In the process of machining, it is easy to cause workpiece deformation due to various machining errors or other wrong operations of processors. This problem is difficult to solve. First of all, we must determine the specific causes of deformation, and then take measures to deal with it. Therefore, what are the main factors that easily cause workpiece deformation in the process of machining?
1. Workpiece deformation caused by workpiece clamping
What are the main factors that easily cause workpiece deformation in machining?
Workpiece clamping is easy to cause workpiece deformation. In order to avoid this deformation, it is necessary to select the appropriate clamping point, and then select the appropriate clamping force according to the position of the clamping point. Therefore, the clamping point and support point of the workpiece should be kept as far as possible, so that the clamping force acts on the support, and the clamping point is closer to the machining surface, so that it is not easy to cause deformation.
When the clamping force acts on the workpiece, the sequence of the clamping force should be considered and the clamping force should not be too large. In order to balance the cutting force, the clamping force should be applied at the end. It is also necessary to increase the contact area between the workpiece and the fixture or use the axial clamping force. The most effective way to solve the clamping deformation is to improve the stiffness of parts. The increase of the contact area between the workpiece and the fixture helps to reduce the deformation of the workpiece in the clamping process.
2. Workpiece deformation caused by workpiece material and structure
The deformation is directly proportional to the shape complexity, length width ratio and wall thickness, and is directly proportional to the stiffness and stability of the material. Therefore, when designing parts, the influence of these factors on workpiece deformation should be reduced as much as possible. In particular, the structure of large parts should be more reasonable. Before processing, hardness, looseness and other defects should be strictly controlled to ensure the quality of the blank and reduce the deformation of the workpiece.
3. Workpiece deformation caused during machining
In the cutting process, the workpiece is subjected to the cutting force, resulting in the phenomenon of cutting tool. This is the elastic deformation in the direction of the force. In order to solve this deformation problem, the tool can be improved, which can reduce the friction between the tool and the workpiece, improve the cooling capacity of the workpiece in the cutting process, and reduce the internal stress of the workpiece.
4. Workpiece deformation caused by stress after machining
Workpiece deformation caused by workpiece machining
After machining, the part itself has a relatively balanced internal stress state. Although the shape of the part is relatively stable at this time, the internal stress will change after removing some materials and heat treatment, so it is necessary to restore the balance of force. In this case, it should be improved, which can be solved by heat treatment. Fold the workpiece that needs to be straightened to a certain height, press the tooling into a flat state, and then put the tooling and workpiece into the heating furnace together, and choose different heating temperature and time according to different part materials. After thermal straightening, the internal structure of the workpiece can remain stable. At this time, the workpiece not only has high straightness, but also eliminates work hardening, which is convenient for further finishing of parts.
5. Summary
For workpieces that are easy to deform in machining, corresponding improvements should be made in the blank and processing technology. The above points are the main factors that are easy to cause workpiece deformation in machining. When training machining operators, all large machining plants should pay attention to letting operators understand these main factors that cause workpiece deformation.