Roughness is caused by the friction and extrusion between the tool and the machined surface in the process of machining parts. It is a parameter to measure the roughness of the surface of parts.

The geometrical error of the reaction surface has a close influence on the working accuracy, wear resistance, sealing, corrosion resistance and the coordination between other parts. Below is a comparison table of surface roughness.

The international standard

RZRA

Surface shape

The mirror surface is the most smooth

Foggy mirror

N10.20.025 Mirror gloss surface

N20.40.05 shiny finish

N30.80.1 dark luster surface

N41.60.2 Direction smooth surface of indistinguishable machining traces

N53.20.4 Micro identify the direction of processing traces

N66.30.8 Direction of discernible machining trace

N76.31.6 No visible processing trace semi-smooth surface

N812.53.2 Slight processing trace

N9256.3 Processing traces are visible

N105012.5 Slight knife mark

The rough surface

N1110025 Knife marks visible

N12

20050 Knife marks clearly visible