ccm/sff-papers · Datasets at Hugging Face

['Hafkamp, Thomas', 'van Baars, Gregor', 'de Jager, Bram', 'Etman, Pascal']

2021-11-02T19:25:02Z

2017

Mechanical Engineering

null

https://hdl.handle.net/2152/89873

eng

2017 International Solid Freeform Fabrication Symposium

Open

['recoating', 'ceramic-filled resin', 'ceramics', 'vat photopolymerization', 'stereolithography']

A Trade-Off Analysis of Recoating Methods for Vat Photopolymerization of Ceramics

Conference paper

https://repositories.lib.utexas.edu//bitstreams/79477c5f-81b5-4340-845b-fa114f24de55/download

University of Texas at Austin

Technical ceramic parts can be produced by curing ceramic-filled resins in the vat photopolymerization (stereolithography) process. Scaling up to larger ceramic product sizes and higher product quality calls for the integration of more sensing, actuation and closed-loop control solutions while taking a systems engineering approach. This paper gives a comprehensive overview of methods to deposit a layer of (ceramic-filled) resin, better known as recoating. The aim of this work is to perform a trade-off analysis of recoating methods to enable the selection of the method that best meets the requirements for scaling up the printable object size in the ceramic vat photopolymerization process.

null

['Menon, Nandana', 'Mondal, Sudeepta', 'Basak, Amrita']

2023-02-09T15:59:47Z

2022

Mechanical Engineering

null

['https://hdl.handle.net/2152/117437', 'http://dx.doi.org/10.26153/tsw/44318']

eng

2022 International Solid Freeform Fabrication Symposium

Open

machine learning

Transferring Process Mapping Knowledge across SS316L and IN718 in Laser Directed Energy Deposition Using Machine Learning

Conference paper

https://repositories.lib.utexas.edu//bitstreams/193dbadb-817c-44b0-85b7-38b5f9ab8140/download

null

Laser-directed energy deposition additive manufacturing processes have several parameters that impact the melt pool properties, which in turn affect the microstructure of the part. Computational investigations are regularly implemented; however, these investigations must be repeated for each material of interest. In this paper, a transfer learning approach is proposed to address this challenge. Using an analytical model, input-output data pairs are generated for a nickel-based alloy, IN718, and an iron-based alloy, SS316L. A baseline neural network is trained for SS316L. The capability of transfer learning is analyzed with parametric retraining of the percentage of data used and the number of retrained layers of the SS316L baseline network on the IN718 data. With just 10% data and one hidden layer retrained, accuracies above 90% are observed. The results show that the acquired printability knowledge can be transferred across material systems without requiring a significant amount of data for a new material system.

null

['Gomez, Connie', 'Starly, Binil', 'Shokoufandeh, Ali', 'Sun, Wei']

2020-02-27T21:01:31Z

2006

Mechanical Engineering

null

['https://hdl.handle.net/2152/80107', 'http://dx.doi.org/10.26153/tsw/7128']

eng

2006 International Solid Freeform Fabrication Symposium

Open

Computer Aided Tissue Engineering

Transferring Unit Cell Based Tissue Scaffold Design to Solid Freeform Fabrication

Conference paper

https://repositories.lib.utexas.edu//bitstreams/78993294-28e4-4abf-8e19-c98bef1b3fc5/download

null

Designing for the freeform fabrication of heterogeneous tissue scaffold is always a challenge in Computer Aided Tissue Engineering. The difficulties stem from two major sources: 1) limitations in current CAD systems to assembly unit cells as building blocks to form complex tissue scaffolds, and 2) the inability to generate tool paths for freeform fabrication of unit cell assemblies. To overcome these difficulties, we have developed an abstract model based on skeletal representation and associated computational methods to assemble unit cells into an optimized structure. Additionally we have developed a process planning technique based on internal architecture pattern of unit cells to generate tool paths for freeform fabrication of tissue scaffold. By modifying our optimization process, we are able to transfer an optimized design to our fabrication system via our process planning technique.

null

['Aggarangsi, Pruk', 'Beuth, Jack L.', 'Gill, David D.']

2020-02-12T15:44:02Z

2004

Mechanical Engineering

null

['https://hdl.handle.net/2152/79942', 'http://dx.doi.org/10.26153/tsw/6968']

eng

2004 International Solid Freeform Fabrication Symposium

Open

Manufacturing Processes

Transient Changes in Melt Pool Size in Laser Additive Manufacturing Processes

Conference paper

https://repositories.lib.utexas.edu//bitstreams/6e5f93c4-66bd-409d-bc90-4fa25b7e76b8/download

null

['Sigl, M.', 'Lutzmann, S.', 'Zaeh, M.F.']

2020-03-02T15:29:30Z

9/14/06

Mechanical Engineering

null

['https://hdl.handle.net/2152/80133', 'http://dx.doi.org/10.26153/tsw/7154']

eng

2006 International Solid Freeform Fabrication Symposium

Open

electron beam

Transient Physical Effects in Electron Beam Sintering

Conference paper

https://repositories.lib.utexas.edu//bitstreams/b785571b-a4d1-43a7-b22c-fed23b851ba3/download

null

The extensive use of the electron beam in manufacturing processes like welding or perforating revealed the high potentials for also using it for solid freeform fabrication. First approaches like feeding wire into a melt pool have successfully shown the technical feasibility. Among other features, the electron beam exhibits high scanning speed, high power output, and beam density. While in laser-based machines the fabrication is working in a stable way, transient physical effects in the electron beam process can be observed, which still restrict process stability. For instance, a high power input of the electron beam can result in sudden scattering of the metal powder. The authors have developed an electron beam freeform fabrication system and examined the above mentioned effects. Thus, the paper provides methods in order to identify, isolate and avoid these effects, and to finally realize a reproducible process.

null

['Roschli, Alex', 'Borish, Michael', 'White, Liam', 'Adkins, Cameron', 'Atkins, Celeste', 'Barnes, Abigail', 'Post, Brian', 'DiVencenzo, Zac', 'Dwyer, Charlie', 'Rudiak, Gaven', 'Zellers, Brian']

2024-03-26T20:23:20Z

2023

Mechanical Engineering

null

['https://hdl.handle.net/2152/124394', 'https://doi.org/10.26153/tsw/51002']

en_US

2023 International Solid Freeform Fabrication Symposium

Open

['G-code', '3D printer calibration', 'flowrate', 'feedrate', 'bead width']

Transmitting G-Code with Geometry Commands for Extrusion Additive Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/f9dd48c4-3ab0-44dd-bf3c-5c3c451c41b9/download

University of Texas at Austin

G-code refers to text-based commands used to instruct a 3D printer how to construct an object. G-code is generated to represent each toolpath during the slicing process. Each toolpath is represented as a list of points that define the trajectory of the path to be printed. Additional commands are included to define the motion velocity and extrusion rate, called the feeds and speeds. These toolpaths and commands must be generated specific to the machine, material, and calibration settings that will be used during the print. This paper outlines a new approach for the slicing and g-code creation process that eliminates the need for outputting feeds and speeds in the slicing process. Instead, the slicer outputs g-code that defines the desired bead geometry as printed. The 3D printer can then read this geometry data and calculate the necessary feeds and speeds based on internal calibration data to successfully print the object.

null

['Niino, Toshiki', 'Yamada, Hidenori']

2020-02-21T14:43:01Z

8/26/05

Mechanical Engineering

null

['https://hdl.handle.net/2152/80058', 'http://dx.doi.org/10.26153/tsw/7080']

eng

2005 International Solid Freeform Fabrication Symposium

Open

solid freeform fabrication

Transparentization of SLS Processed SMMA Copolymer Parts by Infiltrating a Thermosetting Epoxy Resin with Tuned Refractive Index

Conference paper

https://repositories.lib.utexas.edu//bitstreams/9fc67b6c-962c-4213-91cd-3f2e866924d5/download

null

Selective laser sintering is quite advantageous to build complicated tubular structures such as intake manifolds of automotive engines because of its ability of building undercut structures without using support ribs. On the other hands, inevitable opacity of the parts obtained from the process is lowering its advantage when we need to observe inside of the parts. A technology that can transparentize SLS processed parts by infiltrating curable resin with tuned refractive index was introduced by the authors in 2004, and in this paper, several modifications are added on material, process parameters and their control accuracies to improve clarity of obtained parts. As a result of these modifications, haze of the processed part was reduced by a factor of 40% reaching the lowest value of 20% through a plate with thickness of 5mm.

null

['Weaver, J.M.', 'Patternson, C.']

2021-12-07T18:10:25Z

2021

Mechanical Engineering

null

['https://hdl.handle.net/2152/90743', 'http://dx.doi.org/10.26153/tsw/17662']

eng

2021 International Solid Freeform Fabrication Symposium

Open

['TRIZ', 'theory of inventive problem solving', 'design for additive manufacturing']

A Triz-Based Analysis of the Fundamental Limits of Fused Filament Fabrication

Conference paper

https://repositories.lib.utexas.edu//bitstreams/6a4e6921-e7d7-4e9f-ae0d-4eb591348a87/download

University of Texas at Austin

Each category of additive manufacturing (AM) has specific fundamental limitations bounded by the physics and material properties involved. For example, the speed of fused filament fabrication (FFF) processes is bounded by how quickly thermoplastics can be melted, deposited, and resolidified while retaining material properties and dimensional accuracy. Incremental improvements approaching these theoretical limits will continue to occur, but more radical changes are necessary to completely overcome the current constraints. This paper considers some of the fundamental limits bounding FFF processes and investigates possible avenues for future research to overcome these limits. The framework for this analysis is the “Theory of Inventive Problem Solving” (TRIZ), a formalized problem solving and ideation tool that generalizes design-specific problems into contradicting engineering parameters, then suggests universal design principles based on analogy to solutions in other systems and patents. TRIZ has been used in many fields successfully, including the design of parts to be more manufacturable through AM, but literature on its application to additive manufacturing processes themselves is limited. Two case studies are shared demonstrating how TRIZ-based analysis can lead to radical improvements in FFF and other AM technologies.

null

['Subedi, Subodh C.', 'Thoma, Dan J.', 'Suresh, Krishnan']

2021-12-06T23:27:52Z

2021

Mechanical Engineering

null

['https://hdl.handle.net/2152/90716', 'http://dx.doi.org/10.26153/tsw/17635']

eng

2021 International Solid Freeform Fabrication Symposium

Open

['truss-type', 'support structures', 'selective laser melting', 'SLM']

Truss-Type Support Structures for SLM

Conference paper

https://repositories.lib.utexas.edu//bitstreams/0b5f4dc9-42e1-44a1-a3c2-2d23c62642f5/download

University of Texas at Austin

Support structures are critical in selective laser melting (SLM) of 3D metal additively manufactured components. Besides providing structural support, they serve as conduits for efficient heat dissipation. Support structures heavily influence the printability of a part as well as its physical and mechanical properties. Commonly used thin walled surface support structures are reliable, but are difficult to optimize, post-process, and often entrap a significant amount of powder. This paper presents the concept of truss-type surface support structures for SLM to address these challenges. The proposed structures are easy to optimize and provide better anchorage; further, they do not entrap powder, and are easy to remove. Experimental results demonstrate the effectiveness of these designs over commonly used support structures, paving a path towards optimal support structure design for SLM.

null

['Pegna, Joseph', 'Messia, David', 'Lee, Woo Ho']

2018-11-28T19:23:39Z

1997

Mechanical Engineering

doi:10.15781/T2348H24F

http://hdl.handle.net/2152/70325

eng

1997 International Solid Freeform Fabrication Symposium

Open

['Process Control, Rod growth', 'tessellation', '3-D LCVD']

Trussed Structures: FreeForm Fabrication without the Layers

Conference paper

https://repositories.lib.utexas.edu//bitstreams/7071b95a-baaa-4f3d-8089-d217dcce27b3/download

null

Recent progress in 3D-LCVD have demonstrated the advantages ofrod micro-fabrication, both from the point of view of the range of volumetric deposition rates -from 1cl- to 109 cubic micron per second- andfrom the point ofview ofprocessable materials. A methodforfabricating trussed structures by LCVD ofethylene was tested, based upon scanning of the laserfocus perpendicular to the laser axis during rod growth. Control of the process is achieved though feedback ofthe laser power. A closed loop system was designed, which maintains a constant volumetric deposition rate during growth. Such capability, combined with previous results by the authors and other researchers in the field, open a new approach to free form fabrication without layers. Indeed, current results constitute a proofofconceptfor the fabrication oftruss structures akin to a finite element mesh.

null

['Hiller, Jonathan', 'Lipson, Hod']

2020-03-10T16:41:13Z

9/10/08

Mechanical Engineering

null

['https://hdl.handle.net/2152/80228', 'http://dx.doi.org/10.26153/tsw/7247']

eng

2008 International Solid Freeform Fabrication Symposium

Open

Digital materials

Tunable Digital Material Properties of 3D Voxel Printers

Conference paper

https://repositories.lib.utexas.edu//bitstreams/76d4b6de-a233-469c-bc1c-e4447faa7bbf/download

null

Digital materials are composed of many discrete voxels placed in a massively parallel layer deposition process, as opposed to continuous (analog) deposition techniques. We explore the material properties attainable using a voxel-based freeform fabrication process and simulate how the properties can be tuned for a wide range of applications. By varying the precision, geometry, and material of the individual voxels, we obtain continuous control over the density, elastic modulus, CTE, ductility, and failure mode of the material. Also, we demonstrate the effects of several hierarchical voxel “microstructures”, resulting in interesting properties such as negative poisson’s ratio. This implies that digital materials can exhibit widely varying properties in a single desktop fabrication process.

null

['Teng, Chong', 'Pal, Deepankar', 'Gong, Haijun', 'Stucker, Brent']

2021-10-18T21:45:05Z

2014

Mechanical Engineering

null

https://hdl.handle.net/2152/89259

eng

2014 International Solid Freeform Fabrication Symposium

Open

['Metal Laser Sintering', 'thermal fields', 'thermo-mechanical properties', 'two dimensional structure']

A Two Dimensional Analytical Evaluation of Thermal Fields During Metal Laser Sintering Processes

Conference paper

https://repositories.lib.utexas.edu//bitstreams/a13dc913-4415-4525-b216-1a1b5ebbc140/download

University of Texas at Austin

Metal Laser Sintering (MLS) is a laser based manufacturing technique which is used for fabrication of parts in a layer-by-layer fashion using fine metal powders. Parts fabricated using MLS find wide applications in a myriad of areas such as medical, dental, and aerospace industries due to the availability of high geometric complexity, density, and their thermomechanical performance in service. A number of computational studies have been conducted in the past to help understand various underlying mechanisms related to laser melting and reconsolidation in order to arrive at strategies for better and faster machine architectures and process parameters combinations which result in stronger and longer-lasting parts. As intellectual property barriers fall, due to expiring patents and more competitors licensed to produce machines, the desire to produce better next-generation machines is increasing. In addition there is a parallel realization that the industry needs better ways to develop new materials and control schemes for MLS processing. In order to achieve these goals, in this study we will provide an insight into the various thermo-mechanical phenomena which occur during MLS by providing a brief update on computational studies in the literature followed by the derivation of an efficient fully analytical framework for this problem. A two dimensional example is provided illustrating various aspects of this formulation which will be modified for a full 3 Dimensional formulation and implementation in the future to achieve the above-mentioned goals.

null

['Sassaman, Doug', 'Hall, Peter', 'Fish, Scott', 'Beaman, Joseph']

2021-11-16T14:57:22Z

2018

Mechanical Engineering

null

['https://hdl.handle.net/2152/90303', 'http://dx.doi.org/10.26153/tsw/17224']

eng

2018 International Solid Freeform Fabrication Symposium

Open

['window contamination', 'contamination', 'nylon 11', 'selective laser sintering']

Two-Dimensional Characterization of Window Contamination in Selective Laser Sintering

Conference paper

https://repositories.lib.utexas.edu//bitstreams/8bddce91-2254-4082-88e5-f2c08684f58e/download

University of Texas at Austin

Most Laser Sintering machines suffer from an issue where it is hypothesized that hot gases produced during the laser sintering process collect on the Zinc selenide (ZnSe) window separating the build chamber from the environment. This contamination has previously been shown to reduce delivered laser power by up to 10%, and necessitate frequent cleaning and replacement of the windows. A power meter was constructed in order to perform ex-situ measurements of laser attenuation at various locations on the window. Identical builds were performed using fire-retardant nylon 11 on a DTM Sinterstation 2500, and the windows were measured before and after each build. Results indicate that contamination is not uniform on the window, and may cause a variation in laser attenuation up to 3.5%±0.25% depending on scanning location. It is also shown here that the contamination patterns are not repeatable from build to build, even if performed on the same machine.

null

['Chen, Tiebing', 'Zhang, Yuwen']

2019-11-20T16:15:52Z

2003

Mechanical Engineering

null

['https://hdl.handle.net/2152/78470', 'http://dx.doi.org/10.26153/tsw/5555']

eng

2003 International Solid Freeform Fabrication Symposium

Open

Two-Component Metal

Two-Dimensional Modeling of Sintering of a Two-Component Metal Powder Layer on Top of Multiple Sintered Layers with a Moving Gaussian Heat Source

Conference paper

https://repositories.lib.utexas.edu//bitstreams/93bc3964-4b80-4f32-8997-78e07a696fd4/download

null

Selective Laser Sintering (SLS) of metal powder is modeled as a two-dimensional melting and resolidification of a loose powder layer on top of the sintered metal layers with a moving heat source. The shrinkage induced by melting is accounted for and the problem is modeled using a temperature-transforming model. The results indicate that both the moving heat source intensity and scanning velocity have significant effects on the sintering process. Since the thermal conductivity of the sintered layer is relatively high compared with that of the loose powder, higher heat source intensity and lower scanning velocity are needed to achieve complete melting of the loose powder and bond the current layer to the existing sintered layers. A parametric study is performed and the best combinations of the processing parameters are recommended.

Support for this work by the Office of Naval Research under grant number N00014-02-1- 0356 is greatly acknowledged.

null

['Zhang, Jingwei', 'Li, Wei', 'Liou, Frank', 'Newkirk, Joseph']

2021-11-03T21:01:02Z

2017

Mechanical Engineering

null

https://hdl.handle.net/2152/89933

eng

2017 International Solid Freeform Fabrication Symposium

Open

['grain growth', 'fusion zone', 'cellular automata-finite element', 'direct metal deposition']

A Two-Dimensional Simulation of Grain Structure Growth Within Substrate and Fusion Zone During Direct Metal Deposition

Conference paper

https://repositories.lib.utexas.edu//bitstreams/5d9145eb-a5e9-41a8-a932-936e3aa86aa3/download

University of Texas at Austin

In this paper, a predictive model based on a cellular automaton (CA)-finite element (FE) method has been developed to simulate thermal history and microstructure evolution during metal solidification for a laser-based additive manufacturing process. The macroscopic FE calculation that is validated by thermocouple experiment is designed to update the temperature field and a high cooling rate. A cellular automata-finite element (CAFE) method is developed to describe grain growth in the fusion zone. In the mesoscopic CA model, heterogeneous nucleation sites, grain growth orientation and rate, epitaxial growth, remelting of preexisting grains, metal addition, grain competitive growth, and columnar to equiaxed phenomena were simulated. The developed “decentered polygon” growth algorithm is appropriate for the non-uniform temperature field. Finally, the single and multiple layer direct metal deposition (DMD) experiment is conducted to validate the characteristics of grain features in the simulation.

null

['Friel, R.J.', 'Harris, R.A.']

2021-10-05T19:26:17Z

2012

Mechanical Engineering

null

['https://hdl.handle.net/2152/88417', 'http://dx.doi.org/10.26153/tsw/15356']

eng

2012 International Solid Freeform Fabrication Symposium

Open

['Ultrasonic Additive Manufacturing', 'Loughborough University', 'interlaminar bonding', 'fibre positioning', 'electrical circuitry']

Ultrasonic Additive Manufacturing Research at Loughborough University

Conference paper

https://repositories.lib.utexas.edu//bitstreams/bdfbff3c-8058-4c9e-87f3-1f734e3d591c/download

University of Texas at Austin

Ultrasonic Additive Manufacturing (UAM) has been subject to research and investigation at Loughborough University since 2001. In recent years, three particular areas of significant focus have been: • The influence of pre-process material texture on interlaminar bonding. • Secure fibre positioning through laser machined channels. • Freeform electrical circuitry integration. This paper details the key findings and a number of conclusions from these work areas. The results of this work have led to the further research and developmental applications for the UAM technology.

null

['Billah, Kazi Md Masum', 'Coronel, Jose L. Jr.', 'Chacon, Sarah', 'Wicker, Ryan B.', 'Espalin, David']

2021-11-16T16:42:15Z

2019

Mechanical Engineering

null

['https://hdl.handle.net/2152/90341', 'http://dx.doi.org/10.26153/tsw/17262']

eng

2019 International Solid Freeform Fabrication Symposium

Open

['ultrasonic embedding', 'carbon fiber', 'polycarbonate', 'thermoplastics', '3D printing']

Ultrasonic Embedding of Continuous Carbon Fiber into 3D printed Thermoplastic Parts

Conference paper

https://repositories.lib.utexas.edu//bitstreams/fa53ed07-3902-452b-afc4-142435aceab2/download

University of Texas at Austin

A novel multimaterial fabrication process was developed to embed continuous bundles of carbon fiber (CF) into polycarbonate (PC) substrates using ultrasonic energy. Continuous CF possesses superior reinforcement properties compared to that of chopped or short fibers. In this research, dry continuous CF bundles were impregnated with a PC solution prior to embedding. Three printing raster orientations were studied (0°, 45°, and 90°), where three layers of CCF were embedded within each test specimen. Characterizations including tensile, flexural, and dynamic mechanical analysis were carried out to investigate reinforcement related properties. Results showed an increase in ultimate tensile strength between neat PC (37 MPa) and CF reinforced specimens (141 MPa). An automated ultrasonic embedding process allowed for the selective deposition of CF, regardless of the raster orientation. Future development of continuous CF reinforced parts could enable smart part fabrication, with applications in structural health monitoring, microwave shielding, and thermal management.

null

['Halloran, John W.', 'Griffith, Michelle L.']

2018-10-03T18:38:29Z

1994

Mechanical Engineering

doi:10.15781/T2599ZM4Q

http://hdl.handle.net/2152/68676

eng

1994 International Solid Freeform Fabrication Symposium

Open

['ceramic green bodies', 'alumina', 'stereolithography']

Ultraviolet Curing of Highly Loaded Ceramic Suspensions for Stereolithography of Ceramics

Conference paper

https://repositories.lib.utexas.edu//bitstreams/eff34e04-c6dc-42e7-b119-ed38258610cc/download

null

Ceramic green bodies can be created using stereolithography methods where a ceramic slip consisting of 45-55 vlo ceramic powder is dispersed within an ultraviolet-curable aqueous acrylamide solution. Two ceramic materials were investigated: silica [Si02] for investment casting purposes, and alumina [AI203] for structural parts. After mixing the powders in the curable solution, the ceramic slip is tape cast onto a substrate for cure under a high intensity ultraviolet lamp (220-450 nm) at different exposure times. The materials systems were evaluated at different solids loadings (10-50 v/o) for cure thickness and viscosity control. Silica had a cure depth of 330 f.lm at a solids loading of 55 vlo, and at 50 vlo, alumina had a cure depth of 300 f.lm. Preliminary work utilizing scattering theory revealed the cure depth is controlled by the particle size and the refractive index difference between the ceramic and ultraviolet solution. The refractive index difference is the dominating factor. Two particle size distributions of alumina were used to more accurately determine the effect of particle size.

null

['Francis, Jomy', 'Sparks, Todd E.', 'Liou, Frank']

2021-09-29T22:25:36Z

2010

Mechanical Engineering

null

['https://hdl.handle.net/2152/88220', 'http://dx.doi.org/10.26153/tsw/15161']

eng

2010 International Solid Freeform Fabrication Symposium

Open

['Laser Aided Manufacturing Process', 'laser deposition', 'scallop heights', 'surface finish manufacturing']

Uncertainty Analysis in Laser Deposition Finish Machining Operations

Conference paper

https://repositories.lib.utexas.edu//bitstreams/d71dc882-1693-46c1-9de6-cc300f9d3021/download

University of Texas at Austin

The Laser Aided Manufacturing Process (LAMP) from Missouri S&T is a laser based metals rapid manufacturing process that uses machining to improve the final part's surface finish. When free-form machining, the absence of enough deposited material results in inconsistent scallop heights which result in poor surface finish or incorrect geometry in the final part. This paper investigates a probabilistic approach to various uncertainties involved in the deposition and subsequent machining of an arbitrary part. Furthermore, this paper analyses the machine errors which makes the response of Scallop Height to exceed the predefined maximum scallop height when traveling along the tool path interval distance. Tackling these problems allows us to achieve the final part shape with higher accuracy.

null

Yasa, Evren

2021-11-10T22:54:33Z

2018

Mechanical Engineering

null

['https://hdl.handle.net/2152/90200', 'http://dx.doi.org/10.26153/tsw/17121']

eng

2018 International Solid Freeform Fabrication Symposium

Open

['metallic material', 'selective laser melting', 'additive manufacturing', 'industrial application', 'research & development']

Understanding Adopting Selective Laser Melting of Metallic Materials

Conference paper

https://repositories.lib.utexas.edu//bitstreams/6179f683-28be-4821-97d1-1c6012779813/download

University of Texas at Austin

Additive manufacturing, considered as the future of manufacturing or the new industrial revolution, presents many advantages over conventional manufacturing. These include manufacturing integrated parts, eliminating joining processes, shortening lead times from design to testing, lightweight structures, being able to produce very complex geometries at almost no added cost, etc. Therefore, many industrial sectors such as aerospace, defense, biomedical and automotive, are getting more excited about adopting these technologies into their production lines. However, the shortage of experienced personnel in the field of Additive Manufacturing may make the transition period difficult and troublesome. Since AM technologies are rather new and immature compared to conventional manufacturing, many issues in terms of safety, environment, materials, process development, design guidelines as well as testing and validation arise. This paper will address and review lessons learned as a result of implementing selective laser melting for industrial applications as well as for research and development purposes so that this valuable outcome can be used as a guideline by beginners in this field.

null

['Khoshkhoo, Ali', 'Carrano, Andres L.', 'Blersch, David M.', 'Ghaednia, Hamid', 'Kardel, Kamran']

2021-11-04T20:56:51Z

2017

Mechanical Engineering

null

['https://hdl.handle.net/2152/90026', 'http://dx.doi.org/10.26153/16947']

eng

2017 International Solid Freeform Fabrication Symposium

Open

['additive manufacturing', 'reverse engineering', 'surface metrology', 'topograhy', 'natural surfaces', 'benthic algae']

Understanding and Engineering of Natural Surfaces with Additive Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/f741148f-7efc-47b1-9e58-ee2b9060c6e0/download

University of Texas at Austin

Benthic algae systems that attach to substrata have been shown effective in water pollution remediation and biomass production, but yields are limited by attachment preferences in wild cultivars. This work seeks to uncover the surface topography preferences for algal attachment by reproducing natural surface topographies using additive manufacturing. To date, no other research efforts have taken advantage of using additive manufacturing to reverse engineer the characteristics of natural surfaces for enhancement of the attachment preferences of certain periphyton species towards substrata topography. Natural rocks and surfaces with attached biofilms were retrieved from streams, scanned with optical profilometry, and the surface characteristics were analyzed. A material jetting process is used to additively manufacture the surfaces, followed by optical profilometry to validate the resultant topography. The results show that certain texture parameters (e.g., Smr, Sa, and Sv) are significant in affecting the biomass adhesion of specific algal communities.

null

['Wörz, A.', 'Drummer, D.']

2021-11-11T16:06:05Z

2018

Mechanical Engineering

null

['https://hdl.handle.net/2152/90229', 'http://dx.doi.org/10.26153/tsw/17150']

eng

2018 International Solid Freeform Fabrication Symposium

Open

['selective laser sintering', 'hatching', 'mechanical behavior', 'polyamide 12']

Understanding Hatch-Dependent Part Properties in SLS

Conference paper

https://repositories.lib.utexas.edu//bitstreams/3b754921-c6d8-4636-8e37-111cae5ff217/download

University of Texas at Austin

Selective laser sintering of polymers (SLS) is on the verge from pure prototyping to producing individualized complex parts for series application. As the parts are generated layer-wise and the influence of process-parameters as well as part orientations are well-known, the aim of the paper is to point out the influence of the layer-wise manufacturing in dependence of the hatching strategy on the resulting part properties as these are constant process-steps. Therefore, tensile bars with different number of layers but constant layer-thickness were produced using different hatching strategies and investigated depending density, surface roughness and mechanical properties. The results showed a strong increase of the mechanical properties, ductile breaking behavior and part density as well as decreasing surface roughness with higher layer numbers as well as the hatching strategies. Therefore, the results point out significant interaction between constant process steps and resulting part properties.

null

['Lavin, J.M.', 'Keicher, D.M.', 'Whetten, S.R.', 'Moore, P.B.', 'Mani, S.S.']

2021-10-27T21:47:32Z

2016

Mechanical Engineering

null

https://hdl.handle.net/2152/89626

eng

2016 International Solid Freeform Fabrication Symposium

Open

['defects', 'polyimide films', 'aerosol based printing']

Understanding Sources of Defects in Polyimide Films Using Aerosol Based Printing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/7bd3d21f-40a0-4c4d-baa1-c73641bc8d77/download

University of Texas at Austin

A study of the sources of defects in films of commercially available polyamic acid fabricated using aerosol based printing was carried out. Printing was conducted using a Sono-Tek spray nozzle on multi-modular Direct Write Additive Manufacturing System. The driving force behind this work stemmed from the need to form smooth, defect free films to be used in electronic components. While numerous process conditions give rise to defects such as the obvious substrate cleanliness, efforts here focused on the more subtle conditions such as deposition temperature, deposition speed, nozzle height from the substrate and cure temperature. The results of this study led to the identification of the most critical source of defects and to a set of optimal process conditions in the printing of polyimide films using aerosol based printing.

null

['Mao, Qing', 'Coutris, Nicole', 'Gibert, James', 'Fadel, Georges']

2021-10-19T17:55:59Z

2015

Mechanical Engineering

null

https://hdl.handle.net/2152/89310

eng

2014 International Solid Freeform Fabrication Symposium

Open

['Ultrasonic Additive Manufacturing', 'plasticity', 'heat transfer', 'friction', 'lump parameter models']

Understanding the Dynamics of Ultrasonic Additive Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/fa396778-2b63-4a82-844e-abe00be0c0fb/download

University of Texas at Austin

Ultrasonic Additive Manufacturing (UAM) is an additive manufacturing technique that uses ultrasound to merge metal foils (150 µm thick, 24 mm wide) layer by layer to fabricate three-dimensional bodies. As new layers are deposited and the height-to-width ratio of the built feature changes, the dynamics of UAM changes accordingly. Prior research suggested the existence of a limit for the height-to-width ratio. Above this limit, additional layers fail to bond because the built feature reaches its resonance frequency. Specifically, the bond failure is affected by the lack of plastic shear deformation between two foils which is essential to the generation of true metallic bonds. As the height-to-width ratio falls in the critical range, the built feature becomes resonant under the high-frequency excitations (20 kHz) of the sonotrode, leading to large-amplitude oscillations matching those of the sonotrode, and resulting in reduction of differential motion and therefore plastic shear deformation between the foils. In order to develop a model incorporating plasticity, heat transfer, and friction to study UAM, 2-D and 3-D lump parameter models consisting of mass-spring networks are proposed to study the dynamics of the elastic part of the built feature. The models are established such that they preserve the modal parameters of the built feature in free vibration. The lumped parameter models are validated by comparing their modal predictions with those from 2-D and 3-D finite element models. The lumped parameter model will be coupled with a 3-D finite element model to describe an elasto-plastic bonding layer introducing the friction and thermal aspects of UAM. By examining the deformation of the bonding layer under the combined effects of the excitation of the sonotrode and the vibration of the built feature, the bond failure due to geometry change of the built feature will be better understood and quantified in the future.

null

['Wörz, A.', 'Wudy, K.', 'Drummer, D.']

2021-11-18T01:46:36Z

2019

Mechanical Engineering

null

['https://hdl.handle.net/2152/90399', 'http://dx.doi.org/10.26153/tsw/17320']

eng

2019 International Solid Freeform Fabrication Symposium

Open

['tensile bars', 'layer amounts', 'energy densities', 'mechanical properties', 'roughness', 'density', 'particle melt', 'PA12', 'selective laser sintering']

Understanding the Influence of Energy-Density of the Layer Dependent Part Properties in Laser-Sintering of PA12

Conference paper

https://repositories.lib.utexas.edu//bitstreams/1dc73f27-b423-435d-b450-d83eefb03ab1/download

University of Texas at Austin

As the demand for individualization and complex parts is continuously growing, laser-sintering of polymers is on the edge from a pure prototyping technology to manufacturing parts for applications in series production. The influences on resulting parts and layer depending part properties are well known in the literature but the understanding of the interaction between process parameters and layer dependent properties is missing and limiting the dimensioning. Within this study, tensile bars with different amounts of layers and energy densities were produced and investigated for the resulting mechanical properties, roughness, density and the degree of particle melt. The results showed a strong interaction between the energy density and amount of layers, which results in differences in the fracture behavior as well as the mechanical properties. Therefore, the presented results enable the prediction of necessary part thickness for dimensioning thin parts with laser-sintering.

null

['Pavan, Michele', 'Craeghs, Tom', 'Kruth, Jean-Pierre', 'Dewulf, Wim']

2021-10-28T15:13:42Z

2016

Mechanical Engineering

null

https://hdl.handle.net/2152/89660

eng

2016 International Solid Freeform Fabrication Symposium

Open

['x-rary computed tomography', 'laser sintering', 'porosity', 'microscale level']

Understanding the Laser Sintering of Polymers at Microscale Level by Using X-Ray Computed Tomography

Conference paper

https://repositories.lib.utexas.edu//bitstreams/c264394d-42e7-47d4-ae39-a343d3925fcd/download

University of Texas at Austin

Literature reports on many cases where X-ray Computed Tomography (CT) has been used to measure the porosity of laser sintered (LS) polymeric parts, in order to characterize the process parameters’ influence on their density. However, this approach implies to perform a CT scan for each parameter set being assessed, making the evaluation very costly and time consuming. Moreover, this approach does not provide useful information about the coalescence steps of the process and the local variation of the powder packing density which happen at the microscale level, namely at dimensions comparable to the layer thickness used during the process. This work presents a new CT-based approach which allows to assess at the microscale the variation of the sintering conditions for several scanning strategies at the same time. The study focuses on PA12 powder, but the proposed approach is general and can potentially be applied to every laser sinterable polymeric powder.

null

['Gockel, Joy', 'Beuth, Jack']

2021-10-11T21:57:33Z

2013

Mechanical Engineering

null

['https://hdl.handle.net/2152/88657', 'http://dx.doi.org/10.26153/tsw/15591']

eng

2013 International Solid Freeform Fabrication Symposium

Open

['direct metal additive manufacturing', 'additive manufacturing', 'process mapping', 'metal deposition', 'Ti-6Al-4V', 'melt pool geometry', 'microstructure']

Understanding Ti-6Al-4V Microstructure Control in Additive Manufacturing via Process Maps

Conference paper

https://repositories.lib.utexas.edu//bitstreams/e3c9fff6-8405-49eb-bbee-cd14f7cb9ff4/download

University of Texas at Austin

In direct metal additive manufacturing, the ability to predict and control as-deposited microstructure can reduce the need for post-processing and speed up the qualification process. In this work, a microstructure process map is presented for deposition of single beads of Ti-6Al4V using an electron beam wire feed process. Further, comparison with a previously developed process map for melt pool geometry control demonstrates that indirect control of Ti-6Al-4V solidification microstructure (prior beta grain size and morphology) is possible through direct, real time melt pool dimension control. These approaches for microstructure prediction and control can be extended to additional additive processes such as electron beam powder bed processes.

null

['Muhammad, Muztahid', 'Soman, Sajith', 'Ahmad, Nabeel', 'Wells, Douglas N.', 'Shao, Shuai', 'Shamsaei, Nima']

2024-03-26T16:51:38Z

2023

Mechanical Engineering

null

['https://hdl.handle.net/2152/124370', 'https://doi.org/10.26153/tsw/50978']

en_US

2023 International Solid Freeform Fabrication Symposium

Open

['laser powder bed fusion', 'Inconel 718', 'facet', 'NASGRO', 'fatigue life prediction']

UNIAXIAL FATIGUE BEHAVIOR AND LIFE PREDICTION OF ADDITIVELY MANUFACTURED INCONEL 718 WITH DIFFERENT GRAIN MORPHOLOGY

Conference paper

https://repositories.lib.utexas.edu//bitstreams/957620d6-c100-4d43-9a2c-61098268a8c7/download

University of Texas at Austin

Understanding the fatigue behavior and failure mechanisms is essential for qualifying and standardizing additively manufactured metallic components. This study investigates the uniaxial fatigue behavior and failure mechanisms of laser powder bed fused (L-PBF) Inconel 718 (IN718) specimens with different grain sizes obtained by altering the process parameters and heat treatment. Uniaxial, fully-reversed strain-controlled fatigue tests were conducted on specimens with machined and polished surface conditions. Microstructural analysis and fractography using a scanning electron microscope were performed to measure the sizes of grains and facets. Fatigue cracks were initiated at the persistent slip bands near or at the surfaces rather than process-induced volumetric defects in all cases. The fatigue behavior of L-PBF IN718 specimens was correlated with the sizes of grains and facets. Fatigue life estimation incorporating the NASGRO equation and √𝑎𝑟𝑒𝑎 of the grain sizes was performed and shown to predict fatigue life within scatter bands of five.

null

['Aguilera, E.', 'Bailey, C.', 'Espalin, D.', 'MacDonald, E.', 'Wicker, R.']

2021-10-26T18:07:47Z

2016

Mechanical Engineering

null

https://hdl.handle.net/2152/89545

eng

2016 International Solid Freeform Fabrication Symposium

Open

['additive manufacturing', '3D printing', 'electronics', 'automation', 'software']

Unified Software for Multi-Functional G-Code: A Method for Implementing Multi-Technology Additive Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/c023c093-d16c-4eac-9d45-fb1ca8ed18bb/download

University of Texas at Austin

Additive manufacturing (AM) began a manufacturing revolution moving industrial production into consumer homes. With interest shifting toward multi-functional parts fabricated through AM technologies, multi-functional fabrication systems are now being developed. Merging different manufacturing technologies into a single machine is a challenge, but ongoing research in the development of multi-technology systems has shown promise. The software and automation aspects of multi-technology systems are being developed in unison. This paper explores the challenges and approaches to developing software that interfaces with multifunctional CADs and creates files for direct use in multi-technology AM machines.

null

['Andersen, S.A.', 'Meinert, K.Æ.', 'Kjer, M.B.', 'Nadimpalli, V.K.', 'Pedersen, D.B.']

2023-04-03T15:56:25Z

2022

Mechanical Engineering

null

['https://hdl.handle.net/2152/117721', 'http://dx.doi.org/10.26153/tsw/44600']

eng

2022 International Solid Freeform Fabrication Symposium

Open

powder bed fusion

A Unified System Controller for Open-Source Powder Bed Fusion Systems

Conference paper

https://repositories.lib.utexas.edu//bitstreams/30a0ba89-d515-45c1-8fc4-a02607ebaf13/download

null

This paper presents an open-architecture systems controller for laser powder-bed fusion (LPBF). The controller gives the operator direct low-level hardware control, and thereby bridges the gap, between system and researcher, often invoked by the proprietary nature of commercial LPBF systems. As part of the open-source framework, the bespoke controller provides an open and customizable way of controlling the governing subsystems, e.g., scanner (XY2-100), laser, gas flow, and motorized actuation. Furthermore, the unified system controller was designed to retrieve feedback from the scanner and designated process sensors. Utilizing the process feedback the uni- fied system controller demonstrates its capabilities to support both open and closed-loop control routines. The embedded firmware and custom circuitry allow the unified systems controller to serve as a versatile controller for PBF systems, and a powerful tool when investigating and coupling process effects to system behavior.

null

['Cook, D.', 'Newbauer, S.', 'Leslie, A.', 'Gervasi, V.', 'Kumpaty, S.']

2021-10-05T15:55:20Z

2012

Mechanical Engineering

null

['https://hdl.handle.net/2152/88399', 'http://dx.doi.org/10.26153/tsw/15338']

eng

2012 International Solid Freeform Fabrication Symposium

Open

['additive manufacturing', 'thermal conductivity', 'ankle-foot orthosis', 'wearable medical devices', 'unit cells']

Unit-Cell-Based Custom Thermal Management through Additive Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/2071ff15-94cc-4401-9179-32176d0566c7/download

University of Texas at Austin

Using previously-defined effective thermal conductivities for structural unit cells, a custom thermal-management structure has been developed for a powered ankle-foot orthosis. The structure provides the requisite personal safety for wearable medical devices. Minimal mass was achieved through the employment of these unit cells. Fabrication of the resultant structure is made practical by additive manufacturing. Results of the virtual testing are reported, as well as the preliminary results of an energy-based comparative-performance analysis of natural versus forced convection. Future work includes the integration of phase-change materials and thermoelectric generators.

null

['Tang, Yunlong', 'Xiong, Yi', 'Park, Sang-in', 'Rosen, David W.']

2021-11-18T16:59:16Z

2019

Mechanical Engineering

null

['https://hdl.handle.net/2152/90428', 'http://dx.doi.org/10.26153/tsw/17349']

eng

2019 International Solid Freeform Fabrication Symposium

Open

['material template', 'multiscale design', 'multiscale modeling', 'additive manufacturing']

A Universal Material Template for Multiscale Design and Modeling of Additive Manufacturing Processes

Conference paper

https://repositories.lib.utexas.edu//bitstreams/de06ec77-4f8f-49c3-824e-0b8533d79202/download

University of Texas at Austin

In this paper, a universal material template is developed to digitally describe the materials with spatially distributed compositions and microstructures for multiscale design and modeling of additive manufacturing processes. The developed template is organized in the form of a multi-level hierarchical structure. The root node of a material template contains four sub-nodes. They are “descriptors list”, “constituent materials”, “position information” and “primitive information”. The format of each sub-node has been given in this paper to help users to establish a standardized description of microstructures of materials. To validate the effectiveness of the proposed template, the microstructures of two different types of commonly used materials in additive manufacturing processes are reconstructed from the pre-defined material templates. The results show the developed material template can accurately and precisely control the microstructures of materials. Based on the developed material template, the multiscale heterogeneous modeling method can be developed in the future.

null

['Lang, Andrew', 'Ortiz Rios, Cesar', 'Newkirk, Joseph', 'Landers, Robert G.', 'Castle, James', 'Bristow, Douglas A.']

2021-12-01T22:35:54Z

2021

Mechanical Engineering

null

['https://hdl.handle.net/2152/90641', 'http://dx.doi.org/10.26153/tsw/17560']

eng

2021 International Solid Freeform Fabrication Symposium

Open

['defects', '2D SEM', 'XCT', 'X-ray CT', 'laser powder bed fusion']

Unsupervised Defect Classification of 2D SEM and 3D X-Ray CT Images from Laser Powder Bed Fusion

Conference paper

https://repositories.lib.utexas.edu//bitstreams/e0f1f79d-52b1-4979-9128-e627e4c95a96/download

University of Texas at Austin

This work discusses a method to classify defects in laser powder bed fusion using 2D images of layer samples taken by Scanning Electron Microscope (SEM) and 3D image stacks of a full part by X-Ray Computed Tomography (XCT). Images using SEM are taken of a sampled layer in a printed part and unsupervised classification of defects in the SEM images is performed with Otsu’s thresholding method, K-means classification, and the Robust Automatic Threshold Selection algorithm. The performance of the classifiers, measured against human-generated ground truth defect labels, is improved by registering and fusing multiple SEM images taken under different settings and detector locations. Otsu’s method is shown to be the best classifier for the 3D XCT dataset. Finally, the 2D sample is located in the 3D XCT array and the reliability of the 3D defect classification technique is validated.

null

['Ziegler, S.', 'Schleifenbaum, J.H.']

2024-03-27T03:22:37Z

2023

Mechanical Engineering

null

['https://hdl.handle.net/2152/124463', 'https://doi.org/10.26153/tsw/51071']

en_US

2023 International Solid Freeform Fabrication Symposium

Open

['additive manufacturing', 'trend analysis', 'market intelligence', 'text mining']

Usage of Unconventional Data Sources for Market Intelligence (MI) in the Field of Additive Manufacturing (AM) - Expert Networks, Technology Territories and Trends

Conference paper

https://repositories.lib.utexas.edu//bitstreams/9b12bad9-d4e6-425d-8fca-2be6d1cc7f32/download

University of Texas at Austin

The geographic expansion of the markets for AM increasingly confronts companies with greater competitiveness due to the globalization. In addition, market participants are facing rapid changes in the business environment - due to new information and communication technologies. Companies only have a chance to hold their market position if they quickly adopt market changes. Therefore, the decision-making process needs to be accelerated by on-demand information provision. MI offers one possibility to meet these requirements, but typically based on external unstructured data for market and competitive evaluation, which makes it cost and time consuming. A specific investigation of such data sources related to MI for systematic use within the AM markets is being carried out. For this purpose, different data sources (e.g. LinkedIn) will be identified, analysed with focus on information synthesis using text mining and their suitability for the evaluation of expert networks, technology territories and trends be presented.

null

['Wang, Jenny', 'Jariwala, Amit', 'Rosen, David']

2023-01-27T17:39:57Z

2022

Mechanical Engineering

null

['https://hdl.handle.net/2152/117342', 'http://dx.doi.org/10.26153/tsw/44223']

eng

2022 International Solid Freeform Fabrication Symposium

Open

stereolithography

Use of a Fluid Interface to Reduce Support Structures in Top-Down Stereolithography

Conference paper

https://repositories.lib.utexas.edu//bitstreams/e995aa91-7b19-41cb-b217-c2a5a3653b21/download

null

Stereolithography (SLA) is a vat photopolymerization additive manufacturing process which utilizes ultraviolet (UV) light energy to cure resin layer-by-layer to build parts. The fabrication of overhanging geometry in SLA typically requires sacrificial support structures. Printing supports increases fabrication time and material usage, and their removal prolongs the post-processing and has a detrimental effect on the surface quality of the final part. This study investigates a top-down mask projection SLA system in which a fluid of similar density to the cured resin is used to support the part during fabrication. The buoyant force of the displaced fluid counteracts the gravitational force the part experiences, thus reducing the need for support structures in overhangs. The overall system design is presented, and a first-order analytical model of part deformation resulting from internal stresses and buoyant and gravitational forces is proposed.

null

['Hantke, N.', 'Grimm, T.', 'Sehrt, J.T.']

2024-03-26T22:58:12Z

2023

Mechanical Engineering

null

['https://hdl.handle.net/2152/124437', 'https://doi.org/10.26153/tsw/51045']

en_US

2023 International Solid Freeform Fabrication Symposium

Open

['powder-bed fusion', 'laser beam', 'vibration', 'metal', 'additive manufacturing']

USE OF A VIBRATING BUILD PLATFORM DURING POWDER-BED FUSION OF METALS USING A LASER BEAM

Conference paper

https://repositories.lib.utexas.edu//bitstreams/d050ab25-f8e5-47bf-8f97-7888a4928b34/download

University of Texas at Austin

Powder-bed fusion of metals using a laser beam (PBF-LB/M) is an additive manufacturing technique with rising interest in industry and academia. One major topic of current research is to optimize the performance of parts manufactured by PBF-LB/M. The use of vibrations during the solidification of metals to improve their mechanical properties is well-known for metal casting and directed energy deposition. In this work, a vibrating build platform was used during the PBF-LB/M process to influence the microstructure of parts. Analyses show an increase in sample hardness by up to 12.3 % for the same process parameters. Especially for process parameters that produce parts with lower relative densities, vibrations have an influence on part density. With an increase in part density, this effect gets less pronounced.

null

['Fox, Luke', 'Ellis, Adam', 'Hopkinson, Neil']

2021-10-19T21:30:49Z

2015

Mechanical Engineering

null

https://hdl.handle.net/2152/89342

eng

2015 International Solid Freeform Fabrication Symposium

Open

['high speed sintering', 'ink', 'supply chain']

Use of an Alternative Ink in the High Speed Sintering Process

Conference paper

https://repositories.lib.utexas.edu//bitstreams/e20a708b-f39e-4a94-8605-566d631fc91d/download

University of Texas at Austin

High Speed Sintering is a polymer Additive Manufacturing process, which builds parts by the use of inkjet printing and infrared lamp technology, as opposed to lasers and optics used in Laser Sintering. For High Speed Sintering to be a viable method to build fast moving consumer goods the ability to use different inks is critical. This research investigated the effects of using two separate inks in the High Speed Sintering process. This work shows it is possible to use inks from different suppliers, which opens up a wider supply chain.

null

['Yang, Li', "O'Neil, Chris", 'Wu, Yan']

2021-11-08T21:34:18Z

2017

Mechanical Engineering

null

['https://hdl.handle.net/2152/90047', 'http://dx.doi.org/10.26153/tsw/16968']

eng

2017 International Solid Freeform Fabrication Symposium

Open

['electropolishing', 'surface treatment', 'powder bed fusion', 'superalloy', 'IN718', 'additive manufacturing']

The Use of Electropolishing Surface Treatment on IN718 Parts Fabricated by Laser Powder Bed Fusion Process

Conference paper

https://repositories.lib.utexas.edu//bitstreams/3f7cf3f9-853a-4f95-ad99-5358ad9c8ffc/download

University of Texas at Austin

In various applications of additively manufactured Ni-based superalloys, high surface finish quality is required. In this work, electropolishing surface treatment with anhydrous electrolyte solution was employed to improve the surface quality of the IN718 parts fabricated by laser powder bed fusion process. Various process parameters including electropolishing voltage, temperature, electrolyte spacing and electrolyte flow speed were investigated for their effect on the improvement of surface roughness characteristics. In addition, the effect of electrolyte flow uniformity on the surface quality deviation was investigated. The results provided additional insights to the recently proposed polishing methods proposed by the same group, which clearly indicates the potential benefit of introducing highly regulated electrolyte flow in the polishing of AM metal parts.

null

['Purser, Molly', 'Cansizoglu, Omer', 'Haslauer, Carla', 'Harrysson, Ola L. A.', 'Loboa, Elizabeth']

2020-03-10T15:26:28Z

9/4/07

Mechanical Engineering

null

['https://hdl.handle.net/2152/80216', 'http://dx.doi.org/10.26153/tsw/7235']

eng

2007 International Solid Freeform Fabrication Symposium

Open

polycaprolactone

The Use of Layered Freeform Fabrication Technologies to Produce Tissue Engineering Scaffolds for Skull Patches

Conference paper

https://repositories.lib.utexas.edu//bitstreams/10381f3e-2e2b-486e-afb5-7e5d9d1af20d/download

null

Congenital skull defects in infants are difficult to correct using metal plates due to the growth of the skull. Tissue engineering of bone patches could be the answer to help such patients. Custom scaffolds have been designed based on Computed Tomography (CT) images of the patient’s skull. An in-house developed single screw extruder, casting and a commercial laser cutter has been evaluated in the fabrication of pure polycaprolactone (PCL) scaffolds as well as PCL mixed with hydroxyapatite (HA) scaffolds. Evaluation criteria for each process included the ability to maintain an optimal pore size for cells to proliferate, inclusion of micro surface properties for cell adhesion, incorporation of hydroxyapatite, and ability to maintain desired shape. The mechanical properties of the fabricated scaffolds will be presented in this paper as well as initial cell seeding results with human adipose-derived adult stem (hADAS) cells.

null

['Sager, Benay', 'Rosen, David W.']

2020-02-21T20:35:31Z

8/3/05

Mechanical Engineering

null

['https://hdl.handle.net/2152/80070', 'http://dx.doi.org/10.26153/tsw/7091']

eng

2005 International Solid Freeform Fabrication Symposium

Open

Stereolithography

Use of Parameter Estimation for Stereolithography Surface Finish Improvement

Conference paper

https://repositories.lib.utexas.edu//bitstreams/dba92737-bada-4fd2-b95e-4de23e7007cc/download

null

In order to improve Stereolithography (SLA) surface finish, a systematic approach based on estimation of process parameters is needed. In this paper, the exposure on a desired SLA build surface is formulated as a function of process parameters. The deviation of exposure on this surface from the critical exposure, which is the threshold that determines curing in the SLA process, is formulated using least squares minimization. By applying inverse design techniques, SLA process parameters that satisfy this least squares minimization are determined. Application of parameter estimation formulation to important SLA geometries is presented and the results, including surface finish improvement, are discussed.

null

['Rybalcenko, Konstantin', 'Gaio, André', 'Folgar, Luis', 'Crabtree, Joseph']

2021-11-30T20:40:27Z

2019

Mechanical Engineering

null

['https://hdl.handle.net/2152/90539', 'http://dx.doi.org/10.26153/tsw/17458']

eng

2019 International Solid Freeform Fabrication Symposium

Open

['additive manufacturing', 'measuring instrument', 'part surfaces', 'automation', 'in-process optics']

The Use of Smart In-Process Optical Measuring Instrument for the Automation of Additive Manufacturing Processes

Conference paper

https://repositories.lib.utexas.edu//bitstreams/50a21580-c718-4bea-bfb1-a98eb659fe22/download

University of Texas at Austin

null

This paper presents a novel measuring instrument for part surfaces with millimetre- to micrometre-sized features.

null

['Rybalcenko, Konstantin', 'Gaio, André', 'Folgar, Luis', 'Crabtree, Joseph']

2021-11-18T17:54:27Z

2019

Mechanical Engineering

null

['https://hdl.handle.net/2152/90447', 'http://dx.doi.org/10.26153/tsw/17368']

eng

2019 International Solid Freeform Fabrication Symposium

Open

['in-process optical measuring', 'measuring instrument', 'automation', 'additive manufacturing']

The Use of Smart In-Process Optical Measuring Instrument for the Automation of Additive Manufacturing Processes

Conference paper

https://repositories.lib.utexas.edu//bitstreams/8523b474-2ecd-4ba4-8297-1e15da2c796d/download

University of Texas at Austin

null

This paper presents a novel measuring instrument for part surfaces with millimetre- to micrometre-sized features.

null

['Gilman, Charles R.', 'Rock, Stephen J.']

2018-11-02T14:00:36Z

1995

Mechanical Engineering

doi:10.15781/T2T72817T

http://hdl.handle.net/2152/69328

eng

1995 International Solid Freeform Fabrication Symposium

Open

['SFF', 'CAD', 'STL']

The Use of STEP to Integrate Design and Solid Freeform Fabrication

Conference paper

https://repositories.lib.utexas.edu//bitstreams/070a7797-828f-44bb-ae6e-82656fe7d415/download

null

The Standard for the Exchange of Product Model Data (STEP), ISO 10303, is a developing International Standard for the exchange of product information between many different engineering and manufacturing applications. This paper describes an architecture and methodology, using STEP, that integrates a heterogeneous environment of CAD and Solid Freeform Fabrication (SFF) systems. The prototype software discussed in this paper demonstrates the use of STEP to provide CAD product data to a SFF system. The architecture described in this paper also addresses the role of the STEP standards in an environment where STL and other SFF part data formats must also be supported.

null

['Lough, Cody S.', 'Wang, Xin', 'Smith, Christopher C.', 'Adeniji, Olaseni', 'Landers, Robert G.', 'Bristow, Douglas A.', 'Kinzel, Edward C.']

2021-11-15T22:31:24Z

2018

Mechanical Engineering

null

['https://hdl.handle.net/2152/90296', 'http://dx.doi.org/10.26153/tsw/17217']

eng

2018 International Solid Freeform Fabrication Symposium

Open

['SWIR imaging', 'monitoring', 'part quality', 'defect location', 'defects', '304L', 'stainless steel', 'selective laser melting']

Use of SWIR Imaging to Monitor Layer-to-Layer Part Quality During SLM of 304L Stainless Steel

Conference paper

https://repositories.lib.utexas.edu//bitstreams/2d8a149d-ee4f-4221-a91c-0c87a3424337/download

University of Texas at Austin

This paper evaluates using in-situ SWIR imaging to monitor part quality and identify potential defect locations introduced during Selective Laser Melting (SLM) of 304L stainless steel. The microstructure (porosity, grain size, and phase field) and engineering properties (density, modulus, and yield strength) depend on the thermal history during SLM manufacturing. Tensile test specimens have been built with a Renishaw AM250 using varied processing conditions to generate different thermal histories. SWIR imaging data is processed layer-to-layer to extract features in the thermal history for each process condition. The features in the thermal history are correlated with resulting part engineering properties, microstructure, and defects. The use of SWIR imaging is then discussed as a potential for processes monitoring to ensure part quality and develop layer-to-layer control in SLM.

This work was funded by Honeywell Federal Manufacturing & Technologies under Contract No. DE-NA0002839 with the U.S. Department of Energy.

null

['Wang, Yanshuo', 'Dong, Jian', 'Marcus, Harris L.']

2018-12-07T16:23:37Z

1997

Mechanical Engineering

doi:10.15781/T2VQ2SX0F

http://hdl.handle.net/2152/71447

eng

1997 International Solid Freeform Fabrication Symposium

Open

['SFF', '3D System']

The Use of VRML to Integrate Design and Solid Freeform Fabrication

Conference paper

https://repositories.lib.utexas.edu//bitstreams/d3feeffb-ad35-4525-98d3-732779a3d319/download

null

The Virtual Reality Modeling Language (VRML) was created to put interconnected 3D worlds onto every desktop. The 3D VRML format has the potential for 3D fax and TeleManufacture. An architecture and methodology of using VRML format to integrate a 3D model and Solid Freeform Fabrication system are described in this paper. The prototype software discussed in this paper demonstrates the use of VRML for Solid Freeform Fabrication process planning. The path used from design to part will be described.

null

['de Jager, P.J.', 'Broek, J.J.', 'Vergeest, J.S.M.']

2018-12-06T22:25:40Z

1997

Mechanical Engineering

doi:10.15781/T2571878Q

http://hdl.handle.net/2152/71437

eng

1997 International Solid Freeform Fabrication Symposium

Open

['zero order approximation', 'ruled slices']

Using adaptive ruled layers for Rapid Prototyping: principles and first results

Conference paper

https://repositories.lib.utexas.edu//bitstreams/1ba753a4-7bf4-4217-ae5d-689c239914d0/download

null

Current 2.5D layered rapid prototyping has as disadvantage the staircase effect, requiring thin layers to be used to achieve a reasonable accuracy. Slices with inclined outer surfaces can be constructed using linear interpolation between adjacent contours, resulting in ruled slices. A methodology to approximate a given model geometry within a specified accuracy using ruled slices and an adaptive layer thickness is described. This involves matching successive contours and analysing the geometry for curvature and inclination to calculate allowed layerthicknesses. First results show a significant reduction in the number of layers when compared to adaptive slicing using 2.5D layers. A proof-of-concept software, the Delft University of Technology Improved Slicer (DUTIS) has been developed to perform the adaptive slicing using either 2.5D or ruled layers allowing a comparison between the two alternative methods.

null

['Roach, R.A.', 'Bishop, J.E.', 'Johnson, K.', 'Rodgers, T.', 'Boyce, B.L.', 'Swiler, L.', 'van Bloemen Waanders, B.', 'Chandross, M.', 'Kammler, D.', 'Balch, D.', 'Jared, B.', 'Martinez, M.J.', 'Leathe, N.', 'Ford, K.']

2021-11-08T23:25:59Z

2018

Mechanical Engineering

null

['https://hdl.handle.net/2152/90074', 'http://dx.doi.org/10.26153/tsw/16995']

eng

2018 International Solid Freeform Fabrication Symposium

Open

['qualification paradigm', 'additive manufacturing', 'performance prediction', 'manufacturing control', 'cycles of learning']

Using Additive Manufacturing as a Pathway to Change the Qualification Paradigm

Conference paper

https://repositories.lib.utexas.edu//bitstreams/49b1be15-f305-4566-a461-1aebc2410aec/download

University of Texas at Austin

Additive Manufacturing (AM) offers the opportunity to transform design, manufacturing, and qualification with its unique capabilities. AM is a disruptive technology, allowing the capability to simultaneously create part and material while tightly controlling and monitoring the manufacturing process at the voxel level, with the inherent flexibility and agility in printing layer-by-layer. AM enables the possibility of measuring critical material and part parameters during manufacturing, thus changing the way we collect data, assess performance, and accept or qualify parts. It provides an opportunity to shift from the current iterative design-build-test qualification paradigm using traditional manufacturing processes to design-by-predictivity where requirements are addressed concurrently and rapidly. The new qualification paradigm driven by AM provides the opportunity to predict performance probabilistically, to optimally control the manufacturing process, and to implement accelerated cycles of learning. Exploiting these capabilities to realize a new uncertainty quantification-driven qualification that is rapid, flexible, and practical is the focus of this paper.

null

['Murphy, C.', 'Meisel, N.', 'Simpson, T.W.', 'McComb, C.']

2021-11-11T16:29:05Z

2018

Mechanical Engineering

null

['https://hdl.handle.net/2152/90237', 'http://dx.doi.org/10.26153/tsw/17158']

eng

2018 International Solid Freeform Fabrication Symposium

Open

['part mass', 'support material', 'build time', 'automation', 'deep learning', 'voxel patterns', 'design for additive manufacturing', 'DfAM']

Using Autoencoded Voxel Patterns to Predict Part Mass, Required Support Material, and Build Time

Conference paper

https://repositories.lib.utexas.edu//bitstreams/1d954d13-2bce-4293-b26e-b1ed67735a24/download

University of Texas at Austin

Additive Manufacturing (AM) allows designers to create intricate geometries that were once too complex or expensive to achieve through traditional manufacturing processes. Currently, designing parts using features specific to AM, commonly referred to as Design for Additive Manufacturing (DfAM), is restricted to experts in the field. As a result novices in industry may overlook potentially transformational design potential enabled by AM. This project aims to automate DfAM through deep learning making it accessible to a broader audience, and enabling designers of all skill levels to leverage unique AM geometries when creating new designs. To execute such an approach, a database of files was acquired from industry-sponsored AM challenges focused on lightweight design. These files were converted to a voxelized format, which provides more robust information for machine learning applications. Next, an autoencoder was constructed to a low-dimensional representation of the part designs. Finally, that autoencoder was used to construct a deep neural network capable of predicting various DfAM attributes. This work demonstrates a novel foray towards a more extensive DfAM support system that supports designers at all experience levels.

null

['Campbell, R.I.', 'de Beer, D.J.']

2021-09-23T22:32:47Z

9/10/08

Mechanical Engineering

null

['https://hdl.handle.net/2152/88040', 'http://dx.doi.org/10.26153/tsw/14981']

eng

2008 International Solid Freeform Fabrication Symposium

Open

['rapid prototyping models', 'customer interaction with functional prototypes', 'solid freeform fabrication']

Using Customer Interaction with Functional Prototypes to Support Innovative Product Development

Conference paper

https://repositories.lib.utexas.edu//bitstreams/dfeb7ae7-57f4-407d-8829-7045943da5f6/download

null

Rapid prototyping models have often been used to facilitate customer evaluation and approval of design concepts. This paper presents a method known as customer interaction with functional prototypes (CIFP) aimed at enabling customers to make a more creative input into the new product development process. The basic premise is that the solid freeform fabrication (SFF) technologies used for rapid manufacturing also enable more representative prototypes that can be used for full and frequent customer interaction in the design process. This paper reports an extended investigation where CIFP was used successfully within a small company to introduce a new range of innovative motion analysis products.

null

['Ma, Li', 'Fong, Jeffrey', 'Lane, Brandon', 'Moylan, Shawn', 'Filliben, James', 'Heckert, Alan', 'Levine, Lyle']

2021-10-19T18:49:07Z

2015

Mechanical Engineering

null

https://hdl.handle.net/2152/89322

eng

2014 International Solid Freeform Fabrication Symposium

Open

['laser powder bed fusion', 'finite element analysis', 'design of experiments', 'simulation parameters']

Using Design of Experiments in Finite Element Modeling to Identify Critical Variables for Laser Powder Bed Fusion

Conference paper

https://repositories.lib.utexas.edu//bitstreams/ac5b92ce-969b-41a1-b5c6-237041148bbe/download

University of Texas at Austin

Input of accurate material and simulation parameters is critical for accurate predictions in Laser Powder Bed Fusion (L-PBF) Finite Element Analysis (FEA). It is challenging and resource consuming to run experiments that measure and control all possible material properties and process parameters. In this research, we developed a 3-dimensional thermal L-PBF FEA model for a single track laser scan on one layer of metal powder above a solid metal substrate. We applied a design of experiments (DOE) approach which varies simulation parameters to identify critical variables in L-PBF. DOE is an exploratory tool for examining a large number of factors and alternative modeling approaches. It also determines which approaches can best predict L-PBF process performance.

null

['McKay, David S.', 'Davis, Hubert P.', 'Burns, Marshall']

2018-11-08T19:29:54Z

1996

Mechanical Engineering

doi:10.15781/T2VX06P12

http://hdl.handle.net/2152/69914

eng

1996 International Solid Freeform Fabrication Symposium

Open

['additive fabricators', 'technology', 'suitable fab processes']

Using Fabricators to Reduce Space Transportation Costs

Conference paper

https://repositories.lib.utexas.edu//bitstreams/443acc33-1c4a-4ef8-8e33-42aac5c2c126/download

null

Ever since the Apollo landings, one ofthe primary barriers to more ambitious space projects has been the exorbitant cost oflifting equipment and construction components off ofthe Earth. Fabricators offer an intriguing solution by allowing for the use of native materials on the Moon, Mars, or other destinations in the production of tool and building parts. This paper discusses • The kinds ofobjects that can be practically made in this fashion, • Fabricator processes suitable for extraterrestrial environments, • Raw materials available, and • The impact ofthis use oftechnology on the cost ofspace projects

null

Stucker, Brent

2020-03-10T16:31:48Z

2008

Mechanical Engineering

null

['https://hdl.handle.net/2152/80226', 'http://dx.doi.org/10.26153/tsw/7245']

eng

2008 International Solid Freeform Fabrication Symposium

Open

solid freeform fabrication

Using Literature Reviews as a Learning Tool for Solid Freeform Fabrication

Conference paper

https://repositories.lib.utexas.edu//bitstreams/c6fc8460-6846-4917-850e-51c0a8faf5fe/download

null

Over the past six years, students involved in the “Non-Traditional & Additive Manufacturing” course at Utah State University have been assigned an in-depth literature review as one their course projects. This literature review, done in groups of 2 or 3 students, involves becoming an expert on a topic of interest to the students and then presenting this material to the class as an indepth, oral presentation in addition to writing a journal-like review article on the topic. This project has proved to be a consistently effective method for enhancing learning of SFF technologies and their applications, and has been consistently noted by students in their course evaluations as a highly effective teaching tool. The methodology used for assigning and assessing these projects will be explored, in addition to a discussion of the benefits of this project toward meeting ABET criteria for accreditation of engineering programs.

null

['Fisher, Joseph W.', 'Miller, Simon W.', 'Bartolai, Joseph', 'Yukish, Michael A.']

2023-03-01T17:25:13Z

2022

Mechanical Engineering

null

['https://hdl.handle.net/2152/117551', 'http://dx.doi.org/10.26153/tsw/44431']

eng

2022 International Solid Freeform Fabrication Symposium

Open

Lattice Structure

Using Mean Curvature of Implicitly Defined Minimal Surface Approximations to Generate New Unit Cells for Lattice Design

Conference paper

https://repositories.lib.utexas.edu//bitstreams/ba44c249-babb-48e4-8213-5f2bb8e9aa98/download

null

Triply Periodic Minimal Surfaces (TPMS) are smoothly varying surfaces that exhibit zero mean curvature at all points on the surface. TPMS can be modeled with high accuracy us- ing discrete differential geometry techniques. However, generating a useful number of unit cells with this approach would be computationally expensive, and variable lattices would be impossible. Level sets of Fourier series approximations are often used instead. While these approximations have continuous geometry, they no longer retain zero mean curvature like the exact TPMS. In this paper, we calculate the mean curvature of the commonly used approximations of the gyroid and D-surface TPMS. Using isosurfaces of the mean curvature from these approximates, we define, similar but unique surface topologies. The development of these surfaces expands the list of lattices available to designers, broadening the lattice design space. Application to other approximations and further study of the application of these new surfaces is discussed.

null

['Williams, T.', 'Storti, D.', 'Ganter, M.']

2021-12-07T17:34:57Z

2021

Mechanical Engineering

null

['https://hdl.handle.net/2152/90732', 'http://dx.doi.org/10.26153/tsw/17651']

eng

2021 International Solid Freeform Fabrication Symposium

Open

['infill structures', 'Voronoi cell', 'medial surfaces', '3D printing']

Using Medial Surfaces to Produce Graded Voronoi Cell Infill Structures for 3D Printed Objects

Conference paper

https://repositories.lib.utexas.edu//bitstreams/e4fff7c6-fb17-4914-b51e-cec147447605/download

University of Texas at Austin

Many methods of additive manufacturing rely on infill structures to decrease part mass and print time. However, standard infill patterns generally use a uniform density or require time-consuming analysis to generate a density field tailored to part geometry. We propose a Voronoi cell based infill structure which uses the medial surfaces of the object to locate thin regions and increase local material density. The Voronoi cell structure reduces transition points within the infill, producing a more even gradient in density, while the weighting scheme ensures that traditionally weaker portions of the model receive adequate internal support.

null

['Penney, J.J.', 'Hamel, W.R.']

2021-11-30T19:20:22Z

2019

Mechanical Engineering

null

['https://hdl.handle.net/2152/90519', 'http://dx.doi.org/10.26153/tsw/17438']

eng

2019 International Solid Freeform Fabrication Symposium

Open

['large-scale additive manufacturing', 'non-gravity aligned', 'weld pool', 'metal parts']

Using Non-Gravity Aligned Welding in Large Scale Additive Metals Manufacturing for Building Complex Parts

Conference paper

https://repositories.lib.utexas.edu//bitstreams/9e5e084f-f3a8-4bd2-a70d-addb9314cd5b/download

University of Texas at Austin

One of the most difficult aspects of printing large, complex metal parts is building large overhangs without the use of support structures. When using typical gas metal arc welding techniques, the torch is kept aligned with the gravitational direction. It has been shown that the maximum overhang angle that can be achieved is roughly 25°. This maximum can be increased by using part positioner, but this adds extra system complexity, especially for creating the robot paths. It is desirable then to develop a method of printing with the torch in a Non-Gravity Aligned (NGA) direction, such that the weld pool is supported and will produce the desired weld bead. This work focuses on the development of a control scheme based on sensor feedback of the state of the weld pool to maintain a stable, desired weld pool shape and thus print more complex parts using the gas metal arc welding process.

null

['Williams, T.', 'Langehennig, S.', 'Ganter, M.', 'Storti, D.']

2021-11-30T19:30:46Z

2019

Mechanical Engineering

null

['https://hdl.handle.net/2152/90522', 'http://dx.doi.org/10.26153/tsw/17441']

eng

2019 International Solid Freeform Fabrication Symposium

Open

['3D printing', 'infill structures', 'support structures', 'Voronoi cells', 'algorithm']

Using Parallel Computing Techniques to Algorithmically Generate Voronoi Support and Infill Structures for 3D Printed Objects

Conference paper

https://repositories.lib.utexas.edu//bitstreams/4364fe80-082f-4f32-ab8b-89c70aefb3c6/download

University of Texas at Austin

Many methods of 3D printing rely on support and infill structures in order to produce quality parts. This paper formulates an algorithm that produces support and/or infill structures based on Voronoi cells for objects described by a function or a closed triangulated mesh. The algorithm utilizes Voronoi structures with a high degree of customization provided to the end user, and takes advantage of parallel computing to cut down on the computation time required to generate these structures. The aforementioned method is novel because it uses Voronoi structures as supports and combines support and infill generation into a single process, displaying the flexibility of Voronoi foam structures in 3D printing applications. The primary focus is the implementation of the algorithm itself and the customization capabilities it provides.

null

['Chesser, Phillip C.', 'Lind, Randall F.', 'Post, Brian K.', 'Roschli, Alex', 'Love, Lonnie J.', 'Gaul, Katherine T.']

2021-11-09T19:17:51Z

2018

Mechanical Engineering

null

['https://hdl.handle.net/2152/90139', 'http://dx.doi.org/10.26153/tsw/17060']

eng

2018 International Solid Freeform Fabrication Symposium

Open

['post-tensioning', 'z-strength', 'load bearing structures', 'large scale additive manufacturing', 'big area additive manufacturing', 'BAAM']

Using Post-Tensioning in Large Scale Additive Parts for Load Bearing Structures

Conference paper

https://repositories.lib.utexas.edu//bitstreams/df48b008-29f9-4c58-a574-cb1446ee4a6a/download

University of Texas at Austin

One of the perennial problems with additive manufacturing (AM) is the lack of inter-laminar bond strength between the layers, also known as z-strength. This can make the use of AM fabricated parts in load bearing applications problematic. This problem can be solved in some applications with post-tensioning. The use of post-tensioning in structures can be used to ensure that layer interfaces only see compressive stresses. This method is commonly used to strengthen concrete structures since concrete is weak in tension while strong in compression. This paper explores the successful application of post-tensioning to improve z-strength of large structures made with Big Area Additive Manufacturing (BAAM) where loads are significant. Theory and examples are presented herein.

null

['Messing, Andrew', 'Roschli, Alex', 'Post, Brian K.', 'Love, Lonnie J.']

2021-11-02T20:12:03Z

2017

Mechanical Engineering

null

https://hdl.handle.net/2152/89884

eng

2017 International Solid Freeform Fabrication Symposium

Open

['skeletons', 'void filling', 'overfilling', 'underfilling', 'large-scale additive manufacturing', 'skeletonization']

Using Skeletons for Void Filling in Large-Scale Additive Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/66745bc5-1e9b-4d7b-854f-3fa145896fce/download

University of Texas at Austin

In additive manufacturing (AM), slicing software is used to generate tool paths that are then converted to G-Code, which tells the 3D printer how to build a part. Toolpaths are generated using closed-loop paths. Sometimes the space left for a closed-loop is not sized perfectly. This can lead to overfill or underfill issues. Therefore, skeletonization of a polygon seeks to resolve this issue by creating an open-loop path to fill the voids between adjacent toolpaths. A straight skeleton was used to explore this work. Straight skeletonization represents the topological skeleton of a shape through line segments. After skeletonization, the extrusion rate can be varied to adjust bead width more precisely to fill the gap.

null

['Dwivedi, Rajeev', 'Shah, Parthiv', 'Bhupathiraju, Rohit', 'Dwivedi, Indira', 'Dwivedi, Bharat', 'Agarwal, Anvita', 'Rebbapragada, Arun Skanda', 'Agarwal, Ria', 'Singh, Nehal', 'Bhupathiraju, Ravi', 'Rebbapragada, Surya']

2023-01-26T21:47:28Z

2022

Mechanical Engineering

null

['https://hdl.handle.net/2152/117325', 'http://dx.doi.org/10.26153/tsw/44206']

eng

2022 International Solid Freeform Fabrication Symposium

Open

robotics

Using Solid Freeform Fabrication to develop a low-cost Robotics experiment platform to complement classroom learning and exploring topics in STEM Education

Conference paper

https://repositories.lib.utexas.edu//bitstreams/d076310d-892a-4f12-8c4f-d58ae7af785f/download

null

Educational and competitive robotics provide avenue for hands on experimentation and hence effective tools for STEM education. Cost of physical components continues to be a limiting factor. Within the Educational Robotics, the kits (LEGO, VEX, REV, etc.) are beyond the reach of most of the communities across the world. “Robotics for All” is an initiative to enable a versatile cost-effective platform to provide a minimum set of parts that students can integrate with general purpose as well as custom controller/microcomputers (Arduino, Raspberry-Pi, BBC microbit) to perform range of experiments. Various sensors and camera modules can be easily integrated to further learning and experimentation. It will be possible to perform experiments in Robot Navigation, Process planning, object manipulation, industrial architectures, Machine Learning etc. Solid Freeform Fabrication was used to enable manufacturing, verification and improve the design of piece parts with emphasis on low cost without compromise on learning opportunities.

null

['Andrew, K.', 'Weaver, J.M.']

2021-11-30T20:59:13Z

2019

Mechanical Engineering

null

['https://hdl.handle.net/2152/90546', 'http://dx.doi.org/10.26153/tsw/17465']

eng

2019 International Solid Freeform Fabrication Symposium

Open

['wax filament', 'castings', 'fused filament fabrication']

Using Wax Filament Additive Manufacturing for Low-Volume Investment Casting

Conference paper

https://repositories.lib.utexas.edu//bitstreams/eb66d4d1-ef76-48fc-b0ae-6d572d75bb99/download

University of Texas at Austin

Investment casting is a popular method of converting wax or polymer patterns into metal objects. For low-volumes these patterns can be manufactured using additive manufacturing. However, burning out conventional additive thermoplastics like PLA can be more problematic than removing wax. Often these plastics leave ash residue on the cavity surface, leading to defects in the final metal part. Possible solutions to this problem include using ash-free materials like wax or adjusting parameters to lessen ash buildup. With sufficient consistency in quality, investment casting can be an attractive alternative to metal additive processes. This paper discusses using wax filament on a conventional desktop fused filament fabrication (FFF) additive machine, including discoveries, settings, and design guidelines leading to successful wax prints. The resulting wax filament castings are compared to identical castings produced from colored PLA, and advantages and disadvantages of using wax filament are discussed.

null

['Almusaied, Zaid', 'Asiabanpour, Bahram']

2021-12-01T21:40:20Z

2021

Mechanical Engineering

null

['https://hdl.handle.net/2152/90622', 'http://dx.doi.org/10.26153/tsw/17541']

eng

2021 International Solid Freeform Fabrication Symposium

Open

['additive manufacturing', 'atmospheric water generator', 'thermoacoustic refrigeration']

Utilizing Additive Manufacturing in Thermoacoustic Refrigeration-based Atmospheric Water Generation

Conference paper

https://repositories.lib.utexas.edu//bitstreams/bfaaed40-1e6c-408a-8362-614fb53cc040/download

University of Texas at Austin

Atmospheric water generators are devices that generate water by condensation. The water vapor in the air is cooled, by a refrigeration system, below the dew point and thus forces a phase transfer from gaseous to liquid. Thermoacoustic refrigeration (TAR) was used as the refrigeration technology. The TAR is an innovative clean technology that utilizes an acoustic wave passing through a gas to create a temperature gradient in a specially designed porous material. The main components of such a system are resonator tube, stack, acoustic driver, gas, and heat exchangers. An additive manufacturing process was utilized to develop different configurations and interchangeable components of the TAR system. The lowest temperature on the cold side of the stack was achieved by the stack manufactured with spiral design, spacing of 0.53 mm, 4cm length, and 1cm stack position in the resonator tube. The minimum temperature achieved with this prototype was around 46 ̊F at a room temperature of 72 ̊F, relative humidity of 59%, and dew point of 57 ̊ F.

null

['Smith, C.J.', 'Todd, I.', 'Gilbert, M.']

2021-10-12T18:09:38Z

2013

Mechanical Engineering

null

['https://hdl.handle.net/2152/88710', 'http://dx.doi.org/10.26153/tsw/15644']

eng

2013 International Solid Freeform Fabrication Symposium

Open

['structural optimization', 'additive manufacturing', 'load testing', 'load carrying capacity', 'layout optimization', 'Ti-6Al-4V', 'titanium']

Utilizing Additive Manufacturing Techniques to Fabricate Weight Optimized Components Designed using Structural Optimization Methods

Conference paper

https://repositories.lib.utexas.edu//bitstreams/eaf8e8c8-f7d0-423e-b154-ea7afca4db0b/download

University of Texas at Austin

This paper describes a preliminary study of the application of structural optimization techniques to the design of additively manufactured components, using load testing to failure to establish true load carrying capacity. The cantilever component specimens fabricated were designed to resist a tip load and comprised one conventional benchmark design and two designs developed using layout optimization (LO) techniques. The designs were fabricated from Titanium Ti-6Al-4V and then scanned for internal defects using X-Ray Computed Tomography (XCT). All three specimens failed below the design load during testing. Several issues were identified in both the design optimization and fabrication phases of the work, contributing to the premature failure of the specimens. Various recommendations to improve the optimization phase are presented in the paper.

null

['Alshaikh Ali, Mohammad', 'Fidan, Ismail', 'Allen, Michael', 'Bhattacharya, Indranil', 'Tantawi, Khalid']

2023-03-01T17:21:29Z

2022

Mechanical Engineering

null

['https://hdl.handle.net/2152/117550', 'http://dx.doi.org/10.26153/tsw/44430']

eng

2022 International Solid Freeform Fabrication Symposium

Open

['Additive Manufacturing', 'Stereolithography', 'Fused Filament Fabrication', 'Lattice Structure', 'Energy Consumption']

Utilizing Lattice Infill Structures to Optimize Weight with Structural Integrity Investigation for Commonly Used 3D Printing Technologies

Conference paper

https://repositories.lib.utexas.edu//bitstreams/9c9a93b3-95b0-45c2-ac50-5ad41979bce3/download

null

Additive Manufacturing (AM) is utilized in various applications and fields. This research study investigates the use of lattice infill structures to reduce weight in two commonly used AM methods; Stereolithography (SLA) and Fused Filament Fabrication (FFF). Structural integrity of lattice infilled parts is investigated. Before utilizing lattice infill structures, different process parameters are also investigated to gain a knowledge base for these patterns’ effect on weight and power consumption (PC). Cubes are used as test specimens to perform the knowledge base study for the process parameters. Based on the initial study, an infill pattern is chosen to be compared with a lattice infill structure. The test specimens for this study are chosen to be of different background and complexity. Experimental data indicates a reduction in weight with no increase in PC for SLA and an increase in PC for FFF. Lattice infilled structures respond well to structural integrity testing.

null

['Brackett, D.J.', 'Ashcroft, I.A.', 'Hague, R.J.']

2021-09-23T22:43:01Z

9/10/08

Mechanical Engineering

null

['https://hdl.handle.net/2152/88043', 'http://dx.doi.org/10.26153/tsw/14984']

eng

2008 International Solid Freeform Fabrication Symposium

Open

['brass musical instruments', 'Rapid Manufacturing', 'structural interactions', 'acoustical interactions']

Utilizing the Design Freedoms of Rapid Manufacturing to Optimise Structural and Acoustal Interactions of 'Brass' Musical Instruments

Conference paper

https://repositories.lib.utexas.edu//bitstreams/bd809bd5-a3da-4bf0-bc9b-dbebc838cff1/download

null

The feasibility of the production of end use ‘brass’ musical instruments using Rapid Manufacturing (RM) is discussed with an emphasis on optimising the structural resonance through stiffening structures. The method is based upon a coupling between the air-column and structure when their resonant frequencies approach each other, which accentuates the players’ lip to wall coupling effect. The degree of wall vibration and the frequencies at which it occurs can be controlled by variation of the structure’s stiffness and the design freedoms allowed by RM enable greater control of this. Initial results of the structures and their performance are presented.

null

['Rock, Stephen J.', 'Wozny, Michael J.']

2018-04-12T18:14:16Z

1991

Mechanical Engineering

doi:10.15781/T2FN1186X

http://hdl.handle.net/2152/64278

eng

1991 International Solid Freeform Fabrication Symposium

Open

['Rensselaer Design Research Center', 'Rensselaer Polytechnic Institute', 'SFF', 'SLS']

Utilizing Topological Information to Increase Scan Vector Generation Efficiency

Conference paper

https://repositories.lib.utexas.edu//bitstreams/a2840b89-2588-46e1-915d-fd4581fc8b27/download

null

Demands for increased Solid Freeform Fabrication precision and speed suggest the need for advanced scanning techniques, such as boundary tracing, half-lap and multiple orientation scanning, or 'intel nt' scanning. Since most SFF processes construct parts from parallel material layers, separating model slicing and scan conversion functions appears to be a powerful approach. Both can benefit from increased topological information. This paper addresses the issue of improving model slicing by utilizing topological data to increase performance, and consequently, improve the efficiency with which scan vectors can be generated.

null

['Starly, B.', 'Chang, R.', 'Sun, W.']

2020-02-27T20:22:08Z

2006

Mechanical Engineering

null

['https://hdl.handle.net/2152/80100', 'http://dx.doi.org/10.26153/tsw/7121']

eng

2006 International Solid Freeform Fabrication Symposium

Open

poly-ethylene diacrylate

UV-Photolithography Fabrication of Poly-Ethylene Glycol Hydrogels Encapsulated with Hepatocytes

Conference paper

https://repositories.lib.utexas.edu//bitstreams/d2fdbd6b-7c80-4243-9153-3d78df881292/download

null

The development of biomanufacturing technologies particularly, layered manufacturing has advanced cell encapsulation processes in an effort to mimic the cellular microenvironment for invitro studies. This paper illustrates an inexpensive UV-photolithographic method for encapsulation of human hepatocytes in three dimensional structures using poly-ethylene diacrylate (PEGDA) hydrogels as candidate substrates. In order to further develop this technology for layered fabrication, we have quantified the long-term effects of the photo-initiator concentration and UV light exposure on the metabolic rates of encapsulated human hepatocytes under a 21 day study. The photoinitator toxicity was observed immediately after polymerization with no significant cytotoxicity on a long term basis. A cellular viability is examined and reported for the UV photopolymerization process. Cell phenotype maintenance was observed by measuring the amount of urea produced over a 1 week time period. This photo encapsulation process may find use in the fabrication of spatially complex 3D scaffolds for tissue engineering applications, elucidation of the 3D structure-pharmacokinetic response relationship and the fabrication of complex multi-compartment liver tissue analog devices for drug screening applications.

null

['Butcher, D.', 'Christie, S.', 'Brown, S.G.R.', 'Lavery, N.P.']

2021-11-18T17:15:53Z

2019

Mechanical Engineering

null

['https://hdl.handle.net/2152/90433', 'http://dx.doi.org/10.26153/tsw/17354']

eng

2019 International Solid Freeform Fabrication Symposium

Open

['melt pool ejecta', 'mechanical properties', 'build failure', 'computational modelling technique', 'laser powder bed fusion']

Validated Computational Modelling Techniques for Simulating Melt Pool Ejecta In Laser Powder Bed Fusion Processing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/53db1677-0fd4-4151-b2f8-cd6e4b5d8338/download

University of Texas at Austin

Industry currently require faster build rates from laser powder bed fusion processes. As such, higher power lasers and multi-laser systems are being explored. Due to instabilities in the melting process, material is ejected from the melt pool in the form of spatter and vapour. Previous work has shown that these ‘ejecta’ can result in attenuation of the laser and redeposition of lager particles onto the powder bed; which can lead to poor mechanical properties. ANSYS Fluent was used to create a CFD model which was validated against hot wire anemometry results from Renishaw’s RenAM 500Q. This was then coupled with a Discrete Phase Model (DPM) to track the ejection of spatter and vapour from the melt pool through the chamber. This has led to a better understanding of the removal of ‘ejecta’, leading to increased mechanical properties and lower rates of build failure.

null

['Bhate, D.', 'Van Soest, J.', 'Reeher, J.', 'Patel, D.', 'Gibson, D.', 'Gerbasi, J.', 'Finfrock, M.']

2021-11-01T21:13:31Z

2016

Mechanical Engineering

null

https://hdl.handle.net/2152/89755

eng

2016 International Solid Freeform Fabrication Symposium

Open

['elastic response', 'ULTEM-9085', 'honeycomb structures', 'methodology', 'fused deposition modeling']

A Validated Methodology for Predicting the Mechanical Behavior of Ultem-9085 Honeycomb Structures Manufactured by Fused Deposition Modeling

Conference paper

https://repositories.lib.utexas.edu//bitstreams/3a0ccfed-8a6d-4bef-8cf4-13da387a3bff/download

University of Texas at Austin

ULTEM-9085 has established itself as the Additive Manufacturing (AM) polymer of choice for end-use applications such as ducts, housings, brackets and shrouds. The design freedom enabled by AM processes has allowed us to build structures with complex internal lattice structures to enhance part performance. While solutions exist for designing and manufacturing cellular structures, there are no reliable ways to predict their behavior that account for both the geometric and process complexity of these structures. In this work, we first show how the use of published values of elastic modulus for ULTEM-9085 honeycomb structures in FE simulation results in 40- 60% error in the predicted elastic response. We then develop a methodology that combines experimental, analytical and numerical techniques to predict elastic response within a 5% error. We believe our methodology is extendable to other processes, materials and geometries and discuss future work in this regard.

null

['Moritzer, E.', 'Hecker, F.']

2023-04-05T13:59:39Z

2022

Mechanical Engineering

null

['https://hdl.handle.net/2152/117778', 'http://dx.doi.org/10.26153/tsw/44657']

eng

2022 International Solid Freeform Fabrication Symposium

Open

FEM

Validation and Comparison of Fem-Simulation Results of the Fused Deposition Modeling Process under Consideration of Different Mesh Resolutions

Conference paper

https://repositories.lib.utexas.edu//bitstreams/e3f1547e-e8b2-4a16-b8aa-035ec4b83f7c/download

null

The Fused Deposition Modeling (FDM) process is an Additive Manufacturing (AM) technology. In the FDM process, components are generated by feeding a thermoplastic polymer filament into a heated nozzle and depositing the molten material layer-by-layer in a defined way onto the building platform or an already existing component structure. The strand-by- strand deposition leads to a complex cooling situation which contributes to the non-uniform shrinkage of components in the FDM-process. Using an AM plug-in for the FEM-simulation software Abaqus, the thermal and mechanical aspects of a component can be simulated according to the temporal sequence of the manufacturing process. For this, the birth-death- method is used in the simulations. During the investigations, the simulation results regarding geometrical deviations are compared to the actual deviation of the manufactured specimens. Furthermore, the influences of the mesh resolution on the simulation results and the required time for the simulations are considered.

null

['Schley, C.', 'Smith, G.F.']

2018-12-07T16:09:50Z

1997

Mechanical Engineering

doi:10.15781/T2CN6ZK4F

http://hdl.handle.net/2152/71443

eng

1997 International Solid Freeform Fabrication Symposium

Open

['FEA', 'rapid prototyping']

Validation of Rapid Prototyping Material for Rapid Experimental Stress Analysis

Conference paper

https://repositories.lib.utexas.edu//bitstreams/bfa3627d-056c-49f3-b0e6-488b5c7384c2/download

null

The paper will detail the validation work carried out on various Rapid Prototyping (RP) materials to determine their suitability for the application of Thermoelastic Stress Analysis. The overall objective is to drastically reduce the product design cycle, by providing "real experimental data" for correlation with Finite Element Analysis (FEA), prior to any expensive manufacturing process. In order to achieve this the homogeneity of the Rapid Prototyping material has to be established to ensure a valid transfer of results from model to actual part.

null

['Cooke, A.L.', 'Soons, J.A.']

2021-09-29T22:20:23Z

2010

Mechanical Engineering

null

['https://hdl.handle.net/2152/88219', 'http://dx.doi.org/10.26153/tsw/15160']

eng

2010 International Solid Freeform Fabrication Symposium

Open

['geometric accuracy', 'variability', 'metal test part', 'electron beam', 'laser beam', 'powder bed', 'thermal fusion process', 'additive manufacturing']

Variability in the Geometric Accuracy of Additively Manufactured Test Parts

Conference paper

https://repositories.lib.utexas.edu//bitstreams/24f35ec3-3fc8-4f8d-af01-5bce5a617d49/download

University of Texas at Austin

This paper describes the results of a study on the variability in the geometric accuracy of a metal test part manufactured by several service providers using either an electron beam or laser beam powder bed thermal fusion process. The part was a circle-diamond-square test part with an inverted cone that is used to evaluate the performance of five-axis milling machines. The study was conducted to aid development of standardized parameters and test methods to specify and evaluate the performance of additive manufacturing systems. Without standards for performance characterization, it is difficult to match system capabilities with part requirements and ensure consistent and predictable part quality across systems, operators, and manufacturing facilities.

null

['Faes, M.', 'Wang, Y.', 'Lava, P.', 'Moens, D.']

2021-10-20T22:57:22Z

2015

Mechanical Engineering

null

https://hdl.handle.net/2152/89383

eng

2015 International Solid Freeform Fabrication Symposium

Open

['laser sintering', 'PA-12', 'mechanical variability', 'non-deterministic']

Variability in the Mechanical Properties of Laser Sintered PA-12 Components

Conference paper

https://repositories.lib.utexas.edu//bitstreams/b03021d3-f8a4-4868-b64c-324c83e9294c/download

University of Texas at Austin

The quasi-static mechanical properties of Laser Sintered (LS) PA-12 material are highly influenced by the thermal history of the thermoplastic material during the production, as this impacts critical material properties such as the degree of crystallinity and porosity in the resulting component. Many process-related parameters, including preheating temperature, laser energy density, layer interaction time and post-build cooling cycle, were already shown to influence the thermal history significantly. Due to the large, mainly epistemic, variability in these parameters, the mechanical response of produced components is often difficult to predict and is moreover governed by non-isotropic constitutive equations. This work therefore focusses on the identification of this variability in the mechanical behavior and the validation of experimentally obtained non-deterministic material models. A non-deterministic (variable) constitutive model is built experimentally, based on 90 uniaxial tensile tests, performed on LS samples that were built under different orientations. This model is subsequently validated by building a well-defined benchmark sample, containing complex stress states upon loading. This sample is tested using Digital Image Correlation. Finally, a novel way of identifying non-isotropic material properties, the Virtual Fields Method, is applied to this benchmark sample to identify the constitutive parameters.

null

['Habbal, Osama', 'Ayoub, Georges', 'Pannier, Christopher']

2021-12-07T18:15:39Z

2021

Mechanical Engineering

null

['https://hdl.handle.net/2152/90745', 'http://dx.doi.org/10.26153/tsw/17664']

eng

2021 International Solid Freeform Fabrication Symposium

Open

['variable extrusion width', 'bead ith', 'bead trajectory', 'in-plane strength', 'fused filament fabrication', 'additive manufacturing']

Variable Extrusion Width for Interlocking Features in Fused Filament Fabrication 3D Printing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/e8c67a6f-f4f2-43f1-9b81-6b3de8a9b4e3/download

University of Texas at Austin

Following from developments in continuously variable extrusion width in fused filament fabrication additive manufacturing, this work explores the combination of in-plane bead width variation with bead trajectory variation as a technique to improve in-plane strength in polymer material extrusion additive manufacturing. Sinusoidal in-plane waveforms are used for the extruder trajectory instead of maintaining a straight line. The varied bead width, in conjunction with the non-straight bead trajectory, reduces anisotropy of strength within the layer. The findings apply to fully dense infill of single layers, commonly called horizontal perimeters in common slicing/toolpath planning computer programs. Experimental tensile testing results show a 48.6% reduction in anisotropy of tensile strength driven by 43% and 29% increases in the ultimate tensile strength in the 0° and 45° orientations, respectively. However, this comes at the cost of 99.6% reduction in toughness in the 90° orientation. We also present the principal concept behind the machine code generating script, that allows for the increase and decrease of the extruded bead width continuously along the extruded bead.

null

['Wang, Huijun', 'Kovacevic, Radovan']

2019-09-23T16:38:29Z

2000

Mechanical Engineering

null

['https://hdl.handle.net/2152/75961', 'http://dx.doi.org/10.26153/tsw/3060']

eng

2000 International Solid Freeform Fabrication Symposium

Open

Prototyping

Variable Polarity GTAW in Rapid Prototyping of Aluminum Parts 369

Conference paper

https://repositories.lib.utexas.edu//bitstreams/e3269e05-3388-484c-a408-2f090de60ad5/download

null

This paper reports on a process to build aluminum alloy parts by variable polarity gas tungsten arc welding (GTAW). The relationship between the geometric sizes of the deposited layer and the welding parameters is investigated. A machine vision sensor is used to monitor and control the arc length that is a key welding parameter in the achievement of uniform deposition. By optimizing the depositing speed and the depositing layer thickness, there is no need for a cooling system to cool the part. Three Dimensional parts with different wall widths and different shapes are successfully obtained. The surfaces of the deposited aluminum parts are smooth and uniform.

null

['Tang, Lie', 'Ruan, Jianzhong', 'Landers, Robert G.', 'Liou, Frank']

2020-03-09T13:19:56Z

8/21/07

Mechanical Engineering

null

['https://hdl.handle.net/2152/80172', 'http://dx.doi.org/10.26153/tsw/7191']

eng

2007 International Solid Freeform Fabrication Symposium

Open

Variable Powder Flow Rate Control

Variable Powder Flow Rate Control in Laser Metal Deposition Processes

Conference paper

https://repositories.lib.utexas.edu//bitstreams/67a7a7c8-7927-47dd-9cf3-b35b197ac980/download

null

This paper proposes a novel technique, called Variable Powder Flow Rate Control (VPFRC), for the regulation of powder flow rate in laser metal deposition processes. The idea of VPFRC is to adjust the powder flow rate to maintain a uniform powder deposition per unit length even when disturbances occur (e.g., the motion system accelerates and decelerates). Dynamic models of the powder delivery system motor and the powder transport system (i.e., five–meter pipe, powder dispenser, and cladding head) are first constructed. A general tracking controller is then designed to track variable powder flow rate references. Since the powder flow rate at the nozzle exit cannot be directly measured, it is estimated using the powder transport system model. The input to this model is the DC motor rotation speed, which is estimated on–line using a Kalman filter. Experiments are conducted to examine the performance of the proposed control methodology. The experimental results demonstrate that VPFRC is successful in maintaining a uniform track morphology, even when the motion control system accelerates and decelerates.

null

['Chamberlain, Peter B.', 'Roosendaal, Mark D. Van', 'Thomas, Charles L.']

2019-02-22T17:47:52Z

1998

Mechanical Engineering

null

['https://hdl.handle.net/2152/73464', 'http://dx.doi.org/10.26153/tsw/614']

eng

1998 International Solid Freeform Fabrication Symposium

Open

['rapid prototyping', '(zero order)']

Variable Thickness Ruled Edge Slice Generation and Three-Dimensional Graphical Error Visualization

Conference paper

https://repositories.lib.utexas.edu//bitstreams/bd305342-f346-4d9b-9216-844582d05473/download

null

This paper describes a simple variable thickness ruled edged slicing algorithm that produces slices with zero integrated error. In its present state, the algorithm requires presampled data to be taken from the STL file. Data points are extracted in a cylindrical coordinate system giving values ofradius at regular intervals AS and Az. Using this data, the algorithm creates slices based on averaging ofthe data points and the slope ofline segments connecting them. Error based constraints are used to determine slice thickness. A three-dimensional visualization technique using color contour plots (representing error) on the surface ofthe prototyped model provides a means of evaluating the accuracy of the prototyped part.

null

['Whetten, S.R.', 'Lavin, J.M.', 'Keicher, D.M.', 'Appelhans, L.N.', 'Essien, M.', 'Mani, S.S.', 'Moore, P.B.', 'Cook, A.', 'Acree, N.A.', 'Young, N.P.', 'Russell, M.J.']

2021-10-28T20:29:05Z

2016

Mechanical Engineering

null

https://hdl.handle.net/2152/89692

eng

2016 International Solid Freeform Fabrication Symposium

Open

['process variables', 'feature definition', 'polyimide films', 'film production', 'syringe deposition printing', 'direct write printing']

Variables Impacting Feature Definition of Polyimide Using Syringe Based Printing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/e4811f33-ee39-428f-a314-92b5051bf211/download

University of Texas at Austin

Direct write printing approaches provide an opportunity for additive manufacturing (AM) to impact the electronics industry through cost effective prototyping and manufacturing. Direct write printing of electronics also provides the opportunity for the electronics industry to be impacted by such things as new material research, fewer steps in processing, along with application specific packaging and component configuration. This paper illustrates how process variables affect the feature definition of polyimide film production via syringe deposition printing. This work compares the films as the process variables change, and describes which variables make the greatest impact on feature definition.

null

['Heigel, J.C.', 'Lane, B.M.', 'Moylan, S.P.']

2021-10-28T21:32:08Z

2016

Mechanical Engineering

null

https://hdl.handle.net/2152/89703

eng

2016 International Solid Freeform Fabrication Symposium

Open

['emmittivity', 'infrared camera', 'powder bed fusion', 'build parameters']

Variation of Emittivity with Powder Bed Fusion Build Parameters

Conference paper

https://repositories.lib.utexas.edu//bitstreams/037307b8-2042-44b2-9e83-16ae458f48e2/download

University of Texas at Austin

Common approaches to process monitoring of powder bed fusion rely heavily on optical measurements. These measurements can be used to verify powder spreading, assess the quality of each layer, and measure process temperatures. In regards to the latter, radiometric detectors such as cameras or pyrometers only measure radiant emissions from the surface, and do not directly measure its temperature. Calculating the temperature from these measurements relies on the calibration of the camera or pyrometer with a blackbody and on knowledge of the emittivity of the surface being measured. Emittivity depends on multiple factors including surface texture and viewing angle, among others. An apparatus and method for measuring emittivity using an infrared camera is detailed. Measured emittivity values from metal surfaces produced using a commercial powder bed fusion process are presented and related to temperature, viewing angle, and oxidation state.

null

['Xu, Changxue', 'Huang, Yong', 'Markwald, Roger R.']

2021-10-05T19:13:14Z

2012

Mechanical Engineering

null

['https://hdl.handle.net/2152/88413', 'http://dx.doi.org/10.26153/tsw/15352']

eng

2012 International Solid Freeform Fabrication Symposium

Open

['organ printing', 'tissue engineering', 'vascular constructs', 'vertical 3D printing', 'horizontal 3D printing']

Vertical and Horizontal Fabrication of Alginate-Based Vascular-Like Constructs Using Inkjetting

Conference paper

https://repositories.lib.utexas.edu//bitstreams/561224e4-f4f2-469f-9d77-d9e4eba0530e/download

University of Texas at Austin

Organ printing, among different tissue engineering innovations, is a layer-by-layer additive fabrication approach for making three-dimensional (3D) tissue and organ constructs using cellular spheroids or bioink as building blocks. The capability to fabricate 3D cellular tubes is the first step as well as an important indicator of the overall feasibility of envisioned organ printing technology. In this study, vascular-like alginate tubes with a hemi-branching point, which mimic typical vascular constructs, are fabricated both vertically and horizontally using drop-on-demand inkjetting. In addition, manufacturing challenges associated with the vertical and horizontal printing configurations are briefly discussed. This study lays a foundation for the effective and efficient fabrication of viable 3D vascular constructs with complex anatomies (e.g. branching) as required in organ printing of vascular trees.

null

['Frye, Palmer', 'Muhammad, Muztahid', 'Simsiriwong, Jutima', 'Shamsaei, Nima']

2021-11-18T00:40:51Z

2019

Mechanical Engineering

null

['https://hdl.handle.net/2152/90375', 'http://dx.doi.org/10.26153/tsw/17296']

eng

2019 International Solid Freeform Fabrication Symposium

Open

['very high cycle fatigue', 'VHCF', 'Inconel 718', 'laser beam powder bed fusion', 'LB-PBF']

Very High Cycle Fatigue Behavior of Laser Beam-Powder Bed Fused Inconel 718

Conference paper

https://repositories.lib.utexas.edu//bitstreams/ace5a1f3-7b9e-45ca-80ad-eabcb3e0fbc2/download

University of Texas at Austin

In this study, the very high cycle fatigue (VHCF) behavior of Inconel 718 manufactured via a Laser Beam-Powder Bed Fusion (LB-PBF) process is investigated. LB-PBF Inconel 718 specimens are fabricated in vertical direction and subjected to post-processing heat treatment. The experiment is conducted on as built (i.e. non-machined) specimens utilizing an ultrasonic fatigue test system operating at 20 kHz under force-controlled fully-reversed constant amplitude cyclic loading. Fractography analysis is performed using a digital microscope to identify microstructural features that initiate fatigue cracks in the specimens. Experimental results from LB-PBF Inconel 718 specimens are presented and compared to those of wrought Inconel 718. It is determined that the fatigue resistance of as-built LB-PBF Inconel 718 specimens is significantly less than that of the wrought material. This result is attributed to a large presence of LB-PBF process intrinsic defects. In the VHCF regime, subsurface crack initiation is the primary fatigue failure mechanism in as-built LB-PBF Inconel 718 specimens.

null

['Cohen, A.', 'Chen, R.', 'Frodis, U.', 'Wu, M.', 'Folk, C.']

2021-09-29T17:30:57Z

2009-09

Mechanical Engineering

null

['https://hdl.handle.net/2152/88196', 'http://dx.doi.org/10.26153/tsw/15137']

eng

2009 International Solid Freeform Fabrication Symposium

Open

['metal micro-mechanisms', 'minimally-invasive medical devices', 'EFAB process']

Wafer-Scale, Solid Freeform Fabrication of Fully-Assembled Metal Micro-Mechanisms for Minimally-Invasive Medical Devices

Conference paper

https://repositories.lib.utexas.edu//bitstreams/1e4e37c1-3fae-4bd1-b69e-0d8a2eb9e5af/download

University of Texas at Austin

The EFAB process was first presented at the SFF Symposium in 1998, at a very early stage of its development. Currently, the technology is able to produce complex 3-D devices— including mechanisms built pre-assembled—in production volumes, using a three-step process of selective electrodeposition of one metal, blanket electrodeposition of another metal, and planarization. Layer thickness is as small as 4 µm, minimum feature size is down to 10 µm, and linear tolerances are ~2 µm. Metals are biocompatible materials with mechanical properties similar to stainless steel. The technology enables new instruments for minimally-invasive surgical and interventional procedures.

null

['Arthur, Alan', 'Dickens, Phill', 'Bocking, Chris', 'Cobb, Richard']

2018-11-09T16:42:44Z

1996

Mechanical Engineering

doi:10.15781/T2DR2PV2K

http://hdl.handle.net/2152/69935

eng

1996 International Solid Freeform Fabrication Symposium

Open

['SL', 'RP', 'EDM']

Wear & Failure Mechanisms for SL EDM Electrodes

Conference paper

https://repositories.lib.utexas.edu//bitstreams/fee0dcd9-545e-4728-9266-7fb345b23377/download

null

The principle of Electro-Discharge Machining (EDM) electrode manufacture using rapid prototyped Stereo Lithography (SL) models has been proposed and discussed in previous published material by the authors [1,2,3,4]. Applying a thin electrodeposited coating of copper to SL models has provided a direct route from model to tool cavity. A number of current factors present limitations to the application of these electrodes. This paper outlines and addresses the factors affecting electrode quality and performance. Premature failure of SL electrodes is attributed to a number of wear and failure mechanisms which are being investigated at The University of Nottingham. An overview of experimental and theoretical work is presented.

null

['Kumar, S.', 'Kruth, J.-P.', 'Froyen, L.']

2021-09-23T22:35:20Z

9/10/08

Mechanical Engineering

null

['https://hdl.handle.net/2152/88041', 'http://dx.doi.org/10.26153/tsw/14982']

eng

2008 International Solid Freeform Fabrication Symposium

Open

['Selective Laser Sintering', 'SLS', 'WC-Co-Cu', 'fretting wear']

Wear Behaviour of SLS WC-Co Composites

Conference paper

https://repositories.lib.utexas.edu//bitstreams/4b147645-f8c1-43c7-a3b9-89c599dcc46e/download

null

text

null

Kumar, S.

2020-03-10T17:44:02Z

2008

Mechanical Engineering

null

['https://hdl.handle.net/2152/80240', 'http://dx.doi.org/10.26153/tsw/7259']

eng

2008 International Solid Freeform Fabrication Symposium

Open

Selective Laser Sintering

Wear of SLS Materials under Plastic and Elastic Contact Conditions

Conference paper

https://repositories.lib.utexas.edu//bitstreams/fc6f8017-a963-4a41-a007-411c7ea85521/download

null

Sliding wear behaviour of two SLS materials: LaserForm and DirectSteel has been investigated using Fretting tests, Pin-on-disc tests and microfretting tests. Wear test conditions were determined by calculating Hertzian pressure for various loading conditions, and wear tests were performed under both plastic and elastic contact conditions. Wear analysis was subsequently done to find out the wear resistance of materials. The wear volumes are presented against applied loads and dissipated energies. It has been found out that LaserForm is better than DirectSteel and there is no clear relation between hardness and wear resistance of materials.

null

['Ingenthron, C.', 'Ludwig, H.', 'Joel, T.', 'Agarwal, K.', 'Sealy, W.']

2021-10-20T22:06:05Z

2015

Mechanical Engineering

null

https://hdl.handle.net/2152/89374

eng

2015 International Solid Freeform Fabrication Symposium

Open

['additive manufacturing', 'binder jetting', 'wear behavior', 'stainless steel-bronze', 'metal composites']

Wear Studies in Binder Jet Additive Manufactured Stainless Steel-Bronze Composite

Conference paper

https://repositories.lib.utexas.edu//bitstreams/c692a71e-52c1-40ed-81b7-249593467e22/download

University of Texas at Austin

Additive Manufactured (AM) components can be used for form, fit or function. If these components have to replace the traditionally manufactured parts, they must be evaluated for their properties. One of the properties that are very important in many cases is the wear of material in service. The aim of this research is to study the wear behavior of additive manufactured components under dry sliding conditions. Small cylindrical disks of stainless steel 420-bronze composite were made by binder jet AM process with layer thicknesses of 50 µm, 100 µm and 200 µm. These disks were subjected to varying wear rates using pin-on-disk test based on ASTM standards. Different sliding distances were used on samples to understand the wear phenomenon. The weight of samples before and after tests was recorded to calculate wear rates. Wear debris and samples after testing were evaluated under a scanning electron microscope (SEM) to reveal changes in microstructure. Testing results are presented in this paper along with a discussion on how the wear occurs in the SS420-Bronze composite. This information can be used for designing the products from this AM process to match the requirements in service.

null

['Schmithüsen, T.', 'Scleifenbaum, Johannes Henrich']

2021-11-30T20:43:08Z

2019

Mechanical Engineering

null

['https://hdl.handle.net/2152/90540', 'http://dx.doi.org/10.26153/tsw/17459']

eng

2019 International Solid Freeform Fabrication Symposium

Open

['support removal', 'wet-chemical ablation', 'metal parts', 'laser powder bed fusion']

Wet-Chemical Support Removal for Additive Manufactured Metal Parts

Conference paper

https://repositories.lib.utexas.edu//bitstreams/3bab729d-7d06-4f27-b01c-5b5fb4a7bbc0/download

University of Texas at Austin

The additive manufacturing technology laser powder bed fusion (LPBF) offers great flexibility regarding the manufacturing of complex component structures. Due to the process, support structures have to be manufactured for overhanging component surfaces in order to guarantee dimensional accuracy and reduce distortion. However, these must be removed after manufacturing. Especially for internally supported component surfaces, removal is only possible by means of tool-free technologies. A promising approach for a tool-free support removal is the wet-chemical ablation, in which the support structures are removed by chemical dissolution. So far, the approach has been tested for a few materials (e.g. stainless steel). In order to extend the use of this automatable approach to further AM materials, the influence of different etching agents on different additive aluminium alloys with regard to material ablation and surface influence will be investigated. Finally, the applicability of the results to a supported component will be tested.

null

['Weflen, E.D.', 'Frank, M.C.', 'Peters, F.E.']

2024-03-26T23:30:34Z

2023

Mechanical Engineering

null

['https://hdl.handle.net/2152/124453', 'https://doi.org/10.26153/tsw/51061']

en_US

2023 International Solid Freeform Fabrication Symposium

Open

['metalcasting', 'WAAM', 'wire arc DED', 'human factors']

WIRE ARC ADDITIVE MANUFACTURING IN STEEL FOUNDRIES

Conference paper

https://repositories.lib.utexas.edu//bitstreams/80e5dec7-8a5c-4d5d-a860-a1e7b0d40bf2/download

University of Texas at Austin

This work presents the system design of a robotic hybrid additive and subtractive manufacturing system for steel foundries to reduce supply chain disruptions caused by a skilled labor shortage and harsh working conditions. Automation promises to ease the labor shortage but falls short in environments with high variation and ambiguous decision-making. These challenges were overcome by leveraging human adaptability and uncertainty in decision-making, paired with automation conducting repetitive tasks in harsh environments. Documenting the existing process revealed the current welding approach for removing and refilling metalcasting production anomalies. Tasks were divided into those suited for automation and those best suited for a human operator. The operator continues to identify and remove anomalies while sensing and robotics automate weld preparation by machining, refilling using Wire Arc Additive Manufacturing (WAAM), and surface blending by grinding. This research serves as a case study for integrating hybrid manufacturing into production environments.

null

['Weflen, E.D.', 'Black, M.A.', 'Frank, M.C.', 'Peters, F.E.']

2021-12-01T21:52:28Z

2021

Mechanical Engineering

null

['https://hdl.handle.net/2152/90627', 'http://dx.doi.org/10.26153/tsw/17546']

eng

2021 International Solid Freeform Fabrication Symposium

Open

['wire arc additive manufacturing', 'WAAM', 'low carbon steel', 'casting']

Wire Arc Additive Manufacturing of Low Carbon Steel for Casting Applications

Conference paper

https://repositories.lib.utexas.edu//bitstreams/d5a5f91b-984a-44a5-9647-c20f427008d9/download

University of Texas at Austin

While metal AM research often focuses on high-cost materials, lower-cost alloys such as low carbon steel are used at higher volumes in the casting industry. Welding is a standard process step in casting production, but robotic automation has been limited due to this industry’s low-volume and high-mix. However, advances in flexible automation show their potential. This research presents the application of WAAM using a 6-axis robot with low carbon steel castings. Process parameters, including travel speed, cooling time, and step over distance are evaluated for their effect on the resulting geometry. Demonstration parts assess the ability to produce objects with varying geometries without defects. A method is discussed for depositing material on non-planar surfaces, such as the filling of a concave feature. These findings broaden the scope of applications in which wire arc additive manufacturing can be applied in industrial applications and develops parameters for depositing within non-planar cavities.

null

['Atkins, Celeste', 'Heineman, Jesse', 'Chesser, Phillip', 'Roschli, Alex', 'Post, Brian', 'Lloyd, Peter', 'Love, Lonnie', 'Lind, Randall']

2021-11-18T18:30:29Z

2019

Mechanical Engineering

null

['https://hdl.handle.net/2152/90458', 'http://dx.doi.org/10.26153/tsw/17379']

eng

2019 International Solid Freeform Fabrication Symposium

Open

['wire co-extrusion', 'big area additive manufacturing', 'BAAM', 'Oak Ridge National Laboratory']

Wire Co-Extrusion with Big Area Additive Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/1c6792a1-d028-49f0-b2fe-19b991ca78cb/download

University of Texas at Austin

Oak Ridge National Laboratory’s Manufacturing Demonstration Facility is developing a system that will deposit and embed conductive and resistive elements within a printed bead of material. The system was implemented on a Big Area Additive Manufacturing (BAAM) system using a co-extruding nozzle. It has already been demonstrated that BAAM is useful for the tooling industry, but this could be a great improvement on an established application of BAAM parts. This system will provide the ability to control and monitor the surface of additively manufactured (AM) parts. It will also enable self-heating surfaces of AM parts, which is particularly useful in tooling applications. This system could even be used in the future for embedding other materials not found in pellet form in BAAM parts. This work will cover the development of the co-extrusion system and its integration with the dual-port nozzle and the BAAM system.

null

['Gu, Jianglong', 'Cong, Baoqiang', 'Ding, Jialuo', 'Williams, Stewart W.', 'Zhai, Yuchun']

2021-10-12T22:56:41Z

2014

Mechanical Engineering

null

['https://hdl.handle.net/2152/88764', 'http://dx.doi.org/10.26153/tsw/15698']

null

2014 International Solid Freeform Fabrication Symposium

Open

['Wire+Arc Additive Manufacturing (WAAM)', 'Cold Metal Transfer (CMT)', 'aluminum', 'porosity', 'microstructure', 'mechanical property']

Wire+Arc Additive Manufacturing of Aluminum

Conference paper

https://repositories.lib.utexas.edu//bitstreams/d86ed1d8-41ed-49d1-aafa-a20e4f114e59/download

University of Texas at Austin

Wire+Arc Additive Manufacturing is very suitable for the production of large scale aluminium parts. However implementation is currently limited by issues such as porosity and low mechanical properties. We have studied the utilization of new deposition processes such as pulsed advanced cold metal transfer which allows modification of the thermal profile resulting in refined equiaxed microstructure and elimination of porosity. Standard and new feedstock compositions are being evaluated and developed with ultimate tensile strengths of up to 260 MPa with 17% elongation being obtained in the as-deposited condition. Post build heat treatments compositional changes and high-pressure inter-pass rolling are being investigated in order to increase the strength further.

null

['Reichenbach, Alexandar', 'Silwal, Bishal']

2023-01-27T17:52:43Z

2022

Mechanical Engineering

null

['https://hdl.handle.net/2152/117348', 'http://dx.doi.org/10.26153/tsw/44229']

eng

2022 International Solid Freeform Fabrication Symposium

Open

['Additive manufacturing', 'wire-fed AM', 'RAFM steel']

Wire-Arc Additive Manufacturing of Reduced Activation Ferritic Martensitic (RAFM) Steel

Conference paper

https://repositories.lib.utexas.edu//bitstreams/8d41d1e7-5337-4fdb-8bdb-1741047ec06a/download

null

RAFM steel has been considered as the candidate material for an in-vessel component of the fusion wall reactor. Known as F82H in Japan and Eurofer-97 in Europe, RAFM steel is not commercially available. The goal of this research project is to fabricate and study the technical feasibility of producing RAFM steel welding wire with wire arc AM. Metal-cored wire is a tubular electrode comprised of an outer metal sheath with alloying powdered materials inside the core. Applications of such wire include but not limited to welding, thermal spray, cladding and additive manufacturing (AM). The advantage of using the metal-cored wire is that a higher deposition rate, higher side-wall fusion, can be achieved, and more important, special alloys for special applications can be manufactured at relatively lower cost. A preliminary investigation of wire arc AM of RAFM steel was carried out using Ar-CO2 (c-25) gas. A design of experiments with GMAW based power source waveform using the metal cored wire was conducted to study the printability. The microstructure and mechanical properties (hardness and toughness) was tested, and the data were analyzed and compared with the literature.

null

['Fowler, J.', 'Nycz, A.', 'Noakes, M.', 'Masuo, C.', 'Vaughan, D.']

2021-11-18T00:49:49Z

2019

Mechanical Engineering

null

['https://hdl.handle.net/2152/90378', 'http://dx.doi.org/10.26153/tsw/17299']

eng

2019 International Solid Freeform Fabrication Symposium

Open

['Invar', 'wire-arc additive manufacturing', 'metal big area additive manufacturing', 'MBAAM', 'Oak Ridge National Laboratory']

Wire-Arc Additive Manufacturing: Invar Deposition Characterization

Conference paper

https://repositories.lib.utexas.edu//bitstreams/0d3320e9-0fd1-4690-99e3-7699a231b434/download

University of Texas at Austin

This paper explains and analyzes an investigation into the characteristics of Invar, a Nickel-Iron alloy, with regards to deposition through Wire-Arc Additive Manufacturing performed by the Metal Big Area Additive Manufacturing (MBAAM) team at Oak Ridge National Laboratory’s Manufacturing Demonstration Facility (MDF). The Invar alloy is extremely valuable to multiple fields because of its thermal expansion properties. These fields will attain financial benefits when turning to additive manufacturing as the future production technique for their Invar parts. As such, it will be necessary for AM research to become accustomed with the characteristics of Invar deposition. One of the potential AM techniques that has the potential to carry out printing with this material is Wire-Arc AM. The goal of this paper is to narrow down and call out different welding parameters that optimize the characteristics of Invar deposition using the Wire-Arc AM technique.

null

['Padathu, Ajay Panackal', 'Sparks, Todd', 'Liou, Frank']

2020-02-24T15:06:33Z

2005

Mechanical Engineering

null

['https://hdl.handle.net/2152/80078', 'http://dx.doi.org/10.26153/tsw/7099']

eng

2005 International Solid Freeform Fabrication Symposium

Open

Laser Aided Manufacturing Process

Workpiece Alignment for Hybrid Laser Aided Part Repair Process

Conference paper

https://repositories.lib.utexas.edu//bitstreams/df34f4bd-3111-4168-88d2-f6653d8ec685/download

null

Work piece alignment is a key issue for hybrid laser aided part repair, a process utilizing both machining and laser deposition. Proper alignment can greatly improve the accuracy of the repair process. This paper introduces a method for aligning a physical work piece and a CAD model using a Renishaw touch probe and software tools. Also discussed is a model for computing 5-axis CNC positions based on a desired work piece orientation.

null

Austin F., Aubin

2018-09-27T19:44:33Z

1994

Mechanical Engineering

doi:10.15781/T2G737P38

http://hdl.handle.net/2152/68607

eng

1994 International Solid Freeform Fabrication Symposium

Open

['intelligent manufacturing systems', 'Rapid product development', '3D Printing']

A World Wide Assessment of Rapid Prototyping Technologies

Conference paper

https://repositories.lib.utexas.edu//bitstreams/13471ba2-c96e-4886-896c-94a8ca6e18c0/download

null

This paper describes the results of a worldwide assessment of comnlercial rapid prototyping technologies that was initiated in the Intelligent Manufacturing Systems IMS Test Case on Rapid Product Development. Additionally, this paper will highlight the development of university-led rapid prototyping technologies.

null

['Sellers, R.', 'McCullough, C.', 'Gonzalez, E.', 'Light, A.', 'Wolff, S.', 'Wang, H.']

2023-04-05T13:55:15Z

2022

Mechanical Engineering

null

['https://hdl.handle.net/2152/117776', 'http://dx.doi.org/10.26153/tsw/44655']

eng

2022 International Solid Freeform Fabrication Symposium

Open

['Additive manufacturing', 'Ti64', 'SS 316L', 'Laser Powder Bed Fusion', 'X-ray Analysis', 'Keyhole', 'Marangoni Flow', 'Magnetic Fields']

X-Ray Analysis of Magnetically Induced Additive Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/d06b32ff-a77c-43bc-b836-7d2330dc4be7/download

null

Through advancements in technology over the last several years, additive manufacturing has become increasingly mainstream in the manufacturing process. Additive manufacturing has several traits which would theoretically make it superior to traditional subtractive manufacturing techniques. While this ability to manufacture complex parts is certainly applicable to the external structure, additive manufacturing will allow for control over the internal structure of a part as well. From this, porous components can be created which match desired mechanical properties somewhat independently of the material actually used for manufacturing. However, many of these advancements require further refinement of the additive manufacturing processes intrinsic to them. One of the techniques suggested as a method of improving additive manufacturing processes is the incorporation of magnets into the manufacturing process. These magnets are used to direct the flow of the melted metal with more precision. Experiments were conducted in order to evaluate the effects of the introduction of magnets on parts printed using Laser Powder Bed Fusion. Stainless steel 316L, a relatively cheap and easy to print steel, was printed onto a Ti64 substrate using both spot welding and line scanning. It was observed that magnets had an effect on the melt pool and the keyhole depth through an analysis of the spot welding. Additionally, the various magnets also changed the flow of particles in the melted areas generated through line scanning. While quantifying the magnetic fields' effects will require additional research and time, there is strong evidence that they could be a viable solution to increasing additive manufacturing’s precision.

null

['Lau, Wing', 'Bradbury, Tom', 'Youssef, Adolphe', 'Gaylo, Chris', 'Sun, Wei', 'Lau, Alan']

2019-10-23T15:07:30Z

2002

Mechanical Engineering

null

['https://hdl.handle.net/2152/76754', 'http://dx.doi.org/10.26153/tsw/3843']

eng

2002 International Solid Freeform Fabrication Symposium

Open

Heterogeneous

XML Representation and Process Algorithm for Layered Manufacturing of Heterogeneous Objects

Conference paper

https://repositories.lib.utexas.edu//bitstreams/47aba2f1-b397-4876-9d1d-577005e631b4/download

null

In the fast developing technology of solid freeform fabrication, it remains a challenge to fabricate a heterogeneous object by layered manufacturing because conventional CAD systems and STL databases do not contain material and manufacturing information. This paper presents a novel approach to layered manufacturing of heterogeneous objects. A new processing algorithm based on the Extensible Markup Language (XML) format is being developed to process heterogeneous objects for layered manufacturing. The model database containing geometry, topology, material and manufacturing information is described by XML structural elements with the hierarchy analogized to the TREE data structure of the Boundary Representation (B-Rep) and/or the Constructive Solid Geometry (CSG) model. A process model for layered manufacturing is formulated based on the XML format for the fabrication of heterogeneous objects. A case study is presented to demonstrate the process algorithm for representing a multimaterial B-Rep model in the context of Three Dimensional Printing (3DP) technology. Specifically, the case study will show the conversion of a solid model to XML representation, the material assignment, the slicing, and the machine toolpath generation. The paper also presents a brief survey of technological application of XML and associated technologies.

null

['Weber, Daniel H', 'Zhou, Wenchao', 'Sha, Zhenghui']

2023-01-26T14:43:20Z

2022

Mechanical Engineering

null

['https://hdl.handle.net/2152/117309', 'http://dx.doi.org/10.26153/tsw/44190']

eng

2022 International Solid Freeform Fabrication Symposium

Open

['Cooperative 3D Printing', 'Swarm Manufacturing', 'Geometric Partitioning']

Z-Chunking for Cooperative 3D Printing of Large and Tall Objects

Conference paper

https://repositories.lib.utexas.edu//bitstreams/8627e73e-2a3f-4e84-993a-dc9e2123638e/download

null

Cooperative 3D Printing (C3DP) is an emerging technology designed to address the size and printing speed limitations of conventional gantry-based 3D printers. To print large-scale objects, C3DP divides a job into chunks to be printed by a swarm of mobile robots. Previously, we developed a Chunker algorithm to partition jobs into printable parts in the XY direction, which theoretically enables the printing of objects of unlimited size in XY dimensions. However, print size is limited in the Z direction due to the physical constraints of the printer. In this paper, we introduce the first working strategy and rules of Z-Chunking for C3DP, such as where and how to place chunk boundaries along the Z direction and alignment geometries for easy post-assembly. Additional challenges of interfacing with XY chunking and facilitating re-assembly of the job are also considered. We conduct two case studies on objects of varying geometric complexity (e.g., simple solids vs. hollow structures) in which the object is chunked, printed, and assembled.

null

['Duty, Chad', 'Failla, Jordan', 'Kim, Seokpum', 'Smith, Tyler', 'Lindahl, John', 'Roschli, Alex', 'Post, Brian', 'Love, Lonnie', 'Kunc, Vlastimil']

2021-11-16T15:24:17Z

2018

Mechanical Engineering

null

['https://hdl.handle.net/2152/90312', 'http://dx.doi.org/10.26153/tsw/17233']

eng

2018 International Solid Freeform Fabrication Symposium

Open

['z-pinning', 'mechanical anisotropy', '3D printed parts', '3D printing']

Z-Pinning Approach for Reducing Mechanical Anisotropy of 3D Printed Parts

Conference paper

https://repositories.lib.utexas.edu//bitstreams/e1b2ea0e-60b8-4f31-bd70-3eace978ba21/download

University of Texas at Austin

The mechanical strength of extrusion-based printed parts is often greatly reduced (25-50%) in the build direction (z-direction) compared to the in-plane strength due to poor bonding between successively deposited layers. This effect can be magnified (75-90% difference) when depositing fiber-reinforced materials or larger print areas with long layer times. Therefore, a patent-pending approach has been developed that deposits material into intentionally aligned voids in the z-direction, allowing continuous material to span multiple layers. The “z-pinning” approach can be applied to several concepts for improving the interlaminar strength of extrusion-based 3D printed parts as well as techniques for applying the technology across a broad spectrum of deposition platforms and material systems. Initial experimental results demonstrate a significant improvement (>3x) in mechanical strength and (>8x) toughness for fiber reinforced components.

null

['Stucker, Brent', 'Bradley, Walter', 'Eubank, P.T.', 'Norasetthekul, Somchintana', 'Bozkurt, Bedri']

2018-11-30T15:22:52Z

1997

Mechanical Engineering

doi:10.15781/T2ZW19C36

http://hdl.handle.net/2152/70593

eng

1997 International Solid Freeform Fabrication Symposium

Open

['EDM', 'ZrB2 powders']

Zirconium Diboride/Copper EDM Electrodes From Selective Laser Sintering

Conference paper

https://repositories.lib.utexas.edu//bitstreams/6118fdcf-a80d-4285-a290-6f8909035383/download

null

Bibas, C.

2021-12-07T18:08:50Z

2021

Mechanical Engineering

null

['https://hdl.handle.net/2152/90742', 'http://dx.doi.org/10.26153/tsw/17661']

eng

2021 International Solid Freeform Fabrication Symposium

Open

['Øgon', 'lens free optical scanner', 'LFOS', 'additive manufacturing']

Øgon, A Revolutionary New Lens Free Optical Scanner (LFOS) for Additive Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/ac81482a-5b8e-4e2f-bbd8-6e01043f0805/download

University of Texas at Austin

null

This paper describes the optics of the Øgon™ and compares it head to head with the GS.

null