Small data set analysis in surface metrology: an investigation using a single point incremental forming case study.

A new method for applying statistical techniques with small data sets in surface metrology is demonstrated. This method allows for surfaces or surface-creation processes to be differentiated with as few as six measurement regions. A case study in surface roughness of single point incremental forming is used to demonstrate this method because previous work in this area has not provided quantitative statistical testing to support conclusions. The results from the case study indicate that surface roughness parameters Sz and relative length at scales less than 200 nm are greater when the roll marks on the surface are oriented perpendicular rather than parallel to the forming direction.