Positioning base the decision of gear shaft on the surface of the main processing order, to a huge extent depends on selecting locating datum structure features and the main shaft of the shaft parts upon the surface of the primary location accuracy necessity is set the axis as benchmark is the ideal not just make sure that benchmark is unified, and make the locating datum and the look datum coincidence outside planetary gearbox circle intended for crude benchmark additionally, upon both sides of a razor-sharp hole for great benchmark concrete also take note the following points: (1) when the decision between machined surface when the positioning accuracy of high, greatest completed in a clamping surface area processing (2) for rough machining or when two end center holes (such as spindle cone hole) cannot be used intended for positioning, to improve the stiffness of the procedure program 962bd40735fae6cd99ce689704b30f2443a70fcaduring workpiece processing, just cylindrical surface area or cylindrical surface and one end center hole can be used as positioning reference