The main forms of turning on the outer surface of shaft parts by shaft parts manufacturers are as follows:

(1) Waste car: the blank of free forging and large castings has a large processing allowance. In order to reduce the shape error and position deviation of the blank outer circle, the processing allowance of the subsequent process is uniform. In the outer circle processing based on the removal of the oxide skin on the outer surface, the general cutting allowance is 1-3mm on one side.

(2) roughing: medium and small forging and casting blanks are generally roughed directly. Rough car mainly cut off most of the blank margin (generally out of the ladder profile), in the process system stiffness allows, should choose a larger cutting dosage to improve production efficiency.

(3) Semi-finishing: Generally used as the final machining process of medium precision surface, but also as the pre-machining of grinding and other processing processes. For high precision blank, without coarse car, direct semi - fine car.

(4) Finishing: the final processing procedure of outer surface processing and the pre-processing before the finish processing.

(5) Fine turning: the final processing procedure of high precision and fine roughness surface. It is suitable for the outer surface machining of non-ferrous metal parts, but because non-ferrous metal is not suitable for grinding, it can be used instead of grinding.

However, fine car requires high precision machine tool, good rigidity, smooth transmission, trace feed, no crawling phenomenon. The diamond or hard alloy tool is used in turning, the main deflection Angle of the tool is larger (45 O-90 o), and the radius of the tool tip is less than 0.1-1.0mm, so as to reduce the elastic deformation and vibration in the process system.