Manufacture characteristics of CVD diamond tools

Due to its polycrystalline structure, CVD diamond can produce fracture toughness (fracture resistance) over actual natural diamond. This feature has proven to be very beneficial in offensive machining such as interrupted cutting and wheel dressing. In general, the mechanical robustness of CVD diamonds is similar to the robustness of advanced ceramics.
Careful design and fabrication of fracture toughness, strength and other key properties of CVD diamond individual sheets can improve high performance tools for CNC rotating wheel dressing, high speed or near dry machining of aluminum and metal based composites.
The CVD diamond tool is manufactured in a similar manner to the PCD tool. The diamond blade is brazed to the notched corner of the tungsten carbide or high speed steel body, and the tool is refined with a diamond wheel. The sturdy brazing technology of thick-film diamond blades was developed in the 1990s. This technology solves the problem of bonding and tool body selection for metal-cutting films, diamond-coated carbide inserts. The bonding and tool body selection of diamond-coated carbide inserts for cutting has been widely considered to have a negative impact on cutting. Most independent thick film CVD diamond materials for cutting tools are approximately 0.5 mm thick. The relatively smooth, fine-grained (about 1 μm) nucleus surface is generally polished for use as a rake face for cutting tools; the surface of the coarse particles (>50 μm) is vacuum brazed to a tungsten carbide body or a high-speed steel body on.
Although the rigorous control of the CVD process is key, it is the tool manufacturing that ultimately determines the quality of the blade and the robustness of the tool. Most experienced manufacturers often use grinding wheels for the PCD industry, and they extend the grinding time to accommodate the increased hardness of CVD diamond materials.
J&M Diamond Tool Company grinds CVD diamond with a PCD-finished grinding wheel. Compared to PCD tools, it takes 10% to 20% more time to grind a CVD diamond tool blade. However, extending the edge grinding time allows the tool manufacturer to achieve a surface roughness that is superior to that of the PCD tool. Since CVD diamond is more wear resistant than PCD, simply increasing the feed of the grinding wheel creates an excessive grinding force that damages the CVD diamond tool cutting edge.
Thick film CVD diamond can be used to produce a brazed, mirror surface roughness (Ra < 0.05 μm) cutting insert. This unique property of thick film inserts allows the workpiece to produce an excellent surface finish compared to thin film CVD diamond coatings. Thick film CVD diamonds also offer the opportunity to replace single crystal diamond tools in tool selection.
The robustness and wear resistance of the independent CVD diamond material make it an excellent choice for a wide range of machining applications such as high silicon aluminum milling. Tool life for CVD diamond machining of aluminum alloys is often 1.55 times longer than commercial PCD tool life. The actual improvement is determined by the design and manufacturing techniques of aluminum alloys and cutting tools. CVD diamond tools are often used to turn pistons for interrupted cutting required for general machining of aluminum wheel finishing and other high silicon aluminum materials and metal based composites. Although high silicon aluminum is always the subject of CVD diamond concentration research, diamond blade tools are becoming more and more popular in the machining of low silicon aluminum materials. High-productivity machining or precise finishing requires the use of diamond tools. An automotive manufacturing company finishes an aluminum part. The CVD diamond insert tool is not only 30% more durable than the PCD, but it can continuously process the required surface roughness throughout the life of the tool.