Surface finish parameters

The separation of geometric deviations is necessary to quantify each deviation, independently of the others. There are two standardized methods for separating geometric deviations:

• average line method: this involves filtering the primary profile with a bandpass filter. The differentiation of one deviation from the other is made by considering the distances between two peaks (wavelength). The boundary between two geometric gaps is therefore expressed as a length (cutoff wavelength). The filter generates an average line, hence the name average line method;

• pattern method: this involves breaking down the primary profile into patterns using a "pattern recognition" algorithm....