In addition to good tool coatings and cutting fluids, there is also a new process of cutting off the thermal current circuit.
As is well known, during the metal cutting process, high temperatures are generated in the cutting area due to chip deformation and friction. At the same time, due to the different materials of the tool and workpiece, the two poles of the thermocouple are formed, generating thermoelectric potential and direct current. Thermoelectric current can easily enhance the oxidation process on the working surface of cutting tools, accelerating tool wear. Under certain conditions, thermoelectric potential - thermoelectric current - will also be generated in the contact areas between the tool and the machine tool, the workpiece and the machine tool, and the contact areas between the friction pairs of the machine tool itself. During the cutting process, thermal magnetic and electromagnetic effects are also generated, and electron emission discharge phenomena occur on the surface of the high-temperature contact area.
In recent years, research by domestic and foreign scientific and technological personnel has shown that the thermal current generated during the cutting process and the thermoelectric current caused by other factors both form a circuit through the machine tool tool workpiece machine tool system. At the same time, there is also local thermal current circulating in the limited contact area between the tool and the workpiece, which exacerbates the wear of the tool. Therefore, in addition to the basic methods mentioned above, a new approach can also be adopted to improve the cutting performance and durability of cutting tools, which is to combat the thermoelectric current effect that enhances tool wear by cutting off the thermoelectric current circuit.
The method of cutting off the thermal current circuit is very simple. Even if the tool is insulated from the machine tool or the workpiece is insulated from the machine tool, the thermal current cannot pass through the cutting area and form a circuit. This can reduce the affinity between metals, reduce the generation of chip deposits and scales, and improve the cutting performance, durability, and machining quality of the tool.
How to cut off the thermal current circuit. For machinists, use a rubber wood pad or plastic pad on each of the upper and lower surfaces of the turning tool to insulate the upper and lower planes and sides of the tool holder from the square tool holder on the machine tool; For milling and planing workers, if a flat jaw clamp is used to clamp the workpiece, a rubber board or rubber sheet is placed between the clamp and the workpiece to insulate the workpiece from the flat jaw clamp; For drill bits and end mills, high-strength plastic handle drill bits and plastic handle end mills can be used to insulate the tool holder from the spindle hole of the machine tool.
Through production practice, it has been proven that cutting off the thermal current circuit is particularly suitable for processing high-strength, high hardness, and difficult to cut materials in order to demonstrate its effectiveness, usually improving tool durability by 1-2 times. Therefore, it is the simplest and easiest to implement effective method.
