The surface roughness and the evaluation criteria.
Surface roughness (microgeometry) is a set of irregularities with relatively small steps on the baseline length, forming its topography.
The reasons for the formation of roughness
The roughness after machining is a trace of cutting tools (metal or abrasive), distorted plastic and elastic deformation and vibration of the system.
Roughness after non-mechanical methods of treatment is the result of uneven removal of metal from the surface (electrochemical, electroerosion, etc. processing), as well as copying of irregularities (of microorgani) surface of dies, rolls, molds in the preparation of blanks, etc.
Distinguish roughness: longitudinal, measured in the direction of the vector cutting speed and the shear measured in the feed direction. In most cases, the transverse roughness more longitudinal.
The evaluation criteria of roughness
Given the large influence of surface quality on performance properties of machine parts, the roughness of the bearing surfaces is strictly reglementiert.
Surface roughness is usually determined by its profile, which represents the intersection of the surface with the plane perpendicular to the direction of unevenness on the base length.