Surface roughness of CNC machining and its influencing factors

The geometric characteristics of machined surface include surface roughness, surface waviness and surface processing texture. Surface roughness is the basic unit of geometric features of machined surface.

When machining the workpiece surface with metal cutting tools, the surface roughness is mainly affected by geometric factors, physical factors and machining process factors.

1. Geometric factors:

From the perspective of geometry, the shape and geometric angle of the tool, especially the arc radius of the tool tip, the main deflection angle, the auxiliary deflection angle and the feed rate in the cutting parameters, have a great influence on the surface roughness.

2. Physical factors:

Considering the physical essence of the cutting process, the round corner of the cutting edge and the extrusion and friction behind the tool make the metal material plastic deformation and seriously deteriorate the surface roughness. When plastic materials are processed to form banded chips, chips with high hardness are easy to form on the rake face. It can replace the rake face and cutting edge for cutting, and change the geometric angle and back draft of the tool. The contour of the chip accumulation tumor is very irregular, so there are knife marks with changing depth and width on the surface of the workpiece. Some chip nodules are embedded in the workpiece surface, which increases the surface roughness. The vibration during cutting increases the parameter value of workpiece surface roughness.

3. Process factors:

Considering its influence on the surface roughness of the workpiece from the perspective of technology, there are mainly factors related to cutting tools, workpiece materials and processing conditions.