A novel method to improve the removability of cone support structures in selective laser melting of 316L stainless steel

Abstract

In selective laser melting (SLM), support structures play a critical role in successful printing. Despite its necessity, the removal of support structures after printing becomes a challenging task which is usually time-consuming and labour-intensive. Mechanical post-processing can be employed to facilitate the automatic removal of support structures with higher efficiency. However, the mechanical forces of a machining process such as milling can cause the cone supports to tilt, collapse and be pulled up. This paper presents a novel method to improve the machinability of cone support structures. In this method, the epoxy resin is filled into the gaps between the entire cone support structures to form a solid composite structure after the epoxy resin is fully cured. The relationship between the force components in various directions during support removal is theoretically analyzed. The method is studied in terms of cutting performance, cutting force and energy, tool wear, workpiece surface damage and corrosion behaviour. On top of rectifying the problems of resultant support tilting and collapsing, the cutting force, specific cutting energy, tool wear and damage to the workpiece surface are significantly reduced, and the corrosion behaviour of the samples is slightly improved due to better surface quality after support removal. A finite element model is constructed for analysis of the underlying mechanisms. This paper addresses the research gap on the corrosion behaviour of the workpiece after support removal, and the newly developed method can be further applied to the machining of other types of support structures in SLM.