When processing the spherical surface, especially the sphere and the curved surface that have passed the quadrant, it is easy to produce shoulders and backs due to improper adjustment. The main reasons are:

System gap caused

In the equipment transmission pair, there is a certain gap between the lead screw and the nut. As the equipment is put into operation, the gap gradually increases due to wear. Therefore, the corresponding gap compensation for the reverse movement is to overcome The main factor that produces the shoulder on the machined surface. The gap measurement usually adopts the dial indicator measurement method, and the error is controlled within 0.01 ~ 0.02mm. It should be pointed out here that the meter base and meter rod should not be extended too high or too long, because the meter base is easily moved by force due to the long cantilever during measurement, resulting in inaccurate counting, and the compensation value is not true.

Uneven workpiece machining allowance caused

Before realizing the design surface of the part, whether the machining allowance of the surface to be machined is uniform is also an important reason for whether the molding surface can meet the design requirements, because the uneven machining allowance is easy to cause "re-imaging" errors. Therefore, for parts with higher surface shape requirements, the machining allowance should be as uniform as possible before forming or by machining one more profile method to meet the design requirements.

Caused by improper tool selection

The tool removes material through the main cutting edge during cutting. However, after the arc has been processed through the quadrant, after the arc is tangent to the tool's secondary cutting edge (the line of intersection between the secondary back and the base surface), the secondary cutting edge may participate in cutting (that is, the back of the shovel). Therefore, when selecting or grinding tools, we must consider the wedge angle of the tool.