The roughness testers are used to determine the surface roughness. For this, a two- or three-dimensional profile of the surface is measured. Different roughness parameters that characterize the surface roughness are calculated using standardized methods.

The roughness parameters

Ra = arithmetic mean roughness
Ra is the generally accepted and internationally applied parameter for roughness. It is the arithmetic mean of the absolute values of the profile deviations within the sample. The measured value Ra is always smaller than the one observed on the same roughness Rz.

Rz = average roughness
The average roughness Rz is the arithmetic mean of the highest single roughness depths of several adjoining sampling lengths

Rt = maximum roughness height
The vertical difference between the lowest scoring and the highest peak of the total measurement path

Rq = square roughness
Rq is the root mean square average of the roughness profile ordinates

Phynix offers three portable devices for roughness testing that allow the measurement of Rz, Ry, Ra, Rq and Rt: