Why is the workpiece deformed during machining?

In the cutting process, the workpiece will has the direction of the elastic deformation because of cutting force, which is often appear in the cutter relieving phenomenon. For this tool deformation phenomenon, when finishing, it needs to keep the tool sharp, this can reduce friction between the tool and the workpiece to form a resistance, and improve the cutting tool cooling capacity when cutting and reduce the internal stress involved in the workpiece.

In the milling of plane of large-scale thin-walled parts, using single-edged milling method, the tool parameters selected a larger primary angle and a larger rake angle, the purpose is to reduce the cutting resistance. Due to the cutting of this tool is more brisk, that’s helpful for reducing the deformation of thin-walled parts, so it is widely used in the actual production.

In the turning of thin-walled parts, a reasonable tool angle is important to turning size, thermal deformation, the micro-quality of the workpiece surface. The size of the rake angle affects the cutting deformation and sharpness of the rake angle. The larger rake angle, the smaller cutting deformation and friction, but the rake angle can not be too large, it is easy to reduce the wedge angle of the tool, the tool strength, and make tool cooling worse, wear faster.

In machining process, the tool and the workpiece friction will generate heat, the heat will cause the workpiece deformation, therefore, often choose high-speed cutting. In this process, cutting chips in a short period of time, most of the cutting heat will be taken away by the chips, thus it can reduce the thermal deformation effectively. Besides, during the high-speed machining process, the material softening of the cutting layer is reduced, which can also reduce the deformation of the machined part, which is very helpful for ensuring the precision of size and shape.

Another important factor to ensure part accuracy is the use of a reasonable amount of cutting. In the processing of high precision thin-walled parts, the symmetrical processing is usually used to let the two opposite sides make balanced stress, which can make workpiece to be flat after processing.