Characterization of the Surface Error During Peripheral Milling of Thin-Walled, Near-Net-Shaped Structures

Lightweight aerospace structural components are usually milled out of plate-material, converting up to 95% of the material into difficult to recycle chips. Therefore, additive-manufacturing holds great resource saving potential through the near-net-shape production of thin-walled parts. However, these parts pose new challenges. For example, previous methods such as the “waterline”-path approach, which uses the residual stiffness of the solid-block to reduce the deformation of the thin-walls due to process forces, can only be applied to a very limited extent. This results in a greater deflection of the near-net-shape, additively-manufactured structure. In this paper the surface error is investigated using milling experiments. An analytical approach to qualitatively predict the surface characteristics is provided. The results get used to discuss whether an adjustment to the tool path is suitable to compensate for the dimensional error. Such a compensation method has the potential to efficiently machine near-net-shape semi-finished parts within the required tolerances.