1、 Division of processing stages
1. Finishing stage: the main task is to cut off most of the machining allowance of each machined surface on the blank, so that the blank is close to the finished part in shape and size. Therefore, measures should be taken to improve productivity as much as possible. At the same time, it is necessary to provide a precision benchmark for the semi finishing stage, and leave sufficient and uniform machining allowance.
2. Semi finishing stage: meet certain accuracy requirements and retain certain machining allowance, mainly to prepare for surface finishing. Colleagues finish the processing of some secondary surfaces.
3. Finishing stage: the main task is to ensure that the main surfaces of the parts meet the technical requirements specified in the drawings.
4. Finishing stage: parts with high accuracy and small surface roughness need to be processed according to the finishing stage. Its main task is to reduce the surface roughness or further improve the dimensional accuracy and shape accuracy.
2、 Why stage division
1. Ensure processing quality
During rough machining, the cutting force, cutting heat, cutting allowance and clamping force are large, and the blank itself also has internal stress. After machining, the internal stress will be redistributed, and the workpiece will be deformed. After dividing the processing stages, the errors and deformations caused by rough machining are corrected by semi finishing and finishing, and the accuracy and surface quality of parts are gradually improved.
2. Qualified hydraulic hole locking machine equipment
The machine tool used for rough machining needs to have the characteristics of good commonness, high efficiency and low precision, while the machine tool for finish machining needs to have the characteristics of high precision. Therefore, after dividing the processing stages, we can avoid "lean and coarse", give full play to the performance of the hydraulic hole locking machine and prolong the service life.
3. Easy to organize production
The production conditions required by each processing stage are different. For example, precision processing requires a constant temperature and clean production environment. After dividing the processing stages, the heat treatment process can be arranged between the stages. For precision parts, stress relief and aging treatment after rough machining can reduce the impact of internal stress on finish machining; Arranging quenching after semi finishing is not only easy to meet the performance requirements of parts, but also the quenching deformation can be corrected by finishing process.
4. Find the defects of the blank in time
During rough machining, most of the allowance of the machined surface is removed. When defects are found, they can be scrapped or repaired in time, which is very helpful to avoid the loss of finishing hours.