The structure and characteristics of diamond drill bits
Diamond bit cutting tooth materials are divided into two categories: natural diamond and synthetic diamond. Diamond is a crystal of carbon. The crystal structure is a regular tetrahedron. The carbon atoms are connected by covalent bonds. The structure is very stable. Typical shapes include cubes, octahedrons and dodecahedrons. Diamond is the hardest material, the strongest compressive strength, and the highest wear resistance among the materials currently known to mankind. Therefore, it is the most ideal material for the cutting edge of a drill.
However, diamond as a material for the cutting edge of a drill bit also has major weaknesses.
First, its brittleness is relatively large, and it will crack when encountering impact load.
Second, its thermal stability is poor. Diamond burns into carbon dioxide and carbon monoxide (carbonization) at high temperatures. In the air, between about 455 and 860°C, the diamond will undergo graphitized combustion; in inertness or reducibility There is no oxidation in the gas, but at about 1430°C, the diamond crystals will suddenly burst and become graphite.
Therefore, in the design, manufacture and use of diamond drill bits, it is necessary to prevent the diamond material from being subjected to high impact loads and to ensure timely cooling of the diamond cutting teeth.