Modelling and analysis of uncertainty in the form characterization of ultra-precision freeform surfaces on coordinate measuring machines

This paper presents an uncertainty analysis model for the form characterization of ultra-precision freeform surfaces on coordinate measuring machines (CMM). The model is developed by incorporating the effect of the CMM, the sampling plan, and the evaluation method taking into account workpiece form deviations. It allows the analysis of the uncertainty of evaluated surface parameters with respect to the magnitude of the workpiece form deviation based on Monte Carlo simulation. The effectiveness of the model was successfully verified using a designed freeform artefact on a precision CMM. The model should make the reliable form characterization of ultra-precision freeform surfaces possible.