by Sam Sam

An Introduction to Surface Roughness

Performing a surface roughness test.

Surface roughness, often shortened to roughness, is a component of surface texture. It is quantified by the deviations in the direction of the normal vector of a real surface from its ideal form. If the deviations are large, the surface is rough; if they are small, the surface is smooth.

Roughness plays an important role in determining how a real object will interact with its environment. Rough surfaces usually wear more quickly and have a higher coefficient of friction than smooth surfaces. A chrome plated product will, typically, have a very low coefficient of friction.

Mean Roughness (Ra)

The mean roughness (roughness average Ra) is the arithmetic average of the absolute values of the roughness profile ordinates. Ra is one of the most effective surface roughness measures, commonly adopted in general engineering practices. This is because it gives a good general description of the height variations in the surface.

All our chrome plated products are produced to < 0.2ym Ra. Read more about our chrome plated products here.