PCD tools are body made by welding PCD composite sheets to carbide or steel cutter bodies. Since the PCD composite sheet combines the high hardness, wear resistance, low friction coefficient and strength of crystalline diamond with the high bending strength of tungsten carbide, the tungsten carbide carbide layer of the composite sheet provides mechanical support for the diamond layer. support, increasing its bending strength, while the carbide layer is easily weldable, making it easy to create the finished tool.
In recent years, as the automotive manufacturing industry has adopted a large number of lightweight materials, such as aluminum alloys, composite materials, etc., the application of diamond tools has also increased significantly. When using PCD tools to process aluminum alloys, due to the high hardness of diamond, the affinity between the surface and the metal is small, and the rake surface of the tool is polished to a mirror surface, which is less likely to produce built-up edge, and the processing dimensional stability and surface quality are very good. PCD tools are used to process aluminum alloy parts of various specifications, and the tool life can reach thousands to tens of thousands of pieces. It is especially suitable for the mass production of automobile and motorcycle parts.
In China's automotive manufacturing industry, PCD tools are mainly used to cut aluminum alloy engine blocks, cylinder heads, transmission casings, valve bodies, tanks, side covers and other parts. Using PCD cutting tools to process automobile aluminum alloy parts can overcome the damage to the tool tip caused by hard points in the aluminum alloy and eliminate built-up edge to the greatest possible extent. It can achieve satisfactory processing results and stable accuracy. In addition, PCD cutting tools are also widely used for high-speed processing of other non-ferrous metals and non-metallic materials, and are widely used in automobiles, aerospace, electronics, wood processing and other fields.
The manufacturing method of PCD cutting tools includes the following steps:
1) Provide a mixed material and add it to the mold for heating and pressurization to obtain the PCD;
2) Press the PCD layeronto the cemented carbide substrate through high temperature to obtain the PCD composite sheet;
3) Cut the PCD composite sheet into several PCD inserts;
4) Coat the upper surface of the tool base with filler metal, place the carbide base on the tool base coated with filler metal and then braze it to obtain a PCD tool, and put the PCD tool into a vacuum furnace for slow cooling;
5) According to the design requirements of the concave complex contour tool edge, use the laser cutting device to laser cut the PCD tool;
6) PCD layer decobalt treatment: Use dispersion coating method, spray Teflon on the outer surface of the part except the polycrystalline diamond layer, put the coated PCD tool into the cobalt removal solution, and heat it at a certain temperature Next, stir the cobalt removal solution (including 20-40wt% sulfuric acid, 80-60wt% ammonium persulfate) evenly and react for a certain time; then take out the PCD tool
The manufacturing process of PCD cutting tools determines their cutting performance and service life, and is the key to the development and application of PCD cutting tools. The processing of PCD inserts includes steps such as cutting of PCD composite sheets, blade welding and sharpening. The traditional method of manufacturing PCD tool edge is grinding wheel grinding and electric discharge machining. The sharpening wheels used in PCD tool edge manufacturing are relatively expensive, and the PCD material has high hardness and is difficult to grind, which undoubtedly brings high costs to PCD tool processing; the PCD tool edge produced by EDM is of poor quality and may collapse. The defect situation is serious. Even if the processing technology is strictly controlled, the chip size is ≥10 μm, and the surface damage of the EDM-processed composite sheet is light and the surface is relatively flat, which has a great impact on the internal structure. After processing, the tool is prone to various use defects.