Analysis of deposition sequence in tool-path optimization for low-cost material extrusion additive manufacturing

This study draws attention to the issue of how sensitive a low-cost 3D printer is to the material deposition sequence, when trying to speed up the process by applying tool-path optimization. The objective was to evaluate the influence of some changes in the deposition sequence on the mechanical properties, dimensional variation, and building time of specimens manufactured in polylactic acid (PLA). To achieve that, three deposition strategies were planned considering different deposition sequences, with and without optimization. An experiment involving an interruption of the extrusion nozzle was also designed to analyze the influence of idle time during material deposition. The material properties were evaluated by tensile and three-point bending tests. The results showed that a longer idle time between adjacent raster segments caused material cool-down, which, in this study, decreased the tensile strength by 35% and the flexural strength by 46%. Therefore, in a low-cost 3D printer, if the user does not pay attention to the deposition sequence during tool-path optimization, the mechanical property of the material can be badly affected. Additionally, the optimized intercalated deposition sequence allowed for savings of up to 42.7% in manufacturing time, and no expressive dimensional variation was found between the deposition strategies.