Dynamic evaluation of spatial CNC contouring accuracy

An instrument capable of measuring arbitrary, dynamic CNC tool paths through three-dimensional space with micrometer-level accuracy is developed and tested. The instrument uses three Laser Ball Bars simultaneously (i.e., simultaneous trilateration) to allow for dynamic path measurements. The design of the instrument is described. The performance is verified by static repeatability testing, comparison with an independent measurement system, and comparison with the dimensions of machined parts. The instrument is demonstrated to be capable of measurement of arbitrary three dimensional tool paths with near micron level accuracy.