Coborn’s machines are designed for processing the world’s two hardest and most extreme materials: diamond (or ‘cubic carbon’) and its structurally similar sister cubic boron nitride (cBN). Our machines can also easily grind and shape traditional hard tool materials, such as cemented carbide and ceramics. Numerous forms and formats of diamond and cBN are now available and each has required the engineering of a specialist processing solution.
Polycrystalline diamond (PCD) is composed of fine synthetic diamond powder which has been fused by HPHT into coherent blocks or bonded as a flat or a shaped layer on a carbide substrate. PCD is only slightly less hard than SCD but hardness and wear resistance is the same in all directions. Its greatest application is in cutting tools for non-ferrous work pieces in mass production.
Mono Crystal Diamond (MCD) is the term usually used when referring to synthetic single crystals of diamond made by high pressure, high temperature (HPHT) techniques. The crystals are typically slightly yellow rather than white/transparent in colour. These crystals require machines for lapping, grinding and polishing into cutting tools, wire drawing dies, dressers and heat spreaders for example.
Laboratory grown, synthetic diamond. SCD is the hardest material known and, being brittle, is sensitive to shock and vibrations. In the form of large crystals, rather than powder, the term SCD usually refers to mined diamond. Its main applications are for gem jewellery and as nano-scale precision cutting tools for use in the hi-tech electronic and optical industries.
Like diamond, cBN powder can be fused into coherent blocks or as layers on a carbide substrate to give polycrystalline cBN (PcBN). PcBN is typically a mixture of cBN particles and a ceramic binder. Its key advantage is better stability than PCD in contact with ferrous (iron) work piece materials.
CVD Diamond Tooling
Chemical vapour deposition (CVD) is a relatively new way of growing synthetic diamond (e.g. cubic carbon) from a carbon rich gas. Large plates can be produced in both polycrystalline and single crystal forms. As with SCD and PCD, machines are needed to lap these diamond plates flat and to produce useful shaped products such as cutting tools, dresser rolls, hi-tech windows and substrates.