Machining details of shaft parts

Machining details of shaft parts

1、 Basic machining route of shaft parts

The main machining situation of shaft parts is the general situation of outer circle and common special shape. Therefore, it is necessary to select the appropriate processing method for bucket force according to the requirements of various Accuracy grades and profile roughness. There are four basic processing routes.

First of all, it is the processing route from rough turning to semi finishing turning, and then to finishing turning, which is also the main process route for the pin cylindrical machining of shaft parts with common materials; The second is from rough turning to semi finishing turning, and then to rough grinding. For ferrous metal materials and parts with high accuracy requirements, general coarseness requirements are small and need to be hardened, this processing route is a good choice for bucket force, because grinding is an ideal subsequent processing procedure for bucket force; The three routes are from rough turning to semi finishing turning, then to finishing turning and diamond turning. This kind of processing route is specially used to process non-ferrous materials. Because the hardness of non-ferrous metals is small, it is easy to block the gap between sand grains. If grinding is used, it is not easy to obtain the required profile roughness, so finish turning and diamond turning must be adopted; The latter processing route is from rough turning to semi finishing turning, then to rough grinding, fine grinding and finishing. This route is often used for the parts which are hardened by ferrous metal and have high requirements for precision and low requirements for coarseness value.

2、 Pre machining of shaft parts

Before turning the outer circle of shaft parts, some preparatory procedures should be carried out, which is the pre machining process of shaft parts. Straightening is an important preparatory process. Because the workpiece blank in the manufacturing, transportation and storage process, often occurs bending deformation. In order to ensure reliable clamping and uniform distribution of machining allowance, straightening is carried out by various presses or straightening machines in cold state.

3、 Positioning datum for machining shaft parts

First of all, the center hole of the workpiece is used as the positioning reference for machining. In the machining of shaft parts, the general situation of each outer circle, the coaxiality of taper hole and thread profile, and the verticality of the end facing torsion axis are all important appearance of position accuracy. These profiles are generally based on the center line of the shaft as the design basis, positioning with the center hole, and the principle of appropriate datum coincidence. The center hole is not only the positioning datum in turning, but also the locating datum and grinding datum of other machining processes. When two center holes are used for positioning, multiple outer circles and end faces can be machined in one clamping process.

Secondly, the outer circle and the center hole are used as the positioning datum. This method effectively overcomes the error and fallacy of poor rigidity of the central hole positioning, especially when machining heavy workpieces, the positioning of the central hole will cause unstable clamping and the cutting parameters can not be too large. If the outer circle and the center hole are used as the positioning datum, there is no need to worry about this problem. In rough machining, the general situation of the shaft’s outer circle and a central hole are used as the positioning reference, which can bear a large cutting torque in the machining, which is a common positioning method for shaft parts.

The third is to take the general situation of two outer circles as the positioning datum of machining. When machining the inner hole of the hollow shaft, the center hole can not be used as the positioning reference, so the general situation of the two outer circles of the shaft should be used as the positioning reference. When machining machine tool spindle, two supporting journal is often used as positioning reference, which can effectively ensure the coaxiality requirement of taper hole relative to supporting journal, and eliminate the error caused by the non coincidence of datum.

The cone plug with a central hole is used as the positioning reference for machining. This method is widely used in the processing of hollow shaft cylindrical profile.

4、 Clamping of shaft parts

The machining of cone plug and cone sleeve mandrel must have high machining accuracy. The center hole is not only the positioning reference for manufacturing itself, but also the datum for finishing the outer circle of hollow shaft. It is necessary to ensure that there is a high coaxiality between the cone surface and the central hole on the cone plug or cone sleeve mandrel. Therefore, when selecting the clamping mode, attention should be paid to reduce the installation times of the cone plug as far as possible, so as to reduce the repeated installation error of the parts. In actual production, the cone plug installation in the future, generally speaking, before the completion of processing, will not be removed or replaced in the middle of processing

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