The manufacturing process of PCD tool
The PCD tool manufacturing process mainly includes two processes:
PCD composite piece manufacturing: PCD composite piece is made of natural or synthetic diamond powder and combined agent (which contains cobalt, nickel, and other metals) according to certain combinations in high temperature (1000 ~ 2000℃), high pressure (50,000 ~ 100,000 atmospheric pressure) sintering. In the sintering process, due to the participation of the combined agent, the diamond crystals form a joint bridge with TiC, SiC, Fe, Co, and Ni as the main factors, and the diamond crystals are embedded in the framework of the joint bridge in the form of a covalent bond. The composite plate is usually made into a solid disk of diameter and thickness, and the composite plate needs to be polished by grinding and other corresponding physical and chemical treatment.
PCD blade processing: PCD blade processing tension including composite cutting, welding, blade grinding, and other steps. The best tool for grinding PCD blades is .
Cutting technology of PCD composite slice
Because PCD composite tablets have high hardness and wear resistance, special processing technology must be adopted. At present, the processing of PCD composite chip mainly accepts several technological essentials such as EDM wire cutting, laser machining, ultrasonic machining, high-pressure water jet and so on.
Specific forces of PCD composite chip cutting process
Process essentials - process characteristics
Edm - highly combined pulse discharge energy, strong discharge explosive force makes PCD quality guessed metal melt, division diamond graphitization, and oxidation, division diamond fall off, good process, high efficiency.
Ultrasonic processing - low processing efficiency, diamond powder consumption, dust pollution
Laser processing - non - war processing, high efficiency, processing deformation, poor process.
In the above machining essentials, the results of EDM are better. The presence of combined Bridges in PCD makes EDM composite plates possible. In the presence of liquid, the pulse voltage is used to make liquid near the electrode metal to form a discharge channel, and a spark is generated locally. The instantaneous high temperature can make polycrystalline diamond melt and fall off, thus forming the required triangular, rectangular or square cutting head blank. Electrical discharge machining efficiency and appearance quality of PCD compact by cutting speed, PCD grain size, layer thickness and quality of the electrode and the influence of such factors as the cutting speed in the appropriate choice is very crucial, practice shows that increasing the cutting speed is low processing quality in appearance, and the cutting speed is too low will produce "archwire" signs, and low cutting efficiency. Increasing the thickness of the PCD blade also lowers the cutting speed.
The welding process of PCD blade
In addition to accepting mechanical clamping and bonding essentials, the joint essentials of the PCD composite plate and cutter body are mainly determined by brazing essentials to restrain PCD composite plate on the hard alloy matrix. The main points of welding are laser welding, vacuum diffusion welding, vacuum brazing, high-frequency sensing brazing, etc. At present, high-frequency heating brazing with low investment and low cost are widely used in PCD blade welding. In the process of blade welding, the choice of welding temperature, flux, and welding alloy will directly affect the performance of the tool after welding. In the welding process, the control of the welding temperature is very tight, if the welding temperature is too low, the welding strength is not enough. If the welding temperature is too high, PCD is prone to graphitization and may lead to "overburn", affecting the combination of PCD composite plate and carbide matrix. During the actual processing process, the welding temperature (normally less than 700℃) can be controlled according to the holding time and the depth of PCD reddening. Foreign high-frequency welding more accepts automatic welding technology, welding efficiency is high, good quality can achieve continuous production. Domestic acceptance of manual welding, lower production efficiency, quality is not ideal. Demina produces various that can use for grinding and welding technology with high production efficiency.
Grinding process of PCD blade
The high hardness of PCD makes its material removal rate very low (even only 10, 000 percent of the removal rate of cemented carbide). At present, PCD cutting tool grinding technology mainly adopts resin combined with a diamond grinding wheel for grinding. Because the grinding between grinding wheel abrasive and PCD is the interaction between two materials with similar hardness, the grinding discipline-specific force is huge. For high particle size and low speed grinding wheels, the adoption of water-soluble coolant can improve the grinding efficiency and accuracy of PCD. The choice of grinding wheel combination agent depends on the grinding machine example and processing conditions. Since the EDG skill is almost unaffected by the hardness of the workpiece being ground, the adoption of EDG skills in PCD has a great advantage. The grinding of some bulky PCD tools, such as woodworking tools, also has a great demand for this dynamic grinding process. With the continuous growth of EDG grinding skills, EDG skills will become a major growth bias in PCD grinding.
