Closing the Metrology – Process Loop in CNC Polishing

We have previously described our work combining industrial robots and CNC polishing machines in a Cell, where a robot can play the dual roles of automating manual operations on the CNC platform(s), and provide an effective smoothing capability in its own right. We have drawn attention to the complementary properties of standard CNC and robot platforms, in regard to speed, acceleration and precision of motion, and first resonant frequency. In this paper, we report on new work extending the scope of a Cell to incorporate a metrology station, and demonstrate how the transfer and alignment of the part, and acquisition of metrology data, can very effectively be automated. We have also demonstrated an automated ability to probe the part on-machine and then incorporate the probing data in the CNC control file. The purpose of this is to assure true registration of the CNC coordinate frame with that of the part. These advances constitute key developments towards our ultimate vision of a fully autonomous manufacturing cell. The distinguishing features are i) the iterative nature of the processes deployed, where details of each process-step depend on analysis of the output of the preceding step, and ii) the flexibility in manufacturing different parts.