An approach to partition workpiece CAD model towards 5-axis support-free 3D printing

Abstract

This paper presents a new method to fabricate workpieces using a 5-axis printing equipment with similar movement way of 5-axis milling machine tools. The method includes two main steps: (i) CAD model is partitioned into several sub-parts using a gravity effect partition method simulating the material-falling process when the model is stacked along the Z direction. In our processing plan, every sub-part has a slice direction. Before printing a sub-part, we rotate A axis and C axis so that its slice direction exactly coincides with the Z axis positive direction and then materials are stacked along the slice direction; (ii) these sub-parts are sorted with printing-base constraint and interference-free constraint. The two constraints, respectively, mean that the previously printed sub-parts are used as the printing bases of subsequently printed sub-parts; there is no interference between printed sub-parts and the printer head. These partition and sort principles have been generalized as an optimization model to satisfy printing-base constraint, interference-free constraint, and shortest empty printing path constraint. Our printing processing-plan can be regarded as a process to solve the optimization model. We have successfully generated sub-part sequences for some CAD models with large overhangs and complex structures to verify the printing processing-plan method.