An experimental investigation on peripheral milling of magnesium composite AZ91 magnesium matrix with 15 vol.% SiC particles of a nominal 3–4 μm was performed to study the cutting forces generated, surface finish of the machined surface and the tool wear as a function of cutting conditions. The feed force was found to increase with feed and spindle speed, while the thrust forces were found to increase with feed and no significant trend was observed with the increase in spindle speed. The feed and spindle speed were varied from 0.2 to 1 mm/rev and 1000 to 4000 rpm respectively. The length of cut was kept constant at 32 mm.
The tool wear was measured along the helical cutting edge and the wear mechanism was studied through SEM images of the cutting edge. A tapered wear geometry was observed which can be attributed to the varying chip load along the helix. Abrasive wear was identified as the main wear mechanism. Micro-ploughing and micro-pitting were also observed. The extent of micro-ploughing and micro-pitting depended on the cutting condition. When the impact on the cutting edge was high during aggressive machining condition of 0.5 mm/rev and 4000 rpm, extensive micro-pitting and micro-ploughing were observed on the flute. The cutting edges appeared to be smooth due to repeated rubbing against SiC particles and wear debris.