Influence of Mechanical Anisotropies on the Machinability of an Additively Manufactured Stainless Steel (1.4404)

Abstract

Additive manufacturing methods like Laser Powder Bed Fusion (L-PBF) offer great geometrical design flexibility. Until now, L-PBF manufactured parts need post-process operations like machining to meet the demands of surface quality and dimensional accuracy of most applications. Due to the layer-by-layer methodology during the building process, mechanical anisotropies can develop in the part. These can have a significant effect on the chip formation depending on the direction of material removal. The aim of this work is to contribute to the understanding of the influence of anisotropies on the machinability of stainless-steel samples (material no.: 1.4404) manufactured by L-PBF. Using linear-orthogonal cutting tests, fundamentals of the chip formation are observed in dependence of L-PBF-parts manufactured with different process parameters. Variations include layer thickness and part orientation during the L-PBF process. Especially the part orientation is of great importance as it has a significant impact on the mechanical anisotropy. The experiments were carried out at different cutting conditions. To understand the results, focus is mainly given to the cutting and feed forces as well as the chip thickness values. The experimental results are supplemented with analytical analyses to understand the influence of part orientation and layer thickness in more detail.