APPLICATION OF DIAMOND-COATED CUTTING TOOLS

Today, diamond-coated cutting tools are used primarily for machining non-ferrous materials such as aluminium-silicon alloys, copper alloys, fibre-reinforced polymers, green ceramics and graphite. The tool life of cemented carbide cutting tools is greatly improved by diamond coating, and typically more than 10 times the tool life is obtained. In this report we will present cutting performances of diamond-coated inserts, twist drills, square end mills and ball nose end mills. Diamond films are usually deposited more than 10 mu m thick to make tool life longer, since tool life is directly related to him thickness. However, increased film thickness caused many problems with cutting performance. The most severe problem was the decrease in the transverse rupture strength of the diamond-coated substrates. Because of this effect, the diamond-coated insert used under high speed and intermittent cutting conditions was supposed to suffer chipping easily.