Sweep scan path planning for efficient freeform surface inspection on five-axis CMM

Abstract

Compared with the traditional 3-axis coordinate measuring machine (CMM), a 5-axis CMM equipped with the capability of continues sweep scanning can provide much denser data points while taking much shorter time. This paper presents an automatic sweep scan path planning system that generates a continuous sweep scanning path for the inspection of an arbitrary free-form surface using a 5-axis CMM with three translational axes and a rotary head with two very light rotary axes. The system strives to significantly improve the scanning efficiency by utilizing the superb kinematic advantages of the two rotary axes, which have very low moment of inertia, to cover a larger area, while tremendously reducing the speed and acceleration demand on the three translational axes which have much larger inertia. The path is generated from a mesh model of the freeform surface and an iterative approach is used to ensure that the stylus contacts the surface at an acceptable angle during the entire scan. Physical scanning experiments are performed and the test results show significant improvement in scanning efficiency by the proposed sweep scan path planning method when compared with some existing continuous scanning path planning approaches such as the standard isoparametric or zigzag method.