Precision milling of high volume fraction SiCp/Al composites with monocrystalline diamond end mill

Silicon carbide particle-reinforced aluminum matrix (SiCp/Al) composites have attracted considerable interest as potential materials due to their excellent engineering properties. Many research works have been done associated with turning SiCp/Al in the past. However, it still lacks of experience on milling of SiCp/Al composites. This paper presents an exploratory study on precision milling of SiCp/Al composites with higher volume fraction (SiCp, 65 %) and larger particle size. The experiments were conducted on a Kern MMP 2522, high-precision micromilling machine center. A single flute monocrystalline diamond end mill was used to mill straight grooves with cutting parameters in a few micros. The machined surface quality including surface roughness and surface topography were studied. The cutting mechanisms of SiC particle and tool wear characters were also investigated. The results showed that mirror-like surface with surface roughness around 0.1 mu m Ra can be achieved by precision milling with small parameters in the range of a few micros. Most of the SiC reinforcements were cut in partial ductile way with microfractures and cracks on the machined surface; tool wear included chipping and cleavage on monocrystalline diamond edge. A large flank wear on tool bottom face was observed and suspected to be caused by coaction of chemical transition and mechanical abrasion.