Precision machining knowledge

- Jul 01, 2019-

(1) In order to ensure the processing accuracy, the roughing and finishing are preferably carried out separately. Because of the large amount of cutting during roughing, the cutting force and clamping force of the workpiece are large, the heat is generated, and the machining surface has a significant work hardening phenomenon. There is a large internal stress inside the workpiece. If rough and rough machining Continuously, the precision of the finished part will be quickly lost due to the redistribution of stress. For some parts with high machining accuracy requirements. After roughing and prior to finishing, a low temperature annealing or aging treatment should be arranged to eliminate internal stresses.

(2) Reasonable selection of equipment. Roughing is mainly to cut off most of the machining allowance, and does not require high machining accuracy. Therefore, roughing should be carried out on machine tools with high power and low precision. The finishing process requires higher precision. Machine tool processing. Roughing and finishing are processed on different machine tools, which can fully utilize the equipment capabilities and extend the service life of precision machine tools.

(3) In the machining process route, a heat treatment process is often arranged. The arrangement of the heat treatment process is as follows: in order to improve the cutting performance of the metal, such as annealing, normalizing, quenching and tempering, etc., it is generally arranged before the machining. In order to eliminate internal stress, such as aging treatment, quenching and tempering treatment, etc., it is generally arranged after roughing and before finishing. In order to improve the mechanical properties of the parts, such as carburizing, quenching, tempering, etc., it is generally arranged after machining. If there is a large deformation after heat treatment, the final processing must be arranged.