Diamond film (CVD) tool manufacturing

The production of diamond films (including thin and thick films) using chemical vapor deposition or physical vapor deposition methods has received high attention from many countries, mainly due to its significant application effects and value in mechanical processing, optics, microelectronics technology and other fields.

 

 

Diamond film (CVD) cutting tools have many machining advantages due to their isotropic and polycrystalline planar structure and easy size control, the ability to carry substrates (with hard alloy substrates for easy welding), and the micro blade processing of polycrystalline layers. They can completely replace the complex manufacturing process and expensive natural single crystal diamond cutting tools in the field of precision machining.

 

CVD cutting tools can be processed using high-speed and high feed rate processes, and are not easily damaged in aggressive machining, especially for diamond films with SiC substrates. The compatibility between the two is good, and the film layer is not easily peeled off during use. At the same time, the impact resistance of the substrate and film layer is extremely high, which can also replace PDC cutting tools for precision machining and semi precision machining. Of course, uncoated hard alloy cutting tools and ceramic cutting tools are incomparable.

 

To make cutting tools using diamond film, the first step is to perform cutting. The most effective cutting method is laser cutting, which has the advantages of narrow cutting seams and high efficiency. But it is required to cut in air so that there is no residue left on the incision. If a protective gas such as argon is used, it is not good because graphite products will adhere to the incision and affect the subsequent grinding.

 

 

 

After cutting, blade grinding is required, which includes mechanical grinding (low efficiency, high roughness, up to Ra0.2 μ m or more), ion beam processing (low efficiency, high investment. The advantage is that there is no direct contact during processing, high accuracy, up to Ra0.005 μ m), plasma etching (high efficiency, but requires high temperature), hot metal disk grinding (high efficiency, accuracy up to Ra0.055 μ m, but requires high temperature), and laser beam etching (extremely high efficiency, no direct contact, but accuracy only reaches Ra0.5 μ m). At present, mechanical grinding is mainly used in China, and the quality and grinding efficiency are still difficult to meet the requirements.

 

After cutting and grinding to achieve the desired blade shape, size, and geometric angle, the CVD diamond cutting head can be fixed to the tool holder or pad by welding or other methods. For CVD cutting heads with metal or hard alloy substrates, conventional silver solder can be used for welding; If the pure diamond thick film cutting head is used, silver solder containing strong carbide forming elements should be used for welding, such as silver copper alloy Ag68.8Cu26.7Ti4.5 containing Ti, which requires welding in inert gas or vacuum, followed by slow cooling treatment to reduce stress.

 

Another similar approach to CVD cutting tools is to firmly deposit a thin layer of diamond film on the cutting edge of tools or tool head structures or coatings made of substrate materials suitable for CVD film growth, such as SiC and SiN4. These tools with CVD film coatings also have similar effects to CVD cutting tools when used. DeBeers company has previously used SiC based diamond coated tools to turn 18% SiAl alloy rods, and compared them with polycrystalline diamond (SYNTE) tools and hard alloy (K10) tools under the same conditions. It was found that the service life was second only to polycrystalline diamond tools but much higher than hard alloy tools, and the machining effect was very good.

 

(Since the 1950s, when diamond and CBN superhard abrasives were artificially synthesized, superhard material products(Diamond, CBN) have experienced rapid development. Staring from now on, our company(www.chinadiatools.com) will share some knowledge about diamond manufacturing processes and formulas with everyone. The information shared on this website comes from the public internet information, which is just for exchange and learning. If you have any questions, please contact the customer service contact information on the website.)