(1) in order to ensure the machining accuracy, rough and finish machining should be done separately. Because of the rough machining, cutting a large amount of workpiece by the cutting force, clamping force, heat, and surface hardening are remarkable, the workpiece exists inside the large internal stress, if the coarse and rough machining is continuous, fine machining of precision parts for re distribution of stress and quickly lose. For parts with high machining accuracy. Before roughing and finishing, low temperature annealing or aging treatment should be arranged to eliminate internal stress.
(2) reasonable selection of equipment. Rough machining is mainly cut off most of the machining allowance, does not require high machining accuracy, so the rough machining in large power, not too high precision machine tools, precision machining processes require high precision machine tool. Rough and finish machining is carried out on different machine tools, which can not only give full play to the equipment capacity, but also prolong the service life of precision machine tools.
(3) in the process of mechanical processing, the heat treatment process is often arranged. The arrangement of heat treatment process is as follows: in order to improve the machinability of metal, such as annealing, normalizing, quenching and tempering, etc., it is generally arranged before machining. In order to eliminate the internal stress, such as aging treatment, quenching and tempering treatment, etc., it is generally arranged before roughing and finishing. In order to improve the mechanical properties of parts, such as carburizing, quenching, tempering and so on, the general arrangement is carried out after mechanical processing. If there is a large deformation after heat treatment, the final processing procedure must be arranged.
