Surface Roughness Measurement

Definitions and indications for surface roughness parameters for industrial products are specified.

Surface roughness measurement.

Surface roughness is a quantitative calculation of the relative roughness of a linear profile or area expressed as a single numeric parameter r a. Surface roughness value equivalents the waviness is the measure of surface irregularities with a spacing greater than that of surface roughness. The most common method of measuring the surface roughness of gear teeth is with a contact stylus profilometer which typically uses a conical stylus with a spherical tip made from diamond. There are pros and cons to both methods and it is important to select the most suitable instrument based on your application.

Surface roughness often shortened to roughness is a component of surface texture. Surface roughness parameters this section explains the main parameters of iso 4287 1997. Surface roughness also known as surface profile r a is a measurement of surface finish it is topography at a scale that might be considered texture on the surface. Solutions of the ols5000 microscope for surface roughness advantages over a contact stylus.

Surface roughness measurement instruments can be categorized into contact based and noncontact based instruments. Surface roughness is a measurement of surface texture. They are arithmetical mean roughness ra maximum height ry ten point mean roughness rz mean spacing of profile irregularities sm mean spacing of local peaks of the profile s and profile bearing length ratio tp. Roughness plays an important role in various processes such as friction and adhesion and is widely measured.

However in practice it is often necessary to know both the amplitude and freq. Each parameter is classified according to primary profile p roughness profile r and waviness profile w in order to evaluate different aspects of the profile. It is defined as a vertical deviation of a real surface from its ideally smooth form. It is quantified by the deviations in the direction of the normal vector of a real surface from its ideal form.

If they are small the surface is smooth. In surface metrology roughness is typically considered to be the high frequency short wavelength component of a measured surface. Surface roughness cannot be accurately characterized by using a single parameter.