1. Elements of raw materials processed by CNC processing plants: the hardness of raw materials is small, and the level of cooling and toughness of raw materials with large plasticity is more important.

2. Formal elements of the tool: The rake angle of the CNC machining tool, the fillet of the blade, and the amount of wear behind the tool have a great influence on the cooling hard layer. As the rake angle decreases and the mouth and back wear increases, the depth and hardness of the cold hardened layer also increase.

3. Cutting factors of CNC parts processing: changes in cutting speed and supply have a great impact on cold toughness. When the cutting speed increases, the contact time between the tool and the workpiece processed by the precision parts is short, the level of plastic deformation is small, and the hard layer and hardness are reduced. The feed rate increases, the level of plastic deformation increases, and the level of surface cooling toughness increases.