During the cutting process, the tool wears to a certain limit, the blade edge is chipped or broken, and when the blade edge is wound (plastic deformation), the tool loses its cutting ability or cannot guarantee the processing quality, which is called tool failure. The main forms of tool damage and the countermeasures are as follows: 1, the flank wear: Friction and wear on the flank face due to mechanical stress. Since the tool material is too soft, the back angle of the tool is too small, the cutting speed is too high during the machining process, and the feed amount is too small, resulting in excessive wear of the flank face, which reduces the dimensional accuracy of the machined surface and increases the friction. High-abrasion tool materials should be selected, while reducing the cutting speed, increasing the feed rate, and increasing the tool back angle. This will avoid or reduce the occurrence of flank wear. 2, boundary wear The upper boundary of the main cutting edge is often worn at the interface with the workpiece. The main reason is that the surface of the workpiece is hardened and the serrated chips cause friction, which affects the flow of the chips and causes the chipping. Only by reducing the feed rate of the cutting speed, while selecting the wear-resistant tool material and increasing the rake angle, the cutting edge is sharp. 3, the rake face wear (crater wear): The rake face is worn by frictional diffusion. The rake face wear is mainly caused by the contact of the chip workpiece material and the diffusion of the heat generating region. In addition, the tool material is too soft, the cutting speed is too high during the machining process, the feed amount is too large, and the front blade surface wear is also caused. The wear of the rake face can cause deformation of the tool, interfere with chip removal, and reduce the strength of the cutting edge. Mainly to reduce the feed rate of cutting speed, while selecting the coated cemented carbide material, can reduce the wear of the rake face. 4, plastic deformation The cutting edge is deformed by high temperature or high stress. The cutting speed, the feed rate is too high, and the hard material of the workpiece material acts, and the tool material is too soft, and the cutting edge temperature is high, which causes plastic deformation. It will affect the quality of chip formation and sometimes it can lead to chipping. It is possible to take measures such as reducing the feed rate of the cutting speed and selecting a tool material with high wear resistance and high thermal conductivity to reduce the occurrence of plastic deformation and wear. NANTONG DONOR COMPANY LTD , https://www.ntdonglan.com