Shaft parts are a common type of component with a rotating structure and a length generally greater than the diameter. They are widely used in various mechanical equipment to support transmission components, transmit torque, and bear loads. The machining of shaft parts should follow certain rules. This article can help you understand the specific machining steps and some issues that need to be noted.

1、 Basic machining route for shaft parts

The main machining surfaces of shaft parts are the outer circular surface and common special shaped surfaces, so the most suitable machining method should be selected according to various precision levels and surface roughness requirements. The basic processing routes can be summarized into four.

The first route is the machining route from rough machining to semi precision machining, and then to precision machining. This is also the most important process route selected for the needle outer circle machining of commonly used shaft parts; Next is the processing route from rough turning to semi precision turning, then to rough grinding, and finally to precision grinding. For black metal materials with high precision requirements, small surface roughness requirements, and parts that require quenching and hardening, this processing route is the best choice because grinding is the most ideal subsequent processing process;

The third route is from rough turning to semi precision turning, and then to precision turning and diamond turning. This processing route is specifically used for processing non-ferrous metal materials because non-ferrous metals have lower hardness and are prone to clogging the gaps between sand particles. Grinding is usually not easy to obtain the required surface roughness, and precision turning and diamond turning processes must be used.

The last processing route is from rough turning to semi precision turning, then to rough grinding, precision grinding, and finally to finishing processing. This route is often used for parts made of black metal materials that have undergone quenching and require high precision and low surface roughness values.

2、 Pre machining of shaft components

Before turning the outer circle of shaft parts, some preparation processes need to be carried out, which is the pre machining process of shaft parts. The most important preparation process is straightening. Because the workpiece blank often undergoes bending deformation during manufacturing, transportation, and storage. In order to ensure reliable clamping and uniform distribution of machining allowance, various presses or straightening machines are used for straightening in the cold state.

3、 Positioning reference for machining shaft parts

Firstly, the center hole of the workpiece is used as the positioning reference for machining. In the machining of shaft parts, the coaxiality of the outer circular surfaces, taper holes, and threaded surfaces, as well as the perpendicularity of the end faces to the axis of rotation, are important manifestations of positional accuracy. These surfaces are generally designed based on the centerline of the axis, positioned with a center hole, in accordance with the principle of reference coincidence. The central hole is not only the positioning reference during turning, but also the positioning reference and inspection reference for other machining processes, in accordance with the principle of unified reference. When using two center hole positioning, multiple outer circles and end faces can be machined to the maximum extent in one clamping.

Secondly, the outer circle and central hole serve as the positioning reference for machining. This method effectively overcomes the disadvantage of poor rigidity in the positioning of the center hole, especially when machining heavy workpieces. The positioning of the center hole can cause unstable clamping and the cutting amount should not be too large. By using the outer circle and central hole as the positioning reference, there is no need to worry about this issue.