Comparison of the orthogonal least squares and minimum enclosing zone methods for form error estimation

A source of controversy in geometric tolerance verification is the choice of the estimating method. Two common methods for estimating form errors are compared in this paper: orthogonal least squares and minimum zone. The fundamentals of each method are presented and a simulation comparison based on data collected with a coordinate measuring machine is performed. The study is for both straightness and flatness form tolerances. Based on the simulation, we argue that in most cases the orthogonal least squares method is preferable.