The surface quality is one of the most important characteristics. It is in a high position in metrology.
People used to make a general assessment of the surface Roughness with standard specimen by observing with eyes or touching with hand.
As the progress of manufacture technology, the demand for the quality of the processing surface is getting higher and higher.
And so is the gauge used for testing surface roughness, nowadays, in all of the testers the pot-ball surface roughness tester, which is quicker, more convenient and more accurate, is most wildly used.
In protective coating applications there is a requirement to measure surface roughness.
Measurements of Surface Roughness are expressed in terms of Ra, Rz . These values include peak-to-valley profile measurement in combination with an assessment of the frequency of peaks within the sample area.