35. Ra - only an Average
These three markedly different surface profiles have the same Ra value
36. Ra Rq
Ra: The Average Roughness Height is
the average absolute distance from the
mean line of the roughness profile within
the evaluation length.
Rq: is the root-mean-square roughness
average deviation from the mean line
within the evaluation length.
37.
38.
39. Rp: is the maximum height of the
Roughness profile above the mean line
Within the evaluation length (5 cutoffs)
Rpm: is the mean of the 5 Rp values in
The successive cutoff lengths
40. ADF Curve
Sk: is the measure of the symmetry of the
ADF curve about the mean line. Negative
Skewness indicates a plateau - dominated
Surface, and a positive skewness indicates
a peak – dominated surface.