Surface roughness, often simply called roughness, is a component of surface finish (surface texture). It is quantified by the deviation of the normal vector direction of the real surface from its ideal form. If these deviations are large, the surface is rough; if they are small, the surface is smoot

According to the condition of the workpiece during the measurement process, the roundness meter can be divided into two types: workpiece rotating type and workpiece stationary type.