The surface roughness of the machine tool will affect the actual fitting properties and fitting accuracy of the parts.
If the mating surface of the machine tool parts is rough, in the clearance fit, a large shear pressure is generated at the top of the machine tool surface, which is easily cut off during relative movement, which increases the actual fit gap and reduces the fit accuracy; In the interference fit, the convex peaks on the surface are sheared and flattened during assembly, which reduces the actual amount of interference, reduces the strength of the interference fit, and affects the service life of machine tool parts. Therefore, in order to improve the reliability and stability of the fit, the machine tool must specify a smaller roughness value for the surface that has a fit requirement.
The residual stress on the surface will cause deformation or cracks in the parts, causing changes in the shape or size of machine parts, and also has a certain impact on the matching accuracy.