A path planning method for robotic Additive Manufacturing

Abstract

In the last decades, the field of Additive Manufacturing (AM) has seen an increase of industrial robots, used in substitution to the conventional 3-axis CNC Cartesian robots, to overcome drawbacks such as staircase effect (quality of the finished hull), the need for support structure in case of overhanging features (creation of scraps) and the possibility to generate only small and medium size components. This article addresses the steps required to transfer a G-code intended for a CNC machine to an industrial robot, limiting the effects on the final build. The focus is put on those machines that do not allow the programmer to define the trajectory at each cycle time, leading to a non negligible differences between the intended and the yielded part. To achieve the suitable acceleration-deceleration profile, the G-code undergoes a post-processing routine redefining the toolpath by using the primitives already implemented in the controller (i.e. lines and circles) instead of just linear movements. Experiments have been carried out on an Epson T3 SCARA, mounting an FDM (Fused Deposition Modeling) extruder directly instructed by the robot according to the actual Tool Center Point (TCP) speed.