Abstract
Tungsten-based alloys are expected to be new mold materials, replacing conventional sintered tungsten carbide or CVD-silicon carbides, because of their superior thermal properties. However, it is difficult to machine them ultra-precisely because they are brittle materials and induce rapid tool wear. We propose a new method of machining - the cutting-burnishing method, in which the surface roughness is improved by the burnishing effect between the tool and the workpiece. Peripheral cutting experiments were performed using cylindrical workpieces 50 mm in diameter, 10 mm in thickness. Tools of clearance angle 1 deg., 5 deg., 10 deg., cutting edge roundness 0.05 μm, 0.1 μm, 0.3 μm were prepared to investigate the relationship between the burnishing effect and the shape of the tools. We also investigated how the burnishing effect is influenced by the tool materials: alumina ceramic and cemented carbide. The highest quality surface of surface roughness Rz 0.43 μm was achieved with an alumina ceramic tool of rake angle 1 deg., cutting edge roundness 0.05 μm, depth of cut 1 μm. This was achieved at low cost through the use of inexpensive alumina ceramics, and required a short time of only 2 minutes with a cutting speed of 90 m/min.
