The Influence of Support Roughness on Shape Distortion of Binder-Jetted Parts During Sintering—Experimental and Modelling Analysis

In recent years, metal binder jetting (MBJ) has seen increasing adoption in diverse manufacturing sectors due to its scalability, design flexibility, and high cost-efficiency. Sintering the green part at high temperature is an essential step to obtain a nominal product; nonetheless, it may detrimentally affect dimensional and geometrical accuracy, as parts with complex geometries undergo shape distortion because of gravity and/or friction at the contact area with the sintering trays. This study aimed to investigate the friction-induced deformation of sintering stainless-steel 316L thin-walled cubes on alumina supports with different surface finishing; arithmetic average roughness (Ra) and Maximum Height of the Profile (Rz) ranged from 0.2 to 12 μm and 3 to 60 μm, respectively. The deviation in the sintered cubes, measured using a Coordinate Measuring Machine (CMM), did not show a clear pattern as a function of surface finishing. Finite Element Modelling (FEM) confirmed that shape distortion during sintering marginally increases with an increase in the friction coefficient. Assuming a heterogeneous initial density distribution, the simulation results showed good agreement in predicting the concave deformation patterns observed in many samples (~0.45 mm, less than 5% error along the y-direction). This work proposes novel insight into the influence of tray roughness and the combined effect of friction and density distribution on shape distortion during sintering.