Effect of Sampling Rates Variation during Cylindricity Error Evaluation

Amira A. Khattab, Yasmine Abouelseoud, Mohammad A. Younes

Cylindrical parts are critical elements in many engineering equipment. To perform correctly, their dimensions and cylindricity should be within specified tolerances. Cylindrical parts can be checked using several dedicated and general purpose measuring systems. Coordinate Measuring Machines (CMMs) can been used to probe and scan cylindrical surfaces to evaluate dimensions and form errors. For accurate evaluation of cylindricity error using a CMM, several parameters should be taken into consideration such as measurement strategy, sampling rate, and cylindricity evaluation technique. The large measurement points required need an efficient evaluation algorithm, and due to their advantages, the Minimum Zone Cylindricity evaluation technique (MZC) and Particle Swarm Optimization technique (PSO) are used in this work. The proposed algorithm was developed using Matlab software and applied for the evaluation of cylindricity error of test cylinders. This paper investigates the effect of the change in sampling rate on the value of estimated cylindricity error when using two different strategies, namely, circles and helical. A comparison between both strategies is presented. The effect of the number of scanned circles and helix turns on the estimated cylindricity error is also investigated.  The results showed that sampling rate has more significant effect on the value of estimated cylindricity error than the number of measurement circles or helix turns even for the same number of data points.