The problem of workpiece deformation in mechanical processing is relatively difficult to solve. Firstly, it is necessary to analyze the causes of deformation before taking corresponding measures.

01. The material and structure of the workpiece affect its deformation

The magnitude of deformation is directly proportional to the complexity of the shape, aspect ratio, and wall thickness, as well as to the rigidity and stability of the material. So when designing parts, try to minimize the impact of these factors on workpiece deformation as much as possible.

Especially in the structure of large parts, a reasonable structure should be achieved. Before CNC machining, it is also necessary to strictly control the hardness, porosity and other defects of the blank to ensure the quality of the blank and reduce the deformation of the workpiece caused by it.

02. Deformation caused by workpiece clamping

When clamping the workpiece, the correct clamping point should be selected first, and then the appropriate clamping force should be selected based on the position of the clamping point. Therefore, try to make the clamping point and support point consistent as much as possible, so that the clamping force acts on the support. The clamping point should be as close as possible to the machining surface, and the position where the force is not easy to cause clamping deformation should be selected.

When there are several directions of clamping forces acting on the workpiece, the order of clamping forces should be considered. The clamping force that causes the workpiece to come into contact with the support should be applied first and not too large. For the main clamping force that balances the cutting force, it should be applied last.

Secondly, it is necessary to increase the contact area between the workpiece and the fixture or use axial clamping force. Increasing the rigidity of parts is an effective way to solve clamping deformation, but due to the shape and structural characteristics of thin-walled parts, they have lower rigidity. Under the action of clamping force, deformation will occur.

Increasing the contact area between the workpiece and the fixture can effectively reduce the deformation of the workpiece during clamping. When milling thin-walled parts, a large number of elastic pressure plates are used to increase the stress area of the contact parts; When turning the inner diameter and outer circle of the thin-walled sleeve, whether using a simple open transition ring, or using an elastic mandrel, arc clamping jaws, etc., the contact area of the workpiece during clamping is increased. This method is beneficial for carrying the clamping force, thereby avoiding deformation of precision parts. The use of axial clamping force is also widely used in production. The design and production of specialized fixtures can make the clamping force act on the end face, which can solve the bending deformation of the workpiece caused by thin wall and poor rigidity.