Ra means roughness average and it is the universally recognised and most used parameter when it comes to measuring the surface of stainless steel and other metals. It is the arithmetic mean of the departures of the profile from a ‘mean’ or ‘centreline’ and is usually displayed in microns (µm), often with a maximum or minimum requirement such as <0.5µm. In plain English, it measures the peaks and valleys of the surface and gives the average between the two. Other measured finishes such as Rz are also available.
RA Finishes
We are able to measure and certify in both Ra and Rz and can work to minimum or maximum values, as well as specific ranges.
With all Ra Finishes measured and certified you can be confident in the finish received.
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