Closed-loop control of meltpool temperature in directed energy deposition

Materials & Design

Benjamin D. Bevans¹  Brent Roeder²  Jeffrey E. Shield³  Aniruddha Gaikwad⁴  James Craig⁴  Ziyad Smoqi⁴  Prahalada Rao⁴  Bill Macy⁵  Alan Abul-Haj⁶ 

[1] Corresponding author.;ARA Engineering, Sedona, AZ, United States;Macy Consulting, St. Louis, MO, United States;Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE, United States;R3 Digital Sciences, Blacksburg, VA, United States;Stratonics, Inc., Lake Forest, CA, United States;

关键词: Directed energy deposition;    Closed-loop control;    Meltpool temperature;    Dual-wavelength pyrometer;    Microstructure;    Porosity;   

DOI  :  

来源: DOAJ

【 摘 要 】

The objective of this work is to mitigate flaw formation in powder and laser-based directed energy deposition (DED) additive manufacturing process through close-loop control of the meltpool temperature. In this work, the meltpool temperature was controlled by modulating the laser power based on feedback signals from a coaxial two-wavelength imaging pyrometer. The utility of closed-loop control in DED is demonstrated in the context of practically inspired trapezoid-shaped stainlesssteel parts (SS 316L). We demonstrate that parts built under closed-loop control have reduced variation in porosity and uniform microstructure compared to parts built under open-loop conditions. For example, post-process characterization showed that closed-loop processed parts had a volume percent porosity ranging from 0.036% to 0.043%. In comparison, open-loop processed parts had a larger variation in volume percent porosity ranging from 0.032% to 0.068%. Further, parts built with closed-loop processing depicted consistent dendritic microstructure. By contrast, parts built with open-loop processing showed microstructure heterogeneity with the presence of both dendritic and planar grains, which in turn translated to large variation in microhardness.

【 授权许可】

Unknown