Dynamic Referencing in 3D Optical Metrology for Higher Accuracy in Shop Floor Conditions

This paper describes the principles of dynamic referencing for optical CMMs and demonstrates the advantages of this new functionality in terms of measurement accuracy in shop floor conditions. Recent optical triangulation–based CMMs are now able to simultaneously measure multiple 3D points. With the help of markers placed on the part being measured, it is now possible to continuously monitor any deviations from the reference part. In this way, the machine reference and part reference become one and the same and remain locked on the part throughout the measuring process. This significantly improves the accuracy of portable CMMs operating in challenging shop floor environments that are subject to intense vibrations, thus eliminating the need to acquire expensive heavy equipment to ensure measurement accuracy. This article describes the vibration conditions common in factory environments as well as the experiments we designed to reproduce these disturbances and assess their impact on measurement processes using a portable CMM. We conclude with examples from real-life situations.