Because of the high hardness and wear resistance of PCD composite tablets, special processing technology must be adopted. The processing of the PCD composite sheet mainly adopts several technological methods such as EDM line cutting, laser machining, ultrasonic machining, high-pressure water jet, etc. The comparison of technical characteristics is shown in table 1.
Edm – highly concentrated pulsed discharge energy and powerful discharge explosive force make the metal in PCD material melt, some diamond graphitization, and oxidation, and some diamond fall off.
Ultrasonic processing – low processing efficiency, large consumption of diamond powder, dust pollution.
Laser processing – non – contact processing, high efficiency, small deformation, poor process.
Among the above machining methods, the effect of EDM is better. The existence of bonding Bridges in PCD makes it possible to manufacture EDM composites. Under the condition of the working fluid, the pulse voltage is used to make the working fluid near the electrode metal form a discharge channel, and locally generate discharge sparks. Instant high temperature can make the polycrystalline diamond melt and fall off, so as to form the required triangle, rectangle or square blank of the tool head. Electrical discharge machining efficiency and surface quality of PCD compact by cutting speed, PCD grain size, layer thickness, and quality of electrodes. And the influence of such factors as the selection of proper cutting speed is critical, the experimental results show that increasing the cutting speed can reduce machining surface quality, and the cutting speed is too low will produce “archwire” phenomenon, and reduce the cutting efficiency. Increasing the thickness of the PCD blade also reduces the cutting speed.