1. Machining datum first
In the process of machining, the surface used as the positioning reference should be machined first, so as to provide the precision reference for the subsequent processing as soon as possible. It is called “benchmark first”.
2. Division of processing stages
Surfaces with high machining quality requirements are divided into three stages: rough machining, semi finishing and finishing. It is mainly to ensure the processing quality, to facilitate the rational use of equipment, to facilitate the arrangement of heat treatment process, and to facilitate the detection of blank defects.
3. Face before hole
For the box, bracket, connecting rod and other parts, the plane shall be machined before the hole is machined. In this way, the hole can be machined by plane positioning, ensuring the position accuracy of plane and hole, and bringing convenience to the machining of hole on plane.
4. Finishing
The finishing of the main surface of the workpiece after finishing (such as grinding, honing, fine grinding / rolling, etc.) shall be carried out at the last stage of the process route. The surface finish after finishing shall be over ra0.8um, and slight collision will damage the surface. In China, Japan, Germany and other countries, after finishing, flannelette shall be used for protection, no hands or other things are allowed Parts directly contact the workpiece, so as to avoid damage to the polished surface due to the transfer and installation between processes.
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