IFAC IMS 2019 special issue: process planning solution strategies for fabrication of thin-wall domes using directed energy deposition

Abstract

ABSTRACT Although multi-axis bead deposition-based additive manufacturing processes have been investigated in many aspects in the literature, a general process planning approach to address collision detection and prevention still needs to be developed to fabricate complex thin-wall geometries in a supportless fashion. In this research, an algorithm is presented that partitions the surfaces of the part and finds the appropriate tool orientation for each partition to avoid collisions.1 This algorithm is applied to segment the surface of a thin-wall hemisphere dome and fabricate it without the need of support structures. Two main fabrication strategies are developed: wedge-shaped partitioning, and a rotary toolpath. A five-axis toolpath and a 2 + 1 + 1-axis toolpath is introduced to fabricate the partitioned build scenarios. A rotary (1 + 3-axis) toolpath is also developed. Tool paths are developed, and the domes built using a directed energy deposition process. The built geometry aligns well with the process planning solutions, but material build up is observed at the partition interfaces. Planar slicing is used to generate toolpaths. However, it is concluded that planar slicing brings limitations to reduce the number of partitions that can be modified by a constant-step-over toolpath.