Browsing by Subject "in-situ process monitoring"
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Item Development of a Standalone In-Situ Monitoring System for Defect Detection in the Direct Metal Laser Sintering Process(University of Texas at Austin, 2019) Quinn, Paul; O'Halloran, Sinead; Ryan, Catriona; Pamell, Andrew; Lawlor, Jim; Raghavendra, RameshDirect metal laser sintering (DMLS) is a powder bed fusion (PBF) additive manufacturing process commonly used within the medical device and aerospace industries where regulations drive the requirement for stringent quality control. Using in-situ monitoring, the identification of defects, as well as the geometric and dimensional measurement of the layers throughout the build allows for greater quality control, as well as a reduction in the requirement for ex-situ measurement. A standalone monitoring system for the EOS M280 is presented in this research, allowing for the build process to be monitored layer-by-layer. The system images the build area after powder deposition and after laser exposure allowing for the identification of inefficiencies in both the powder deposition and the laser exposure. The system has proven to be capable to identify in build defects and work is ongoing to develop an automated program to identify these defects and notify the operator in real time.Item In-Situ Process Monitoring and Ex-Situ Part Quality Assessment of Selective Laser Sintering Using Optical Coherence Tomography(University of Texas at Austin, 2016) Lewis, Adam; Gardner, Michael; McElroy, Austin; Milner, Thomas; Fish, Scott; Beaman, JosephWidespread commercial adoption of Selective Laser Sintering has been hindered by inadequate quality and consistency of manufactured parts. Improved process monitoring and control have the potential to improve part quality and thus increase adoption of SLS for various applications. In this paper, optical coherence tomography (OCT) is explored as a new process monitoring tool in SLS polymer printing. The basic operating principles behind OCT are reviewed to illustrate the potential monitoring capabilities followed by results for both in-situ process monitoring and ex-situ examinations of built parts comprised of various polymers. Capabilities and limitations of OCT in each application are discussed.Item An Integrated Approach to Cyber-Enabled Additive Manufacturing using Physics based, Coupled Multi-scale Process Modeling(University of Texas at Austin, 2012) Pal, Deepankar; Patil, Nachiket; Nikoukar, Mohammad; Zeng, Kai; Haludeen Kutty, Khalid; Stucker, Brent E.The complexity of localized and dynamic boundary conditions in additive manufacturing processes makes it difficult to track in-situ thermo-mechanical changes at different length scales within a part using experimental equipment such as a FLIR1 system and other NDE2 techniques. Moreover, in-situ process monitoring is limited to providing information at an exposed surface of the build. As a result, an understanding of the bulk microstructure and behavior of a part still requires rigorous post-process microscopy and mechanical testing. In order to circumvent the limited feedback obtained from in-situ experiments and to better understand material response, a novel 3D dislocation density based thermo-mechanical finite element framework has been developed. This framework solves for the in-situ response 2 orders of magnitude faster than currently used state-of-the-art modeling software since it has been specifically designed for additive manufacturing platforms. Various aspects of this simulation tool have been and are being validated using research grants from NSF3, ONR4, AFRL5, NIST6 and NAMII7. This modeling activity has many potential commercial impacts, such as to predict the anisotropic performance of AM-produced components before they are built and as a method to enable in-situ closed-loop process control by monitoring the process and comparing it to predicted responses in real time (as the model will be used to predict results faster than an AM machine can build a part). This manuscript provides an overview of various software modules essential for creation of a robust and reliable AM software suite to address future needs for machine development, material (alloy) development and geometric optimization.Item Investigating the Relationship Between In-Process Quality Metrics and Mechanical Response in the L-PBF Process(2022) Sampson, Bradley J.; Morgan-Barnes, Courtney; Stokes, Ryan; Doude, Haley; Priddy, Matthew W.Laser powder bed fusion (L-PBF) additive manufacturing is a process that utilizes a high- powered laser to build near net-shaped parts in a layer-by-layer fashion using metal powder as the feedstock material. Traditionally, the analysis of L-PBF produced parts has relied solely on post- build characterization to understand the relationship between the printing process and the final mechanical properties. Recent developments of in-process quality assurance systems, such as Sigma Additive Solutions’ PrintRite3D, can measure in-process thermal signatures and melt pool disturbances in real-time. This research aims to examine the relationship between process parameters (e.g., scan strategy, scanning speed, and layer thickness) and in-process quality metrics (IPQMs) captured by the PrintRite3D system on a Renishaw AM400. The mechanical response of multiple part geometries (NIST residual stress bridges, single-arched bridges) and build materials (Ti6Al4V) includes residual stress deflection and hardness; the results are compared with the IPQMs.