The manufacturing method of CVD diamond tool is similar to that of PCD cutter. The diamond blade is first brazed on the notched corner of the tungsten carbide or high-speed steel body, and then the tool is finely ground with a diamond wheel. The brazing technology to fix thick-film diamond blades is developed in the 1990s. The technology solves problems of cutting metal for processing thin metal films, bonding diamond coating with carbide blades and choosing right blade body. However, bonding diamond coating with carbide blades and choosing right blade body have been widely agreed as imparting negative impact to cutting. Most independent thick film CVD diamonds for cutting tools are usually about 0.5mm thick. The relatively smooth, fine-grained (about 1µm in diameter) crystal nucleus surface is generally polished and used on the rake of the cutting tool; the coarse-grained surface (>50µm in diameter) on the side is vacuum brazed to the tungsten carbide body or high-speed steel body. Thick film CVD diamond can be finely side ground to produce a brazed, mirror surface (Ra<0.05µm) cutting insert. Compared with thin film CVD diamond coating, the unique performance of thick film blades enables the workpiece to produce an excellent surface. Thick film CVD diamond also provides possibility to replace single crystal diamond tools when choosing tools.
The solidity 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. The use life of CVD diamond tools for processing aluminum alloy is often 1.55 times the that of commercial PCD cutters. The actual improvement depends on the design and manufacturing technology of aluminum alloy and cutting tools. CVD diamond tools are often used to turn pistons for the intermittent cutting required for fine turning of aluminum wheels and general machining of other high silicon aluminum materials and metal-based composite materials. Although high silicon aluminum is always the object of intensive research on CVD diamond, diamond blade tools are gradually becoming more and more common in the machining of low silicon aluminum materials. High-productivity machining or precise finishing require the use of diamond tools. For example, if an automobile manufacturing company wants to perform finishing operations on an aluminum part, the CVD diamond blade tool will not only be 30% more durable than PCD tools, but also can continuously process the required surface roughness through their use life.