Minimum zone evaluation of surfaces

Abstract The surfaces that are obtained by various machining and finishing processes deviate from the specified geometry. The evaluation of such surfaces for straightness, flatness, circularity, etc. are given by ISO in terms of the minimum zone values. But no specific methods to obtain the minimum zone values are available. Hence an attempt has been made in this paper to present different methods developed at Central Machine Tool Institute (CMTI) for such applications. The present paper deals with the evaluation of spherical, cylindrical and flat surfaces for sphericity, circularity, flatness etc. in terms of minimum zone deviation. Monte Carlo technique, normal least squares fit, simplex search and spiral search techniques were applied. Monte Carlo, simplex and spiral search techniques were found suitable for minimum zone evaluation.