Differences Between RA and SA
RA (Roughness Average) and SA (Surface Area) are two measurement indicators of surface roughness. RA is the most commonly used two-dimensional roughness parameter, evaluating surface smoothness by calculating the arithmetic mean of the absolute deviations of all points on the surface profile line from the reference line over the measured length. It is typically used for roughness detection on flat surfaces. On the other hand, SA is a three-dimensional surface roughness indicator that takes into account the height variations and other features of the surface profile. It is often used for more complex surface analyses, such as high-precision manufacturing or optical surface treatments. SA provides a more comprehensive view of surface roughness, making it suitable for applications that require detailed three-dimensional data.