Micromilling of Metallic Feedstock Produced by Extrusion Additive Manufacturing

Greenstate micromilling is a very promising method that can be integrated in to the 3D printing of metallic micro components using feedstock, for compensating the lack of micro reachability that typical extrusion-based additive manufacturing (AM) method cannot deal with. This integration can aid manufacturing of complex geometries, generation of good surface quality and can provide exceptional flexibility to new product shapes. In this machinability study, the effects of workpiece temperature on green machining is studied, in addition to the micromilling parameters such as cutting speed, feed per tooth, axial depth of cut and air supply for feedstock components produced by extrusion-based AM. Edge integrity and surface roughness of the machined slots are analysed using 3D microscopy and acquired cutting force signals are analysed for each micromilling condition. The micromilling of workpiece at hot temperature (45°C) with an air supply for debris removal showed the best surface quality with least surface roughness value. The micromilling parameters at lower levels seemed to be appropriate for the greenstate micromilling of extrusion additive manufactured parts. This study confirms the possibility of implementing micromilling into extrusionbased 3D printing manufacturing cycles of metallic feedstock.