Session: 03-02-02: Advanced Manufacturing

Paper Number: 121479

121479 - Analysis of the Gas Flow Distribution in Laser Powder Bed Fusion Utilizing Particle Image Velocimetry 

Metal additive manufacturing (AM) is being sought for various applications in the aerospace industry. Laser Powder Bed Fusion (LPBF) appears to be leading in this charge due to its ability for manufacturing components with complex geometries and utilizing materials that are difficult to apply subtractive manufacturing techniques. In LPBF, an inert atmosphere is developed inside the build chamber to protect the melt pool from potential contaminants. Furthermore, a constant and uniform flow is desired to remove smoke and condensate. However, spatial variations in the distribution of porosity and mechanical properties of metal from different locations of the build chamber in LPBF suggest that the gas flow distribution may not be sufficient to control metal quality in specific areas of the build chamber. Experimental evaluations of the gas flow distribution reported in the literature are scanty, and complicated by constraints of the build chamber and concerns associated with contamination of the machine. The goal of this presentation is to summarize efforts at the University of Washington to develop an approach for characterizing the inert gas flow in an EOS M290 LPBF printer utilizing Particle Image Velocimetry (PIV) and to share preliminary results. A model of the build chamber was constructed for the EOS M290 to enable experimentation utilizing PIV. The evaluation was conducted utilizing planar views of the flow field in three locations of the build chamber that correspond to regions in which corresponding metal properties have been determined in complementary builds with Ti6Al4V. The flow fields were documented and characterized using LaVision FlowMaster in conjunction with an Evergreen 200 laser. Complimentary analyses were conducted to characterize the velocity distribution, including its magnitude and orientation, as well as areas of turbulent flow. Preliminary results obtained from PIV indicate that there are spatial variations in the gas flow, including locations of turbulence along the powder surface. In addition, regions of nonuniform flow evident in the three planar views distinguished that the planar analysis may not be sufficient to accurately quantify important qualities of the flow characteristics and that further evaluation utilizing stereoscopic PIV will be necessary. Details of the experimental evaluation will be presented as well as quantitative descriptions of the flow field and its importance to maximizing quality of the metal. 

Presenting Author: Aaron Abeyta University of Washington

Presenting Author Biography: Aaron Abeyta is currently a PhD student in the department Materials Science and Engineering at the UW, He has a BS degree in Aeronautics and Astronautics and his current research interests are advanced manufacturing processes.