Stress deformation during CNC machining can significantly affect the dimensional accuracy and surface quality of workpieces, leading to product failures. To control stress deformation, several effective methods can be employed.

　　Firstly, The selection of cutting parameters has a profound impact on stress generation. A high - speed, low - feed cutting strategy is often beneficial as it reduces the heat input into the workpiece, minimizing thermal stress. For example, when machining thin - walled parts, a small depth of cut combined with a high spindle speed can prevent excessive deformation caused by large cutting forces. Additionally, the sequence of machining operations should be carefully planned. Rough machining should be separated from finish machining, allowing the workpiece to relieve some of the internal stresses generated during roughing before the final precision operations.

　　Secondly, Rigid and well - designed fixtures can effectively restrain the workpiece during machining, reducing the freedom for deformation. However, it is important to avoid over - clamping, which can introduce additional stresses. Elastic fixtures or fixtures with adjustable clamping forces can be used to balance the clamping force and deformation. For instance, vacuum chucks are suitable for holding thin and flat workpieces, providing a uniform clamping force without causing excessive deformation.

　　Material selection and pre - treatment also play important roles. Materials with good machinability, such as some aluminum alloys, are less likely to deform during machining. Heat treatment processes like annealing or stress - relieving before machining can reduce the initial internal stresses in the material, making it more stable during CNC machining.