Selective Zone Search Method for Evaluation of Minimum Zone Sphericity

Accuracy, robustness and speed are essential components of every precision engineering procedure. With the availability of high speed inspection machines and the ability to generate large datasets with minimal effort and time, the evaluation algorithm becomes a critical component of the inspection time. This paper presents a new approach for evaluation of minimum zone sphericity tolerance using a selective zone search method. The method uses geometric constructs to identify the five extreme points required to generate the two minimum zone spheres. Four different models have been developed to investigate all possible combinations for the tolerance evaluation, viz. 4-1, 3-2, 2-3 and 1-4 models. The robustness of the algorithm has been tested using various simulated and reported datasets and the results have been found to be comparable to existing methods. The presented algorithm has also shown considerable savings in time compared to a nonlinear optimization formulation for minimum zone sphericity evaluation.