Research on support-free WAAM based on surface/interior separation and surface segmentation

摘要

Metal additive manufacturing has been widely used in many fields. It is important to realize the support-free deposition of metal parts since the supporting structure is hard to remove. Some of the existing support-free methods are complicated by generating curved layers, which may also cause defects between layers. This paper presents a support-free wire and arc additive manufacturing (WAAM) method based on surface/interior separation and surface segmentation. A metal part model is first divided into the surface and interior solid (IS), and the surface is segmented further into the overhanging area (OA) and the nonoverhanging area (NOA). The OA is deposited with multiaxis motion of a robot to avoid the overhanging phenomenon. The NOA and IS are deposited vertically in the traditional way. Path planning is performed by alternatively depositing the OA and the NOA and IS. To reduce the number of voids between layers, an IS filling method is proposed in which the adjacent layers are filled with interlaced passes. The density of the part with interlaced passes increases by 1.9 % compared with the part with noninterlaced passes. Two typical models are deposited without any support to verify the feasibility of the proposed methods.