Numerical and experimental investigation of effective parameters on separation force in bottom-up stereolithography process

Bottom-up stereolithography is included among the additive manufacturing methods, which gives many advantages over top-down stereolithography. The major advantages are related to better fabrication resolution, higher material feed-rate, shorter production time and less material waste. During this process, a separation force is generated as a solidified layer separates from the base of resin container. This force leads to product delamination which in turn stimulates the product failure. An efficient solution to this problem is achieved by studying the interaction force on the specimen contact zone. The approach proposed in this study is based on experimental measurements of the force exerted during the process. Different parameters regarding process characteristics are varied in several tests and a comprehensive analysis is conducted to correspond test condition to the resulting separation force. The significant parameters are process speed, cross-section area, the complexity of geometry and orientation of solidification. For some different cases, the separation force varies between 3 and 36N, and the highest difference between the simulated and experimental results remains beyond 5%. It is observed that higher velocity, larger cross-section area or more part geometry complexity increase the separation force. Another novelty concerns the study of the producing orientation on the separation force. Related experimentation is performed to determine the effect of cross-sectional and geometrical complexity. This article finally gives some preliminary propositions for the part design.