Minimum zone evaluation of circles and cylinders

A strategy for minimum zone evaluation of circles and cylinders is proposed in this work. This strategy employs a non-linear transformation to convert a circle into a line and a cylinder into a plane. A straightness or a flatness evaluation scheme was then employed to obtain appropriate control points and minimum zone deviation for the feature concerned. A series of inverse transformation procedures was then implemented to compute desired feature parameters. Computer simulation results revealed that the proposed minimum zone method can yield a smaller tolerance value than the least-squares method. Also, the sensitivity of the proposed method and the least-squares method to an abrupt peak in the measurement data was addressed.