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Shaft parts is a common type of parts, its structure for the rotating body, length is generally greater than diameter, in a variety of mechanical equipment is widely used to support transmission parts, transmission torque and load. Shaft Parts Processing to follow certain laws, you can understand the specific processing steps and need to pay attention to some issues.
1.Basic Processing Route for Shaft Parts
The main processing surface of shaft parts is the cylindrical surface and common special surface, so we should choose the most suitable processing method according to various precision grades and Surface roughness requirements. Its basic processing routes can be summed up into four.
The first is the processing route from roughing to semi-finishing, and then to finishing. This is also the most important process route chosen for the needle cylindrical processing of commonly used material shaft parts. The second is from roughing to semi-finishing, and then to rough grinding, finally, the fine grinding process is the best choice for the parts that require high Ferrous materials and precision, small Surface roughness and need to be hardened, the third route is from rough to semi finished to finished to diamond and diamond Non-ferrous metal, which are used exclusively for the processing of Non-ferrous metal materials because of their low hardness, the gap between the sand grains is easily blocked, the required Surface roughness is usually not obtained easily by grinding, and the finishing and diamond turning processes must be used; the final processing route is from rough turning to semi-finished turning, then to rough grinding and fine grinding, final finishing is a common process for Ferrous parts that have been hardened and require high accuracy and low Surface roughness.
2.Pre-processing of shaft parts
Before turning the outer circle of Shaft Parts, some preparation procedures should be carried out, which is the pre-processing process of shaft parts. The most important preparation is straightening. Because the workpiece blank in the manufacturing, transportation and storage process, often occur bending deformation. In order to ensure reliable clamping and uniform distribution of machining allowance, in the cold state, through a variety of press or straightening machine to straightening.
3.Positioning reference for machining shaft parts
First, the center hole of the workpiece is used as the locating datum for machining. In the processing of shaft parts, the coaxiality of the outer surface, the surface of taper hole and thread, and the verticality of the end face to the axis of rotation are all the important embodiment of position accuracy. These surfaces are generally designed with the Axis centerline as the design reference, with the center hole positioning, in line with the principle of reference coincidence. The center hole is not only the positioning datum of turning, but also the positioning datum and checking datum of other machining processes. When two center holes are used for positioning, a plurality of outer circles and end faces can also be processed in a clamping operation to the maximum extent.
Secondly, the external circle and the center hole are used as the machining positioning datum. This method effectively overcomes the disadvantages of the bad rigidity of the center hole location, especially for heavy workpieces, the center hole location will cause the clamping instability and the cutting quantity can not be too large. This is not a problem if the outer circle and center hole are used as the positioning datum. In rough machining, using the cylindrical surface of shaft and a center hole as the locating datum can bear the bigger cutting moment, which is the most common locating method for shaft parts.
The third is to take two cylindrical surface as the processing positioning standard. When machining the inner hole of the Hollow Shaft, the center hole can not be used as the positioning datum, so the two cylindrical surfaces of the shaft should be used as the positioning datum. When machining machine tool spindle, two support axles are often used as positioning reference, which can effectively ensure the coaxiality of taper hole relative to support axles and eliminate the error caused by the misalignment of the reference.
finally, the cone plug with the center hole is used as the positioning reference for processing. This method is most commonly used in outer circle surface machining of hollow axis.
4.Foldering of shaft parts
The machining of the taper plug and the taper sleeve mandrel must have higher machining precision. The center hole is not only the positioning datum of the manufacture itself, but also the datum of the hollow shaft external circular finish machining, must ensure that the cone plug or cone sleeve spindle on the cone and the central hole has a high degree of coaxiality. Therefore, in the choice of clamping method should be noted to minimize the number of cone plug installation, so as to reduce the repeated installation error parts. In actual production, after the cone block is installed, generally speaking, it will not be removed or replaced in the middle of the processing before it is finished.