AM manufacturing processes like the Big Area Additive Manufacturing (BAAM) system. The Department of Energy’s Oak Ridge National Laboratory (ORNL) worked with TPI Composites to use the BAAM system to fabricate a wind turbine blade mold. The fabricated wind turbine blade mold was produced in 16 additively manufactured sections, was 13 meters long, had heating channels integrated into the design, and was mounted into a steel frame post fabrication. This research effort serves as a case study to examine the technological impacts of AM on wind turbine blade tooling and evaluate the efficacy of this approach in utility scale wind turbine manufacturing.

null

['Liggett, J.C.', 'Snelling, D.A.', 'Xu, M.', 'Myers, O.J.', 'Thompson, S.M.']

2021-12-06T21:37:22Z

2021

Mechanical Engineering

null

['https://hdl.handle.net/2152/90680', 'http://dx.doi.org/10.26153/tsw/17599']

eng

2021 International Solid Freeform Fabrication Symposium

Open

['high chromium white iron', 'bimetallic castings', 'wear performance', 'lattice structures', 'metal additive manufacturing', '316L']

Bimetallic Castings for Wear Performance through Infiltration of Additive Manufactured Metal Lattice Structures

Conference paper

https://repositories.lib.utexas.edu//bitstreams/6ee9c895-d990-4a67-9e51-1d969aa6aef6/download

University of Texas at Austin

High chromium white iron is an alloy frequently employed in the production of abrasion resistive wear components. Ground engaging components for mining or earthmoving frequently require such materials, as well as slurry pumps for mining applications. Although high chromium white iron alloy demonstrates excellent wear performance due to the formation of chromium carbides, it is brittle and lacks toughness. Impact resistance is often of great importance for ground engaging wear components; hence, this study will investigate a method by which high chromium white iron wear components may be reinforced by the formation of a bimetallic composite. In this research, an additively manufactured lattice structure of 316L stainless steel is infiltrated with high chromium white iron via the metal casting process. This procedure results in a bimetallic casting of reinforced white iron. Complete infiltration and metallurgical diffusion bonding were observed between the two alloys, validating this method as a means of reinforcing high chromium white iron castings for applications requiring high abrasion and impact resistance.

null

['Chakravarthy, Kumaran M.', 'Bourell, David L.']

2021-09-30T18:28:16Z

2010

Mechanical Engineering

null

['https://hdl.handle.net/2152/88271', 'http://dx.doi.org/10.26153/tsw/15212']

eng

2010 International Solid Freeform Fabrication Symposium

Open

['binder system', 'non metallics', 'bipolar plates', 'SLS', 'graphite-phenolic parts']

Binder Development for Indirect SLS of Non Metallics

Conference paper

https://repositories.lib.utexas.edu//bitstreams/4e7647de-d636-44fa-8263-3e7abd675c1e/download

University of Texas at Austin

In this work, a binder system for non metallics such as graphite has been developed and tested. A graphite-phenolic mixture was used for making bipolar plates using SLS. Phenolic resin melts (~90°C) instead of cross-linking (~165°C) in the SLS machine. During post processing in a furnace, the SLS parts slumped due to remelting of phenolic resin with no other binder present to hold the powder together. To prevent this slumping and to increase the green strength of the SLS parts, a new binder system was developed with Nylon/11 added. Nylon/11 has a melting point of ~185°C and is able to hold the SLS part together until the phenolic can cross link, preventing slumping. Single layer scan experiments with different compositions and SLS parameters were run to identify optimum composition and SLS parameters. Three point bend specimens were prepared with 70 wt. % Graphite-25 wt. % Phenolic- 5 wt. % Nylon/11 and 70 wt. % Graphite-20 wt. % Phenolic- 10 wt. % Nylon/11, tested and compared to graphite-phenolic parts. No significant increase in green strength was attained with Nylon/11 addition.

null

['Volpp, J.', 'Zhang, W.', 'Abbott, W.', 'Coban, A.', 'McConnell, S.', 'Marola, S.', 'Casati, R.', 'Padamati, R.', 'Lupoi, R.']

2024-03-25T23:26:43Z

2023

Mechanical Engineering

null

['https://hdl.handle.net/2152/124335', 'https://doi.org/10.26153/tsw/50943']

en_US

2023 International Solid Freeform Fabrication Symposium

Open

['powder sheet processing', 'laser materials processing', 'vaporization', 'spatter', 'additive manufacturing']

Binder evaporation during powder sheet Additive Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/64aab548-a645-4f43-b0c4-49de6ce95ab3/download

University of Texas at Austin

Several Additive Manufacturing methods are well established and found access into regular production in multiple sectors. For processing metals, typically wire or powder is used as feedstock. Wire processing is typically used for comparably large structure building, while powder processes offer, in general, a more precise metal application. For Powder Bed Fusion processes, very fine powder is used (typical 20 µm to 65 µm), while for Directed Energy Deposition powders are in the range between 50 µm and 160 µm. Such fine powders can be a health risk for humans (aspiration, skin integration). Avoiding contact with the powders in a production environment can be a big effort or not avoidable. Therefore, an alternative process was developed that provides the powder not as free powder particles but in form of powder sheets. For enabling the necessary bonding between the particles, a binder is used. In order to understand the impact of the binder during laser processing of the powder sheets, single pulse and line treatments were produced and recorded with high-speed imaging. Recordings show the vaporization of the binder and the related ejections of powder particles. At lower energy input, the binder evaporation led to less spattering, which indicates that a binder heating at low heating rates induces less pressure on the powder particles.

null

['Pekin, Senol', 'Zangvil, Avigdor', 'Ellingson, William']

2019-03-01T17:21:42Z

1998

Mechanical Engineering

null

['https://hdl.handle.net/2152/73512', 'http://dx.doi.org/10.26153/tsw/662']

eng

1998 International Solid Freeform Fabrication Symposium

Open

['FDC', 'EVA-wax']

Binder Formulation in EVA-wax system for Fused Deposition of Ceramics

Conference paper

https://repositories.lib.utexas.edu//bitstreams/732d6614-bf6b-46de-84ea-0359e2b6c5ac/download

null

Blends in the ethylene vinyl acetate (EVA) - wax system have been evaluated as potential binders.to be used in fused deposition of ceramics (FDC). In order to obtain good handling strength, it was indicated that the melting point of the polymer needs to be lower than that of the wax. In this context, it was shown that the melting point of the EVA decreases as the vinyl acetate content in the copolymer increases. By measuring the viscosity as a macroscopic property, it was shown that 20 % vinyl acetate-containing EVA is miscible in microcrystalline wax up to, atleast, 30 %.Binders used in FDC need to have low viscosity and it was pointed out that the slumping can be one main problem associated with binders with low viscosity. Thus, thermolysis of wax at low temperature is suggested as a solution. The volumetric thermal expansion and melt strength of an EVA-wax blend were displayed as a function of temperature, in the form of a penetration test.

null

['Agarwal, Kuldeep', 'Vangapally, Sairam', 'Sheldon, Alexander']

2021-11-04T21:05:01Z

2017

Mechanical Engineering

null

['https://hdl.handle.net/2152/90028', 'http://dx.doi.org/10.26153/16949']

eng

2017 International Solid Freeform Fabrication Symposium

Open

['binder jet additive manufacturing', 'binder jetting', 'biocomposite', 'tricalcium phosphate', 'stainless steel', 'bone scaffolds', 'implants']

Binder Jet Additive Manufacturing of Stainless Steel - Tricalcium Phosphate Biocomposite for Bone Scaffold and Implant Applications

Conference paper

https://repositories.lib.utexas.edu//bitstreams/c309633c-bad0-4473-aaad-d2304737a420/download

University of Texas at Austin

Scaffolds are 3D biocompatible structures that mimic the extracellular matrix properties (mechanical support, cellular activity and protein production) of bones and provide place for cell attachment and bone tissue formation. Their performance depends on chemistry, pore size, pore volume, and mechanical strength. Recently, additive manufacturing (AM) has been used as a means to produce these scaffolds. This paper explores a new biocomposite manufactured using Binder Jet AM process. Stainless steel and tricalcium phosphate are combined to form a composite and used in different volume fractions to produce parts with varying densities. Layer thickness, sintering time and sintering temperature are varied to study the effect of process parameters on the microstructure, dimensions and mechanical properties of the resulting structure. It is found that the resulting biocomposite can be tailored by varying the process to change its properties and mimic the properties of scaffolds in bone tissue applications.

null

['Rishmawi, I.', 'Salarian, M.', 'Vlasea, M.']

2021-11-09T14:48:28Z

2018

Mechanical Engineering

null

['https://hdl.handle.net/2152/90085', 'http://dx.doi.org/10.26153/tsw/17006']

eng

2018 International Solid Freeform Fabrication Symposium

Open

['binder jetting', 'additive manufacturing', 'irregular iron powder', 'sintering schedule', 'part density']

Binder Jetting Additive Manufacturing of Water-Atomized Iron

Conference paper

https://repositories.lib.utexas.edu//bitstreams/3255ea8e-1696-4572-9ebb-80403c82a6f7/download

University of Texas at Austin

Binder jetting additive manufacturing (BJAM) was deployed to processing of low-cost, water-atomized pure iron powder. Surface morphology and particle size distribution of the powder were fully characterized using scanning electron microscopy (SEM) and particle dynamic image analysis via Retsch Camsizer X2. Cylindrical samples were fabricated, and in the AM process, the effects of powder compaction, layer thickness and liquid binder level on green part density were studied. Density analysis was performed using x-ray computed tomography (µCT). The potential application and future research work will be outlined based on the characterization results.

null

['Caballero, K.', 'Medrano, V.A.', 'Arrieta, E.', 'Sandoval, H.', 'Wicker, R. B.', 'Medina, F.']

2023-04-03T17:42:08Z

2022

Mechanical Engineering

null

['https://hdl.handle.net/2152/117727', 'http://dx.doi.org/10.26153/tsw/44606']

eng

2022 International Solid Freeform Fabrication Symposium

Open

['Metal Additive Manufacturing', 'Binder Jetting', 'Sintering', 'Simufact Additive', 'Shrinkage']

Binder Jetting of 316L process simulation tools evaluation

Conference paper

https://repositories.lib.utexas.edu//bitstreams/99336320-019f-4849-9e81-14de881adc90/download

null

Binder Jetting has become one of the most popular Additive Manufacturing technologies over the years due to its low cost and fast production times, nevertheless this technology has a steep learning curve due to the shrinkage induced to parts during sintering. Since shrinkage is not uniform along the part, it’s hard to efficiently determine what areas will be distorted hence this needs to be taken into consideration when designing a new part and many iterations need to be printed until dimensional accuracy is achieved, as a result production time and cost significantly increase. New Binder Jetting simulation tools are being developed and tested; this software will help the technology be more robust and user-friendly for the industry. The software computes a sintering simulation and can provide displacement results making support positioning more efficient, in addition, newer versions of the software can export a compensated model which will be able to be sintered without supports. To evaluate the simulation software, a dimensional test artifact model was designed and printed, then compared with the software predicted model simulation results. The simulation software was used in an initial evaluation of the test artifact geometry to identify areas of concern in the model and document them so efficiency when predicting material behavior during the sintering process can be evaluated. In addition, an evaluation of the effects of different sintering process parameters on the physical and mechanical properties of the material will be analyzed considering the inert sintering atmosphere of the process. Finally, printing parameters of the machine such as layer thickness, binder saturation, and recoat speed among others will also be evaluated.

null

['Diaz-Moreno, Carlos A.', 'Rodarte, C.', 'Ambriz, S.', 'Bermudez, D.', 'Roberson, D.', 'Terrazas, C.', 'Espalin, D.', 'Ferguson, R.', 'Shafirovich, E.', 'Lin, Y.', 'Wicker, Ryan B.']

2021-11-09T14:46:32Z

2018

Mechanical Engineering

null

['https://hdl.handle.net/2152/90084', 'http://dx.doi.org/10.26153/tsw/17005']

eng

2018 International Solid Freeform Fabrication Symposium

Open

['ceramics', 'aluminum nitride', '3D components fabrication', 'thermal conductivity', 'binder jetting', 'additive manufacturing']

Binder Jetting of High Temperature and Thermally Conductive (Aluminum Nitride) Ceramic

Conference paper

https://repositories.lib.utexas.edu//bitstreams/a7960e4c-eca7-48e4-a4f7-1da3b5a46351/download

University of Texas at Austin

This work reports on the novel fabrication of aluminum nitride (AlN) complex components using binder jetting, on the use of sintering and hot isostatic pressing (HIPing) to increase their density, and on the characterization of the printed material, including thermal conductivity. The HIPing parameters employed were a temperature of 1900 °C using a rich nitrogen atmosphere at a pressure of 30,000 psi during 8 h. Results show that the printed and HIPed AlN components had a 1.96 g/cm3 (60.12%) density when compared to theoretical values. The thermal conductivity for densified and HIPed components was measured in the range from 23 °C to 500 °C resulting in values from 4.82 W/m*K to 3.17 W/m*K, respectively. Characterization using scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction was used to investigate the ceramic structural morphology of the sintered and HIPed material, its chemical composition, and crystal structure of the binder jetting manufactured AlN components.

null

['Ruprecht, John', 'Agarwal, Kuldeep', 'Ahmed, Shaheen']

2021-11-16T16:05:12Z

2019

Mechanical Engineering

null

['https://hdl.handle.net/2152/90326', 'http://dx.doi.org/10.26153/tsw/17247']

eng

2019 International Solid Freeform Fabrication Symposium

Open

['binder saturation', 'layer thickness', 'drying time', 'dimensional tolerance', 'density', 'cobalt chrome', 'tricalcium phosphate', 'biocomposite']

Binder Saturation, Layer Thickness, Drying Time and Their Effects on Dimensional Tolerance and Density of Cobalt Chrome - Tricalcium Phosphate Biocomposite

Conference paper

https://repositories.lib.utexas.edu//bitstreams/2c4450a0-4676-4753-a451-d235a2c2cec8/download

University of Texas at Austin

Traditional metals such as stainless steel, titanium and cobalt chrome are used in biomedical applications (implants, scaffolds etc.) but suffer from issues such as osseointegration and compatibility with existing bone. One way to improve traditional biomaterials is to incorporate ceramics with these metals so that their mechanical properties can be similar to cortical bones. Tricalcium phosphate is such a ceramic with properties so that it can be used in human body. This research explores the use of binder jetting based additive manufacturing process to create a novel biocomposite made of cobalt chrome and tricalcium phosphate. Experiments were conducted and processing parameters were varied to study their effect on the printing of this biocomposite. Layer thickness, binder saturation and drying time affected the dimensional tolerance and the density of the green samples. This effect is important to understand so that the material can be optimized for use in specific applications.

null

['Bai, Yun', 'Williams, Christopher B.']

2021-11-02T14:55:08Z

2017

Mechanical Engineering

null

https://hdl.handle.net/2152/89818

eng

2017 International Solid Freeform Fabrication Symposium

Open

['binder jetting', 'nanoparticles', 'inkjet printing', 'sintering', 'copper']

Binderless Jetting: Additive Manufacturing of Metal Parts via Jetting Nanoparticles

Conference paper

https://repositories.lib.utexas.edu//bitstreams/199dbb02-230a-4e60-a674-b8ebf54da9ab/download

University of Texas at Austin

Binder Jetting AM has been used to fabricate metal parts by first jetting a binder into powder bed; the resulting green part is then thermally post-processed wherein the binder is removed and the metal particles are sintered. In this work, the authors replace conventionally-used polymeric binders with nanoparticle suspensions as a means for binding metal powder bed particles together. After being deposited into the powder particles’ interstices, the jetted nanoparticles are sintered at a low temperature via a heated powder bed to provide strength to the printed green part. Regions of the powder bed that do not receive the jetted nanoparticle suspension remain as loose powder as the sintering temperature of the nanoparticles is significantly lower than the larger powder bed particles. The concept of printing metal by jetting a nanoparticle binder made of the same material is demonstrated in the context of copper through printing copper parts with satisfactory green strength.

null

['Kruth, J. P.', 'Mercelis, P.', 'Froyen, L.', 'Rombouts, Marleen']

2019-12-05T17:23:45Z

2004

Mechanical Engineering

null

['https://hdl.handle.net/2152/78651', 'http://dx.doi.org/10.26153/tsw/5707']

eng

2004 International Solid Freeform Fabrication Symposium

Open

Selective Laser

Binding Mechanisms in Selective Laser Sintering and Selective Laser Melting

Conference paper

https://repositories.lib.utexas.edu//bitstreams/d3cc6586-8609-4387-8b0f-d5ebbf5a91d6/download

null

Layer Manufacturing (LM) technologies like Selective Laser Sintering (SLS) were developed in the late 80’s as techniques for Rapid Prototyping (RP). Today, SLS - as well as its derived technology Selective Laser Melting (SLM) - is used as well for prototyping, tooling and manufacturing purposes. This widening of applications is caused mainly by the possibility to process a large variety of materials, resulting in a broad range of physical and mechanical properties. This paper presents a survey of the various binding mechanisms in SLS and SLM, which are responsible for the broad range of materials and applications. Basic binding mechanisms involve solid state sintering, chemically induced binding, liquid phase sintering, partial melting and full melting. Many subcategories can be distinguished based on the type of structural or binder powder composition: single component powder grains (single material or alloy), composite powder grains, mixtures of different powder grains, distinct binder material (sacrificial or permanent), etc. The paper will explain how these binding mechanisms apply for sintering various types of materials: plastics, metal, ceramics and composites (e.g. glass reinforced polymers, cermets, hardmetals, etc.). It gives a survey of research done at the University of Leuven, Belgium, as well as at other European and non-European organizations.

null

['Jameekornkul, P.', 'Panesar, A.']

2024-03-27T03:37:55Z

2023

Mechanical Engineering

null

['https://hdl.handle.net/2152/124470', 'https://doi.org/10.26153/tsw/51078']

en_US

2023 International Solid Freeform Fabrication Symposium

Open

['additive manufacturing', 'bouligand fiber arrangement', 'honeycomb structure']

BIO-INSPIRED AM STRUCTURE WITH CARBON FIBRE REINFORCEMENT

Conference paper

https://repositories.lib.utexas.edu//bitstreams/5bfd2951-ff59-4ac7-b35f-3cf905d01146/download

University of Texas at Austin

This study presents a novel design approach that introduces the bouligand fibre arrangement in a honeycomb structure. This design is made possible by utilising AM technology which allows for the realisation of complex design whilst ensuring precise control for fibre placement. Reinforced honeycomb structures with varied incrementally twisted pitch angle of 0°,1.25°,5° and 15° were successfully fabricated and tested under outof-plane compression. Among the tested angles, the honeycomb structure oriented at 1.25° exhibited higher peak load and higher specific energy absorption. Unlike the original untwisted honeycomb, the bio-inspired honeycomb showed no noticeable buckling or delamination at the mid-plane, which may be due the microcracking or resulting from a delay in crack propagation. However, the precise relationship between pitch angle and honeycomb properties requires further investigation across a wider range of pitch angle with more focus understanding the fracture propagation in fibre arrangement. Overall, the preliminary results indicate that the proposed bio-inspired AM design present a promising approach to enhance the properties of honeycombs and afford the flexibility to improve toughness and energy absorption capabilities.

null

['Guo, Nannan', 'Leu, Ming C.', 'Wu, Maoliang']

2021-10-05T14:39:49Z

8/17/11

Mechanical Engineering

null

['https://hdl.handle.net/2152/88382', 'http://dx.doi.org/10.26153/tsw/15321']

eng

2011 International Solid Freeform Fabrication Symposium

Open

['fuel cells', 'polymer electrolyte membrane', 'flow fields', 'bipolar plate', 'finite element modeling']

Bio-Inspired Design of Bipolar Plate Flow Fields for Polymer Electrolyte Membrane Fuel Cells

Conference paper

https://repositories.lib.utexas.edu//bitstreams/142c716a-8625-4cbd-a51c-b749d74fe960/download

University of Texas at Austin

The flow field of a bipolar plate distributes hydrogen and oxygen for polymer electrolyte membrane (PEM) fuel cells and removes the produced water from the fuel cells. It greatly influences the performance of fuel cells, especially regarding reduction of mass transport loss. Flow fields with good gas distribution and water removal capabilities reduce the mass transport loss, thus allowing higher power density. Inspired by natural structures such as veins in tree leaves and blood vessels in lungs, which efficiently feed nutrition from one central source to large areas and are capable of removing undesirable by-products, a mathematic model has been developed to optimize the flow field with minimal pressure drop, lowest energy dissipation, and uniform gas distribution. The model can be used to perform optimal flow field designs, leading to better fuel cell performance for different sizes and shapes of bipolar plates. Finite element modeling (FEM) based simulations and in-situ experiments were conducted to verify some of the flow field designs obtained using the developed mathematic model.

null

['Lee, G.', 'Barlow, J.W.', 'Fox, W.C.', 'Aufdermorte, T.B.']

2018-11-08T19:14:05Z

1996

Mechanical Engineering

doi:10.15781/T2S46HR8S

http://hdl.handle.net/2152/69907

eng

1996 International Solid Freeform Fabrication Symposium

Open

['SLS', 'MRI', 'reconstruction']

Biocompatibility of SLS-Formed Calcium Phosphate Implants

Conference paper

https://repositories.lib.utexas.edu//bitstreams/907f6f0a-3cf2-4291-8891-429666d4a170/download

null

A method for fabricating artificial calcium phosphate bone implants by the Selective Laser Sintering (SLS) process has been developed that can fabricate complex and delicate calcium phosphate bone facsimiles from a variety of data inputs including Computed Tomography(CT) files (1). This paper discusses two in vivo biocompatibility studies of SLS-formed calcium phosphate implants in both rabbits and dogs. Histologic analysis shows a high degree of biocompatibility and bone ingrowth in both studies.

null

['He, Yinfeng', 'Kilsby, Sam', 'Tuck, Chris', 'Wildman, Ricky', 'Christie, Steven', 'Yang, Hongyi', 'Edmondson, Steven']

2021-10-18T21:21:06Z

2014

Mechanical Engineering

null

https://hdl.handle.net/2152/89249

eng

2014 International Solid Freeform Fabrication Symposium

Open

['biodegradable polycaprolactone based ink', 'biodegradable polycaprolactone', '3D inkjet printing', 'Additive Manufacturing', 'biomedical applications']

A Biodegradable Polycaprolactone Based Ink Developed for 3D Ink Jetting

Conference paper

https://repositories.lib.utexas.edu//bitstreams/992bc183-550a-476b-b002-195c4048623a/download

University of Texas at Austin

Biomedical applications are one of the driving forces for Additive Manufacturing, however to extend the range of applications and markets new materials are required. A new type of biodegradable Polycaprolactone (PCL) based ink that is suitable for 3D inkjet printing was successfully developed. UV curable PCL was synthesized and mixed with Poly(ethylene glycol) di-acrylated (PEGDA) to prepare an ink with suitable viscosity for inkjet printing. Their mechanical properties as well as the printing accuracy were measured by nano-indentation and scanning electron microscopy. Post curing was applied to printed samples in order to study how post curing may influence sample properties. It was found that within 30min post-curing period, the sample’s surface which is direct illuminated by UV light increased from 31.22MPa to 70.20MPa while the bottom surface showed less incensement from 34.9MPa to 39.8MPa.

null

['Starly, B.', 'Lau, A.', 'Sun, W.', 'Lau, W.', 'Bradburyq, T.']

2020-02-17T15:36:54Z

2004

Mechanical Engineering

null

['https://hdl.handle.net/2152/80012', 'http://dx.doi.org/10.26153/tsw/7037']

eng

2004 International Solid Freeform Fabrication Symposium

Open

Interior Architecture Design

Biomimetic Design and Fabrication of Interior Architecture of Tissue Scaffolds Using Solid Freeform Fabrication

Conference paper

https://repositories.lib.utexas.edu//bitstreams/85971b3e-5d43-4c7e-8621-6836b4756151/download

null

Modeling, design and fabrication of tissue scaffolds with intricate architecture, porosity and pore size for desired tissue properties presents a challenge in tissue engineering. This paper will present the details of our development in designing and fabrication of the interior architecture of scaffolds using a novel design approach. The Interior Architecture Design (IAD) approach seeks to generate scaffold layered freeform fabrication tool path without forming complicated 3D CAD scaffold models. This involves: applying the principle of layered manufacturing to determine the scaffold individual layered process planes and layered contour; defining the 2D characteristic patterns of the scaffold building blocks (unit cells) to form the Interior Scaffold Pattern; and the generation of process tool path for freeform fabrication of these scaffolds with the specified interior architecture. Feasibility studies applying the IAD algorithm to example models and the generation of fabrication planning instructions will be presented.

null

['Delwiche, Maia', 'Obielodan, John']

2023-02-10T13:51:54Z

2022

Mechanical Engineering

null

['https://hdl.handle.net/2152/117446', 'http://dx.doi.org/10.26153/tsw/44327']

eng

2022 International Solid Freeform Fabrication Symposium

Open

['Additive manufacturing', 'Biopolymer', 'Dairy', 'Casein', 'Polymers']

Biopolymer Composites with Dairy Protein for Use in Additive Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/020f269d-1ed1-47e7-84f1-da571b902c97/download

null

As the popularity and versatility of additive manufacturing grows, so does interest in developing new materials, including biopolymers. Casein is a protein found in dairy and historically, has been used in food applications, but its use as a biomaterial for engineering structures is less common. This study investigates the development of composite materials for additive manufacturing with casein as a biomaterial filler. To observe the effects of casein on material properties, vat photopolymerization-based and fused filament fabrication-based matrix materials were combined with different weight fractions of casein. Test samples were fabricated to evaluate tensile properties. Test results show a maximum increase of 4% for FFF and 34% for SLA in the stiffness of the materials with casein compared to the neat matrix materials. However, the composite materials showed between 12% and 54% reductions in ductility, and marginal decreases in tensile strengths. The preliminary results indicate viability and prompt further investigation into casein-polymer composites for additive manufacturing.

null

['Hoeges, S.', 'Lindner, M.', 'Meiners, W.', 'Smeets, R.']

2021-10-04T19:58:13Z

9/23/10

Mechanical Engineering

null

['https://hdl.handle.net/2152/88330', 'http://dx.doi.org/10.26153/tsw/15269']

eng

2010 International Solid Freeform Fabrication Symposium

Open

['bioresorbable implants', 'bone implants', 'additive manufacturing', 'Selective Laser Melting', 'bone surgery']

Bioresorbable Implants using Selective Laser Melting

Conference paper

https://repositories.lib.utexas.edu//bitstreams/e45a9a14-577d-4df0-be76-1d395bbcc2fb/download

University of Texas at Austin

Using bioresorbable materials implants can be manufactured which dissolve in the human body and are replaced by natural bone structure. For large implants an interconnecting porous structure needs to be integrated in the implant for a good vascularisation. Using additive manufacturing technology these internal structures can be directly manufactured. The structure can be designed by consequent following the guidelines of the medical expert. This paper describes the development of Selective Laser Melting to process bioresorbable materials Poly(D,L-lactide) and B-Tricalciumphosphate. The properties of the parts concerning microstructure, mechanical and biological properties after processing are analyzed in laboratory and animal tests. Possible applications are demonstrated and include individual bone substitute implants in cranio-maxillofacial surgery.

null

['Liu, J.', 'Fearon, E.', 'Edwardson, S.P.', 'Dearden, G.']

2021-11-04T14:12:12Z

2017

Mechanical Engineering

null

https://hdl.handle.net/2152/89965

eng

2017 International Solid Freeform Fabrication Symposium

Open

['blown powder laser cladding', 'processing parameters', 'isotropic material', 'build height', 'powder delivery rate', 'additive manufacturing']

Blown Powder Laser Cladding with Novel Processing Parameters for Isotropic Material Properties

Conference paper

https://repositories.lib.utexas.edu//bitstreams/2ebca7c3-6294-449d-948f-fef4e264b524/download

University of Texas at Austin

A limitation for blown powder laser additive manufacturing in many applications is the material properties of parts made tend to show anisotropy due to directional solidification of the microstructure. Recent work reported here has identified novel low power processing conditions that yield equiaxed grain structures in 316L stainless steel and thus potentially eliminate material anisotropy. Initial observations show that the process window is affected by build height, substrate choice, powder, powder delivery rates, laser power and processing speed. A system has been developed to give precision layer height control via nozzle design and low powder delivery rates through an in-house design of powder hopper. Mechanical tests have been conducted under the novel processing parameters. Large amounts and uniform distribution of equiaxed structures compared to standard process conditions in 316L are found significantly. Moreover, cladding has been successfully produced with significantly low power around 350W, thus potentially improving process efficiency and set-up cost.

null

['Sriraman, M.R.', 'Hiromichi, Fujii', 'Gonser, Matt', 'Babu, S.S.', 'Short, Matt']

2021-09-30T15:27:12Z

9/23/10

Mechanical Engineering

null

['https://hdl.handle.net/2152/88263', 'http://dx.doi.org/10.26153/tsw/15204']

eng

2010 International Solid Freeform Fabrication Symposium

Open

['Very High Power Ultrasonic Additive Manufacturing', 'aluminum alloys', 'copper alloys', 'layer bonding']

Bond Characterization in Very High Power Ultrasonic Additive Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/f1996184-5392-463a-b2bb-abc35960ffd3/download

University of Texas at Austin

Solid parts were produced by Very High Power Ultrasonic Additive Manufacturing (VHP-UAM) at room temperature using 150 μm thick tapes of 6061 aluminum and 110 copper alloys. Processing was done at 20 kHz frequency over a range of parameters (26 –36 μm vibration amplitude, 5.6 – 6.7 kN normal force, and 30.5 - 35.5 mm/s travel speed). Softening of materials (up to about 14% in 6061 Al and 23% in 110 Cu) was noted facilitating enhanced plastic flow and a reduction in interfacial voids. Evolution of fine recrystallized grains (0.3-4 μm in 6061 Al and 0.3-10 μm in 110 Cu) from an initial coarser grain structure (up to 8 μm in 6061 Al and 25 μm in Cu) was observed at the build interface regions. Bonding between layers in both materials seems to have occurred by dynamic recrystallization and movement of grain boundaries across the interface. The energy required for the above physical processes is derived from interfacial adiabatic plastic deformation heating.

null

['Walczyk, Daniel F.', 'Dolar, Nathanael Y.']

2018-11-29T21:00:36Z

1997

Mechanical Engineering

doi:10.15781/T2QR4P95D

http://hdl.handle.net/2152/70344

eng

1997 International Solid Freeform Fabrication Symposium

Open

['welding', 'laminations']

Bonding Methods for Laminated Tooling

Conference paper

https://repositories.lib.utexas.edu//bitstreams/1be7e4e5-c0bb-4ae3-9353-0aef1950a707/download

null

Laminated tooling consists of an array of stacked laminations that are mechanically clamped or bonded together, depending on the requirements of the manufacturing process. Various manufacturing processes that can benefit from tooling constructed oflaminations include sheet metal forming, thermoforming, composites molding, metal extrusion, injection molding, resin transfer molding, and compression molding. When bonding of the laminations is required (e.g., incorporation of conformal cooling passages for injection molding temperature control) then laminations can be joined together by diffusion bonding, brazing and using adhesives. However, for a tooling engineer to effectively design a laminated tool, the physical and mechanical properties of these joints must be known. Consequently, a set of experiments is outlined for determining the tensile, shear, and peel strengths, tensile and shear elastic moduli, thermal contact resistance, and specific permeability (for gasses or liquids) ofthe aforementioned bonded joints for both steel and aluminum laminations. Some preliminary results with aluminum and future work are presented.

null

['Ott, M.', 'Meihöfener, N.', 'Koch, R.']

2023-03-30T16:06:43Z

2022

Mechanical Engineering

null

['https://hdl.handle.net/2152/117696', 'http://dx.doi.org/10.26153/tsw/44575']

eng

2022 International Solid Freeform Fabrication Symposium

Open

Additive manufacturing

Boosting artificial intelligence in design processes by the use of additive manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/c06599a6-b454-48f6-a52a-3e09575c2438/download

null

Additive manufacturing offers the option of converting digital prototypes into real structures as quickly as possible by the special property of tool-free manufacturing. However, this process can only be used at optimum speed if bottlenecks can be effectively avoided. One of these constraints is the design process. Although modern CAD systems allow a significant increase in many areas, this always requires a person with specific skills (e.g. engineer). In the field of AM in particular, more and more powerful software solutions have recently been published which accelerate the Design for Additive Manufacturing, including most CAD-tasks. In many areas, therefore, attempts are already made to automate relevant design steps as much as possible, more and more using neural networks and artificial intelligence. This paper presents how and why such techniques can be used to generate three-dimensional structures quickly and efficiently in cases of deep generative design tasks.

null

['Lipton, Jeffrey I.', 'Cohen, Daniel', 'Lipson, Hod']

2021-09-29T18:04:36Z

9/15/09

Mechanical Engineering

null

['https://hdl.handle.net/2152/88203', 'http://dx.doi.org/10.26153/tsw/15144']

eng

2009 International Solid Freeform Fabrication Symposium

Open

['brick printing', 'modular architectural elements', 'embedded systems', 'open-architecture SFF']

Brick Printing: Freeform Fabrication of Modular Architectural Elements with Embedded Systems

Conference paper

https://repositories.lib.utexas.edu//bitstreams/72ca5735-3301-4bab-89e8-83ebca726a1e/download

University of Texas at Austin

We propose the use of modular, printed bricks to enable the integration of building systems and various processing techniques through the use of scalable printer platforms. This is enabled by a novel material platform comprised of clay, gypsum cement, FabEpoxy™, and SS-26F conductive silicone. On an open-architecture SFF system, a segment of cement wall with embedded electrical and fluidic conduits and various processing techniques was fabricated. Electrical and fluidic tolerances were comparable to traditionally constructed systems.

null

['Luo, Junjie', 'Bender, Theresa', 'Bristow, Douglas A.', 'Landers, Robert G.', 'Goldstein, Jonathan T.', 'Urbas, Augustine M.', 'Kinzel, Edward C.']

2021-10-28T14:31:28Z

2016

Mechanical Engineering

null

https://hdl.handle.net/2152/89650

eng

2016 International Solid Freeform Fabrication Symposium

Open

['bubble formation', 'bubble entrapment', 'borosilicate glass', 'additive manufacturing']

Bubble Formation in Additive Manufacturing of Borosilicate Glass

Conference paper

https://repositories.lib.utexas.edu//bitstreams/b97f2f04-6bed-4f4d-bbad-32cbae205df8/download

University of Texas at Austin

Entrapped bubbles are an important problem in conventional glass manufacturing. It is also a significant factor determining the quality of glass products produced using additive manufacturing (AM). This paper reports on the bubble formation and entrapment in filament-fed AM printing of borosilicate glass. This process involves maintaining a local molten region using a CO2 laser. A 2 mm filament is fed continuously into the molten region while CNC stages position the workpiece relative to the laser and filament feed. Two different bubble regimes are identified in experiments with borosilicate glass. These regimes can be related to different physical phenomena, specifically, bubble entrapment at defects in the filaments and bubble formation due to reboil. These can be overcome by selecting defect free filaments and by minimizing the temperature inside the molten region to prevent breaking down the glass. Understanding these mechanisms allows bubble-free glass to be printed. Finally, residual stress in the deposited glass pieces is removed using post-deposition annealing and validated using a polariscope.

null

['Roschli, Alex', 'Post, Brian K.', 'Atkins, Celeste', 'Stevens, Adam G.', 'Chesser, Phillip', 'Zaloudek, Kristin']

2023-01-27T13:59:03Z

2022

Mechanical Engineering

null

['https://hdl.handle.net/2152/117333', 'http://dx.doi.org/10.26153/tsw/44214']

eng

2022 International Solid Freeform Fabrication Symposium

Open

['build plate', 'build surface', 'extrusion', '3D printer design']

Build Plate Design for Extrusion-Based Additive Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/eee89ba5-c62e-4bfc-a37a-b274a21b27ee/download

null

A fundamental part of machine design for large format polymer extrusion-based additive manufacturing (AM) systems is the substrate where the object is to be constructed, often referred to as the build plate. A good build plate is imperative for a successful build as it is used for supporting and positioning the part during the entire construction. For planar 3D printing, this build plate needs to be flat and in-plane with the X/Y motion of the 3D printer. Additional functionality can include heaters for preventing delamination or warping, vacuum to help prevent warping, removable build surfaces for quick part removal, and mounting features for helping position a part for subtractive operations. This paper reviews existing build plate designs and discusses the design considerations and materials for build plate fabrication.

null

['McClurkin, Joel E.', 'Rosen, David W.']

2018-12-07T16:06:52Z

1997

Mechanical Engineering

doi:10.15781/T2HD7PC8K

http://hdl.handle.net/2152/71442

eng

1997 International Solid Freeform Fabrication Symposium

Open

['SLA', 'Build Style Optimization']

Build Style Decision Support for Stereolithography

Conference paper

https://repositories.lib.utexas.edu//bitstreams/cbe2b51b-3e0e-4fbf-ab0b-a15815fd48d8/download

null

When building parts in a stereolithography apparatus (SLA), the user is faced with many decisions regarding how the part will be built. The quality of the build can be controlled by the user via changing one of several build style variables, including part orientation, cross sectional layer thickness, and laser hatch density. A user will probably have preferences for the part build (Le., accuracy or speed), but may not understand how to vary the build style variables to produce the desired results. A method based on response surface methodology and multi-objective decision support is described in this paper for relating build goals to three build style variables, and the use ofthese relationships in providing decision support for building a part on a SLA. The method is applied to the build style of a circuit breaker handle.

null

['Mensing, G.', 'Gibson, I.']

2019-02-22T19:58:47Z

1998

Mechanical Engineering

null

['https://hdl.handle.net/2152/73468', 'http://dx.doi.org/10.26153/tsw/618']

eng

1998 International Solid Freeform Fabrication Symposium

Open

['rapid prototyping systems', 'StereoLithography']

Build Time Estimations for Large Scale Modelling

Conference paper

https://repositories.lib.utexas.edu//bitstreams/e9ccdbc7-9a63-431f-92ca-a285750f03c1/download

null

Achieving speedy results in model making is very much desired if not a necessity in ahnost any manufacturing industry. There is no doubt that rapid prototyping contributes to this process. It is generally considered that when compared to conventional machining techniques like nlilling, the current rapid prototyping systems appear to be much faster. This is certainly true for complex,slnall objects. I-Iowever, this is not alwaysa,pplicable to simple, large and bulky parts. There are a number of projects and systems concentrating on the fabrication of large models. Work is being carried out at the University ofHong Kong, using milling. along with slicing technology. This.report compares some ofthe rapid prototyping systems witl1milling. Milling is an established technology and recent developments in materials and nlachines used in Inilling nlake it a good alternative to rapid prototyping when itcomes to largesyale nl0delling.

null

['Li, Yingqi', 'Shen, Yiyu', 'Leu, Ming C.', 'Tsai, Hai-Lung']

2021-11-02T19:46:04Z

2017

Mechanical Engineering

null

https://hdl.handle.net/2152/89880

eng

2017 International Solid Freeform Fabrication Symposium

Open

['metallic glass', 'titanium', 'laser welding', 'embrittlement', 'additive manufacturing']

Building Zr-Based Metallic Glass Part on Ti-6Al-4V Substrate by Laser-Foil-Printing Additive Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/facfccd8-bb78-4ef6-b4b6-3892c4656cb0/download

University of Texas at Austin

Through using Zr intermediate layers, Zr52.5Ti5Al10Ni14.6Cu17.9 metallic glass (MG) parts are successfully built on Ti-6Al-4V substrate by laser-foil-printing (LFP) additive manufacturing technology in which MG foils are laser welded layer-by-layer onto the substrate. The printed MG part is free of porosity, cracking and crystallization, and its properties are very similar to the original MG material. The Zr intermediate layers are aimed at preventing direct interaction between the first layer of MG foil and the Ti substrate; otherwise, the welded MG foils would peel off from the substrate due to the formation of brittle intermetallic compounds. With the use of Zr intermediate layers, the bonding strength of the printed MG part and the Ti substrate can reach 758 MPa owing to the formation of α-Zr phase.

null

['Choi, Sangeun', 'Hebbar, Ravi', 'Zheng, Yong', 'Newman, Wyatt S.']

2018-12-07T16:11:52Z

1997

Mechanical Engineering

doi:10.15781/T2804Z53B

http://hdl.handle.net/2152/71444

eng

1997 International Solid Freeform Fabrication Symposium

Open

['CAD', 'SDM']

CAD and Control Technologies for Computer-Aided Manufacturing of Laminated Engineering Materials

Conference paper

https://repositories.lib.utexas.edu//bitstreams/74d442b8-0888-4062-8bac-8b51d3cd162a/download

null

This paper presents recent progress in software, material handling and tangent-cutting control in support of Computer-Aided Manufacturing of Laminated Engineering Materials(CAM-LEM). Progress in CAD focuses on the definition of a new layered file format for describing 3-D solids in terms of thick slabs with ruled-surface edges. For material handling, we present new algorithms for automatic generation of mask hole patterns used in selective-area vacuum gripping, which is required for our laminated assembly process. Finally, we present recent results of object fabrication using thick-slab, tangent-cut layers

null

['Koch, P.', 'Korn, H.', 'Kordass, R.', 'Holtzhausen, S.', 'Schoene, C.', 'Mueller, B.', 'Stelzer, R.']

2021-11-09T20:22:10Z

2018

Mechanical Engineering

null

['https://hdl.handle.net/2152/90156', 'http://dx.doi.org/10.26153/tsw/17077']

eng

2018 International Solid Freeform Fabrication Symposium

Open

['CAD-based workflow', 'CAD', 'mechanical characterization', 'lattice structures', 'laser beam melting', 'additive manufacturing']

A CAD-Based Workflow and Mechanical Characterization for Additive Manufacturing of Tailored Lattice Structures

Conference paper

https://repositories.lib.utexas.edu//bitstreams/c2854ec4-ff96-42cc-8521-536b58fcf0ac/download

University of Texas at Austin

Lattice structures are highly recommended for lightweight applications and cost reduction in additive manufacturing (AM). Currently, parts with lattice structures are still mainly used for illustrative purposes and rarely in industrial products. One important reason is that, due to their high dependency on macro- and micro-geometry, the mechanical properties of manufactured structures are difficult to predict. Thus, even and precise struts are needed. In this paper, a workflow for fabrication of lattice structures with strut-diameters from 150 µm to 400 µm on commercial laser beam melting (LBM) systems is presented. Based on a CAD-integrated user-interface for lattice design, a customized slicing algorithm determines database-aided suitable exposure parameters which ensure that the properties of the manufactured struts will just be as specified upon design. Subsequently, compression tests are performed in order to verify the established workflow. The developed tool enables designers to integrate AM-specific geometries into their components with little specific experience in AM.

null

['Quigley, Tiffany', 'Penney, Joshua', 'Goodspeed, Devon', 'Cornelius, Aaron', 'Hamel, William', 'Schmitz, Tony', 'Jared, Bradley']

2023-01-26T14:58:16Z

2022

Mechanical Engineering

null

['https://hdl.handle.net/2152/117313', 'http://dx.doi.org/10.26153/tsw/44194']

eng

2022 International Solid Freeform Fabrication Symposium

Open

WAAM

CAD-to-Scan Planning for Hybrid Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/88468c5b-da74-442e-9dca-41587730f8c5/download

null

The University of Tennessee, Knoxville (UT) has developed a hybrid manufacturing work cell incorporating wire-arc additive manufacturing (WAAM), fringe projection scanning and 5- axis machining. Integrating metrology into the hybrid manufacturing work cell enables optimization of printed part placement for machining and/or supplementary material, when necessary, via additional deposition. This presentation will explore path planning for efficient imaging of printed geometries. The acquired scans are then polygonized and compared to the desired geometry which is utilized in defining machining areas with excess material or underbuilt areas for additional material deposition via gas metal arc welding (GMAW).

null

['Zhou, Chi', 'Chen, Yong']

2021-09-28T18:45:32Z

9/15/09

Mechanical Engineering

null

['https://hdl.handle.net/2152/88150', 'http://dx.doi.org/10.26153/tsw/15091']

eng

2009 International Solid Freeform Fabrication Symposium

Open

['Solid Freeform Fabrication', 'large-area mask projection stereolithography', 'digital light processing', 'calibration']

Calibrating Large-area Mask Projection Stereolithography for Its Accuracy and Resolution Improvements

Conference paper

https://repositories.lib.utexas.edu//bitstreams/94990696-ae14-459e-bf8d-91514dfb1d16/download

University of Texas at Austin

Solid freeform fabrication (SFF) processes based on mask image projection such as digital micro-mirror devices (DMD) have the potential to be fast and inexpensive. More and more research and commercial systems have been developed based on such digital devices. However, a digital light processing (DLP) projector based on DMD has limited resolution and certain image blurring. In order to use a DLP projector in the large-area mask projection stereolithography, it is critical to plan mask images in order to achieve high accuracy and resolution. Based on our previous work on optimized pixel blending, we present a calibration method for capturing the non-uniformity of a projection image by a low cost off-the-shelf DLP projector. Our method is based on two calibration systems, a geometric calibration system that can calibrate the position, shape, size, and orientation of a pixel and an energy calibration system that can calibrate the light intensity of a pixel. Based on both results, the light intensity at various grayscale levels can be approximated for each pixel. Developing a library of such approximation functions is critical for the optimized pixel blending to generate a better mask image plan. Experimental results verify our calibration results.

null

['Torabi, Payman', 'Petros, Matthew', 'Khoshnevis, Behrokh']

2021-10-12T22:20:23Z

2014

Mechanical Engineering

null

['https://hdl.handle.net/2152/88754', 'http://dx.doi.org/10.26153/tsw/15688']

eng

2014 International Solid Freeform Fabrication Symposium

Open

['Selective Inhibition Sintering', 'Additive Manufacturing', 'piezo-electric printhead', 'metal parts', 'Design of Experiments']

Calibration of a Piezo-Electric Printhead in the Selective Inhibition Sintering (SIS) Process for Fabrication of High Quality Metallic Parts

Conference paper

https://repositories.lib.utexas.edu//bitstreams/30e6d444-6ac0-4faf-bb6d-c4b2533c28ed/download

University of Texas at Austin

Selective Inhibition Sintering (SIS) is a disruptive Additive Manufacturing process capable of printing parts from polymers, metals and ceramics. In this paper the application of a commercial piezo-electric printhead in SIS-metal is studied. This replaces the single-nozzle solenoid valve previously used in the process and allows the fabrication of high quality metallic parts due to smaller droplet sizes as well as high resolution printing mechanisms. A Design of Experiments (DoE) approach has been utilized to study the effects of important factors in printing the inhibitor. These factors include: composition of the inhibitor, quality of the print, and amount of fluid deposited for each layer. Based on the results of these experiments, parameters have been identified for the creation of highly accurate three-dimensional parts.

null