Abstract
A ball endmill made of single-crystalline diamond was used for cutting two kinds of mold materials, oxygen-free copper and reaction-bonded silicon carbide (RB-SiC). The cutting performance of the ball endmills was investigated by examining surface roughness and form accuracy of the machined workpiece as well as tool wear characteristics. It was found that micro lens arrays and grooves with extremely smooth surface and high-accuracy profile could be obtained on oxygen-free copper without detectable tool wear. When machining RB-SiC, although ductile cutting was realized, a few fine streaks were observed on the machined surface, which were attributed to the flank wear of the diamond tool. The effects of tool feed condition on cutting performance of a worn tool was investigated by performing micro grooving tests.
