CMMs in the quality environment

Co-ordinate measuring machines (CMMs) have revolutionized the dimensional metrology of virtually all types of manufactured components not only for their accuracy, convenience and simplicity of operation, but also because of the range of measurements that can be undertaken. CMMs are frequently used to perform measurements on a vast diversity of components of all sizes that are critical to the performance of, for example, an aircraft or an automobile. The complexity of such measurements is often far beyond the capabilities of conventional dimensional metrology. The purpose of this article is to specify methods of estimating the uncertainty of measurement in co-ordinate metrology. Normally the procedure will be carried out by including all sources of uncertainty that affect a stated measurement, including the influence of the co-ordinate measuring system, environmental effects, the operator variability and any other influencing factors.