Ultra-fine nanocrystalline diamond precision cutting tool and manufacturing method therefor

An ultra-fine nanocrystalline diamond cutting tool, which is composed of a handle and a diamond cutter, wherein the diamond cutter is made of a self-supporting ultra-fine nanocrystalline diamond thick film;

• wherein which the thick film has a thickness of 100-3000 μm and has a diamond grain size of 1 nm-20 nm;
• wherein, the surface of the thick film is smooth;
• wherein, the ultra-fine nanocrystalline diamond cutting tool is prepared through the following steps:
• (i) growing an ultra-fine nanocrystalline diamond layer with a thickness of 5 to 200 μm on a surface of a silicon wafer by direct current hot cathode glow discharge chemical vapor deposition;
• (ii) growing ultra-fine nanocrystalline diamond on the ultra-fine nanocrystalline diamond layer by hot filament chemical vapor deposition to obtain an ultra-fine nanocrystalline diamond thick film;
• (iii) separating the ultra-fine nanocrystalline diamond thick film from the silicon wafer, thereby obtaining the self-supporting ultra-fine nanocrystalline diamond thick film;
• (iv) cutting the self-supporting ultra-fine nanocrystalline diamond thick film into a blade shape, welding it to the handle, and then edging, coarsely grinding, and finely grinding, thereby obtaining the ultra-fine nanocrystalline diamond cutting tool.