Ahmad K Elshennawy, George F Schrader
Published By: SME
To be globally competitive in precision-engineered products, manufacturers require a high degree of accuracy and precision on the part of the measuring and gaging instruments used to setup machines and evaluate product conformance to specifications. If manufactured parts of a kind are to be interchangeable, all measurements must be based on a set of reliable standards. Metrology, the science of weights and measures, has many applications and requires a wide variety of instruments in just about every facet of science and industry. The coordinate measuring machine (CMM) is a flexible measuring device capable of providing highly accurate dimensional position information along three mutually perpendicular axes. Automated gaging is performed in two general ways. One is in-process or on-the-machine control by continuous gaging of the work. The second way is post-process or after-the-machine gaging control. The quality of surface finish is commonly specified along with linear and geometric dimensions.