Abstract: Large machines, especially those having working envelopes in excess of fifteen feet, exhibit unacceptable errors because of thermal expansion and mechanical misalignments between the axes. The present invention uses an interferometric laser tracker or a comparable 3D position sensor to measure the position of a retroreflector attached to the end effector, e.g. a machine head when the machine comes to rest. A computer compares the measured position to the desired position according to the machine media, and adds the appropriate correction with trickle feed media statements to move the machine to the correct position prior to further machining. The present invention scales the media statements for thermal effects in the factory.

Abstract: Product acceptance requires accurate measurement of product features. We augment machine control with true position feedback from an independent measurement system to allow such inspection to occur with conventional machine tools rather than expensive, special purpose, limited versatility Coordinate Measuring Machines.