Investigation on anisotropic behavior of additively manufactured maraging steel during orthogonal cutting

Abstract

Laser powder bed fusion (LPBF) as an additive manufacturing (AM) process allows for sophisticated geometries to be produced. With optimized process parameters high densities of the metal parts can be achieved. The locally concentrated melting and fast solidification leads to a fine dendritic microstructure depending on the melt pool size. In this dendritic structure the layer wise build-up is still visible. It is well known that this leads to an anisotropic material behavior.In this paper the influence of the build-up orientation relative to the cutting vector on the cutting process is studied. For this objective, specimens out of maraging steel with different build-up directions are build and subsequently examined utilizing an orthogonal cut. During the cut, forces, vibrations and acoustic emission are used to investigate the cutting behavior. Furthermore, the chips are analyzed for the geometric characteristic values. With this, the anisotropic behavior could be demonstrated. Depending on the build-up orientation α, cutting force varies by up to 6 % and thrust force by up to 8. Chip thickness also varies depending on α by up to 18,6 %. Based on the findings, a regression model is developed which maps the specific material properties. This makes it possible to predict resulting cutting forces and chip volume, based on the layer penetration angle. Finally, this leads to a better understanding of the interactions between the additive subtractive process chain.