Micro milling of pure copper

Unpredictable tool life and premature tool failure are the major concerns in micro machining using micro grain carbide cutters. In this study, the failure mechanism and factors which affect the micro end mill were studied during machining of pure copper workpiece. The machining operation were performed at various cutting speeds, depth of cuts, and feed rates to identify the failure mechanisms using two different helix angles. Chips observed were spiral in shape based on the cutter geometry. The chip size drastically differs from the conventional cutting, but the chip shape remains the same. Both spiral and broken chips were formed. Tool wear increases with the machining time and has a significant effect on the cutting forces. The cutting forces were small compared to conventional cutting. Both feed and radial forces were proportional to the feed rate and depth of cut. Cutting force increases with time as the wear progresses. From this experiment, it is concluded that the helix angle plays an important role. It is also observed that increase in depth of cut increases the tool life, which is quite unique and differs from the mechanics of machining.