Dynamics modeling of CMM probing systems

The probing system dynamics is important for coordinate measuring machine (CMM) performance, particularly when probing in scanning mode. This is a typical situation e.g. in gear metrology, where the flanks are typically scanned. This may occur even without full awareness of the user, who may accept default values or choose with little understanding. This work presents a modelling of a contouring probe. The model is based on the characteristics of real probes; more specifically, continuous passive systems are considered, resulting essentially in second order 3D systems. The theoretical model is validated experimentally by scanning suitable surfaces exhibiting a range of slopes. The separation between static and dynamic effects is achieved by repeating the experiments at varying scanning speed, so that a same geometrical slope results in different temporal slopes – which the probing system dynamics is sensitive to. The model is oriented to define a good trade-off between the scanning speed and the measurement uncertainty.