Ultraprecision machining of tungsten alloy by applying ultrasonic elliptical vibration cutting

Ultrasonic elliptical vibration cutting' technology is applied in the present research to ultraprecision machining of tungsten alloy, which is expected as a material of molds for glass parts instead of sintered tungsten carbide or CVD-silicon carbide. It is confirmed that ulptraprecision grooving of the tungsten alloy cannot be realized by the ordinary cutting. On the other hand, it can be realized by the elliptical vibration cutting at a cutting depth of less than 0.8 μm. Effects of the cutting distance on the cutting force and the surface roughness are also clarified, and it is found that surface roughness of less than 100 nm Rz can be attained up to a cutting distance of 35 m. Practical molds of the tungsten alloy for spherical glass lenses and a glass prism are successfully machined by the elliptical vibration cutting.