THE IMPACT OF POINT SAMPLING STRATEGIES ON ACCURACY OF COORDINATE MEASUREMENTS OF FLATNESS DEVIATION

The modern mechanical engineering is featured by continuous increasing of requirements for manufactured components. In this context, the most important index of component’s quality is the geometric accuracy of their dimensions and shape. At the present stage of manufacturing development, the coordinate metrology seems to be the most versatile and reliable tool to control geometric accuracy of components. The basis of coordinate metrology is the various types of coordinate measuring machines (CMM) used to perform coordinate measurements. However, the performance and reliability of these measurements depend on the correctness of selected measuring strategy. The choice of a correct measuring strategy to provide reasonable balance between accuracy and performance of measurements is the technological problem with no unequivocal solution. In practice, the specified problem is solved with the search of point sampling strategy that suits to estimate the investigated geometry parameter of part with enough accuracy and minimal duration of the measurement. As a rule, this search is produced within the several popular sampling strategies on the basis of CMM operator experience and his individual preferences, what does not ensure the reliable results obtained. The presented article allows facilitating this search, what is based on efficiency analysis for some point sampling strategies relating to the estimation of surface flatness deviation. The data provided in the article allow estimating the influence of sampling size and pattern to the accuracy of deviation evaluation. Additionally, the article considers the problems that regard the selection of optimal movement trajectory for measuring probe under use of various sampling strategies. In this framework, the general conclusions about their efficiency are formulated.