1、 The material and structure of the workpiece will affect the deformation of the workpiece
The amount of deformation is directly proportional to the complexity of the shape, the length width ratio and the wall thickness, and is directly proportional to the rigidity and stability of the material. Therefore, the influence of these factors on workpiece deformation should be minimized when designing parts.
In particular, the structure of large parts should be more reasonable. Before processing, the hardness, looseness and other defects of the blank should also be strictly controlled to ensure the quality of the blank and reduce the deformation of the workpiece.
2、 Deformation caused by workpiece clamping
When clamping the workpiece, first select the correct clamping point, and then select the appropriate clamping force according to the position of the clamping point. Therefore, the clamping point should be consistent with the support point as far as possible, so that the clamping force acts on the support. The clamping point should be as close to the machining surface as possible, and the position where the force is not easy to cause clamping deformation should be selected.
When there are clamping forces acting in several directions on the workpiece, the sequence of clamping forces should be considered. For making the workpiece contact with the support, the clamping force should act first, and it is not easy to be too large. For the main clamping force that balances the cutting force, it should act last. Secondly, the contact area between workpiece and fixture should be increased or axial clamping force should be adopted. Increasing the rigidity of parts is an effective way to solve clamping deformation.
3、 Deformation caused by workpiece processing
Due to the cutting force, the workpiece will produce elastic deformation in the direction of the force in the cutting process, which is often referred to as the phenomenon of making the knife. Corresponding measures should be taken on the tool to deal with such deformation. During finishing, the tool should be sharp, which can reduce the resistance formed by the friction between the tool and the workpiece on the one hand, and improve the heat dissipation capacity of the tool when cutting the workpiece on the other hand, so as to reduce the residual internal stress on the workpiece.
4、 Stress and deformation after machining
After processing, there are internal stresses in the part itself, and these internal stress distributions are in a relatively balanced state. The shape of the part is relatively stable, but the internal stress changes after removing some materials and heat treatment. At this time, the workpiece needs to reach the balance of stress again, so the shape changes. To solve this kind of deformation, the workpiece that needs to be straightened can be stacked into a certain height through heat treatment, and then pressed into a flat state with a certain tooling, and then the tooling and workpiece can be put into the heating furnace together, and different heating temperatures and heating times can be selected according to different part materials. After hot straightening, the internal structure of the workpiece is stable.