Introductions for Diamond and Diamond Cutting Tools

Diamond is material with the highest hardness and best thermal conductivity that we’ve known in mineral materials, whose friction wear is only 1/50 ~ 1/800 of cemented carbide compared with a variety of metals and non-metallic materials. It is the most ideal material to make cutting tools.

Natural monocrystal diamond, however, is only used to make jewelry and the ultra precision machining of some non-ferrous metals. Although De Beers, Sumitomo and so on have been in industrialized production of cutting tools with artificial large particle monocrystal diamonds, it still has not entered the stage of a large number of applications.

The cutting edge of diamond cutting tool is very sharp, and the edge roughness is quite small. It also has low friction coefficient, and is not easy to produce built-up edge when cutting, with high machining surface quality. When processing non-ferrous metal, the surface roughness can reach Ra0.012 microns, and the machining accuracy can reach above IT5.

There are three kinds of diamond cutting tools: natural monocrystal diamond cutting tools, overall synthetic polycrystalline diamond cutting tools, diamond composite cutting tools. Natural diamond cutting tools due to high cost and other reasons, it is less used in practical production.

Synthetic diamond is based on the alloy catalyst, and composed of graphite under high temperature and high pressure. Diamond composite cutting tool is to sinter about 0.5 ~ 1 microns diamond on the cemented carbide substrate, and then goes through high temperature and high pressure and other advanced technology. This material is based on cemented carbide substrates, whose mechanical properties, thermal conductivity and coefficient of expansion are similar to cemented carbide, and diamond crystals on the substrate are irregularly arranged, whose hardness and wear resistance are uniform in every direction.