Adaptive cylindricity measurements with the use of circumferential section strategy

The cross-sectional method is undoubtedly the most widely used method of measuring cylindricity. The method consists of measurements of roundness profiles in several cross-sections of the cylindrical surface. Usually, the distance between subsequent cross-sections is equal. The number of cross-sections used depends on the required accuracy of the assessment of the cylindricity deviation. If one wants to get only rough estimation of the cylindricity deviation, then the measurement can be made in a few cross-sections only. However, if the required measurement accuracy is high, measurements should be carried out in a large number of cross-sections. The consequence of taking the measurements in a large number of sections is significant extension of the measurement time. In this work, an adaptive method of measuring cylindricity is proposed, the purpose of which is to ensure the required measurement accuracy while reducing the necessary number of cross-sections in which roundness profile measurements should be conducted. The proposed strategy is iterative and it is based on carrying out measurements in the cross-sections of the measured part. The proposed method implies two criteria: the correlation coefficient and the predicted values of the form deviations in the non-measured areas of the measured part. The paper presents the fundamentals of the method and the selected results of its practical verification. The experimental results show the ability of the new method to measure the form deviations of cylindrical parts.