Diamond chisel into single crystal diamond material (there are two kinds of natural and man-made, natural single crystal diamond expensive part is replaced by synthetic single crystal diamond), synthetic polycrystalline diamond (PCD) and synthetic polycrystalline diamond and carbide composite Blade (PCD / CC) and CVD diamond.
Single crystal diamond
Single crystal diamond cutting tool must be used for large particles (mass greater than 0.1g, most trails length not less than 3mm), mainly used in surface roughness, geometry, accuracy and dimensional accuracy with higher requirements for precision and ultra-precision machining applications fields.
Natural diamond single crystal diamond is the most wear-resistant material. Fine texture of its own, after fine grinding, edge radius blunt the cutting edge can be as small as 0.008 ~ 0.005μm. But natural single crystal diamond is brittle, and its crystalline anisotropy, the hardness of different crystal planes or the same planes were different in different directions, you must select the appropriate direction during grinding and use. Since the use of harsh conditions, with limited natural single crystal diamond resources, the price is very expensive, so they use a PCD production, PCD / CC and CVD diamond chisel. Natural single crystal diamond is mainly used in some ultra-precision machining non-ferrous metals or gold jewelry production.
The size, shape and properties of synthetic single crystal diamond has a good consistency, because the high temperature and pressure technology matures, capable of producing a certain size synthetic single crystal diamond, especially when machining high wear layered wood, its performance superior to PCD diamond without causing premature edge passivation.
Synthetic polycrystalline diamond (PCD) and synthetic polycrystalline diamond and carbide composite blade (PCD / CC)
PCD is at high temperature (about 1800 ℃), high pressure (5 ~ 6MPa), the use of cobalt and other metal-bonded diamond crystals will be a lot of dust into the polycrystalline polycrystalline material, although slightly lower than the hardness of single crystal diamond, but it is aggregation of randomly oriented diamond grains, is isotropic, when used as a cutting tool can be any orientation sharpening, no natural diamond that must be selected as the best of the cleavage plane as rake faces. When cutting, the cutting edge is very sensitive to accidental damage, wear resistance is also strong, may maintain a sharp cutting edge for a long time, can be very high cutting speed and a larger amount of back cutting machining (eating deep) life is generally higher than WC-based cemented carbide cutting tools 10 to 500 times, and because the PCD metal binding agent has conductivity, so that PCD easy to cut to shape, and a rich source of raw materials, the price is only one of the very few natural diamonds a fraction of one to ten, has become a traditional WC-based cemented carbide cutting tools, high-performance alternatives.
In order to improve PCD insert toughness and weldability, with cemented carbide substrate, on the surface layer of the sintered or pressed PCD 0.5 ~ 1mm thick, which consists of diamond composite blade (PCD / CC). PCD / CC welding or machine clip mode available production tools. Because of its good weldability, regrinding easy, low cost, it is widely used. Hereupon, PCD and PCD / sharp edge and surface quality are not as good CC single crystal diamond tool, while its workability is poor, the grinding ratio is small, it is difficult arbitrarily shaped according to the geometry of the tip, still not flutes break easily manufactured with indexable end mills and other geometric shapes and complex products.
CVD diamond is a pure diamond material of high abrasion resistance, without binding agent, which is at low pressure (<0.1MPa) under preparation. There are two main forms of CVD diamond CVD film coating (CD) and CVD thick film (TFD).
CD is a (chemical vapor deposition) process using CVD, depositing a layer thickness in the cemented carbide substrate (commonly K alloy) approximately 10 ~ 30μm, a film composed of polycrystalline diamond formed.
Because the matrix is easy to shape into complex, it applies to geometrically complex tools, such as taps, drills, end mills and with chipbreakers indexable blade. Municipal court has international tools CD tools, like Sweden's Sandvik CD1810 and the United States Kennametal's KCD25, mainly non-ferrous metals and non-metallic materials for high-speed precision machining, tool life than uncoated carbide tools increased by nearly ten times or even several times. But CD tool suitable for machining a metal composite material, because the composite hard particles in a very short period of time will be the tool surface layer coating worn, so even though the price of CD tool PCD cutting tools lower than similar, However, due to the smaller diamond film adhesion between the materials and the substrate, thus limiting its wide application.