Dynamic material deposition control for large-scale additive manufacturing

Abstract

Large-scale additive manufacturing involves fabricating parts by joint printing of materials layer upon layer. The product quality and process efficiency are yet to be addressed to guarantee the process viability in practice. The print surface temperature has a significant impact on both of these elements and can be controlled by properly scheduling the material depositions on the surface. The thermal infrared images captured in real-time are processed, and the extracted thermal profiles are translated into a nonlinear profile model describing the heat dissipation on the surface. A real-time layer time control model is formulated to determine the best time to print the next layer. Furthermore, exploiting the maneuverability characteristics of the printer head while considering its mechanical constraints, a real-time printer head speed control model is formulated as a nonlinear mixed-integer program. Following the deterministic finite-state optimal control and shortest path problem paradigm, a novel algorithm is developed to decide the optimal printing speed trajectory for each layer. The proposed approach was tested by two case studies, including a thin wall specimen and a car lower chassis. The results showed that the method can capture the thermodynamics of the process and achieve simultaneous improvement in both quality and efficiency.

Keywords:

• Large-scale additive manufacturing
• print surface temperature
• material deposition flow
• thermal gradient
• thermal image
• layer time control
• printer head speed control

Notes on contributors

Sepehr Fathizadan is pursuing a Ph.D. degree in the Industrial Engineering at Arizona State University in Tempe. He received his MS and BS in Industrial Engineering from Sharif University of Technology and Iran University of Science and Technology in 2016 and 2014 respectively. His main area of expertise includes the integration of optimization, machine learning, and statistics. He is currently working on real-time monitoring and control for additive manufacturing processes.

Feng Ju is an Assistant Professor with the School of Computing, Informatics & Decision Systems Engineering, at Arizona State University, in Tempe, AZ. He received a B.S. degree from Shanghai Jiao Tong University, Shanghai, China, in 2010, and an M.S. degree in electrical and computer engineering and Ph.D. degree in industrial and systems engineering from the University of Wisconsin, Madison,WI, USA, in 2011 and 2015, respectively. His research interests include modeling, analysis, continuous improvement, and optimization of manufacturing systems. He has been a recipient of multiple awards, including the best paper award in IISE Transactions and IFAC MIM, and best student paper award in IEEE CASE.

Feifan Wang received a Bachelor's degree from the Department of Industrial Engineering, Zhejiang University of Technology, Hangzhou, China, and a Master’s degree from the Department of Industrial and Systems Engineering, Zhejiang University, Hangzhou, China, in 2013 and 2016, respectively. Currently, he is working towards a Ph.D. degree at the School of Computing, Informatics, and Decision Systems Engineering, at Arizona State University, Tempe, AZ, USA. His research interests include the modeling, analysis, and control of production systems.

Kyle Rowe earned his Doctorate degree in Mechanical Engineering at the University of Florida in 2015, where he specialized in the field of tribology: the study of friction, wear, and lubrication. His research was varied, spanning the friction and wear of elastomers in combined rolling and sliding to cellular 3D printing. His recent work has focused on large scale polymer extrusion deposition; including molecular dynamics to structural performance of vehicle structures.

Nils Hofmann received his Master of Science in Mechanical Engineering – Manufacturing Technology (Diplom Ingenieur Machinenbau Berufsakademie) from the University of Cooperate Education in Stuttgart, Germany and a Bachelor of Science in Engineering (Mechanical Engineering) from the Open University of London in 2004. He spent 12 years with Mercedes Benz in Stuttgart Germany and now is the Director of Labs and technical Partnerships at Launch Forth by LM Industries Group Inc. in Tempe, Arizona. He currently directs 23 Subject Matter Experts to support the cooperation with and integration of industry and university partners in a variety of projects with advanced manufacturing and new mobility solutions.