Effects of powder loadings on the green-state micromachinability of additive manufactured AISI316L

In Additive Manufacturing based on metallic feedstock extrusion, the powder loading strongly affects the feedstock extrudability and sinterability. The adoption of intermediate micromachining steps after the 3D part deposition allows the implementation of the so-called hybrid production, that provides the capacity to efficiently obtain tiny and accurate features on almost every material. This study investigates the effect of particle loading on the micromachinability of additive manufactured AISI316L feedstock. Feedstock with particles of 15-45 µm (D90 diameter value) was first produced in house with different particle loadings (87.5-90-92.5%) and it was then processed by a prototype 3D printer to produce the parts to micromill. Micromilling of multiple slots with 1x0.5 mm (WxD) were conducted to investigate how the powder loading interacts with the cutting parameters (feed rate and cutting speed) to generate the cutting forces and the geometrical/dimensional quality of the parts.