A New Approach to Form Error Determination in Sculptured Surface Metrology

Abstract

This thesis presents a new approach to the determination of sampling points for CMM inspection of sculptured surfaces, for when the surface equations are not available. It is an implementation-based methodology that relies on commercial CAD/CAM software to determine the Cutter Location (CL) points. Using these CL points, cubic splines are formed, and the maximum curvatures points are found out. These maximum curvature points are inspected using CMM. After performing measurement, suitable localization of coordinate data is performed. These measured points are then compared with the original designed surface and the deviation between the surfaces are calculated. These are termed as profile form tolerances. Further, using the sign convention of the curvatures and the transition of signs, inflection points are determined. These are used to determine profile position tolerances. Sample parts are machined, and the methods developed in this work are validated. These investigations are preliminary and must be studied in further detail through experimentation and analysis for creating formal methodology for verifying sculptured surfaces. Determination of the sampling points is quite important for the newer generation of cyber physical systems whereby suitable control can be provided to manufacturing and inspection equipment. This is again suggested for further research.