We encountered an issue with a purlin line running multi-axis. On a particular part on queue initilization the controller would make its scrap part, punch the first four holes of the good part, and then stop punching altogether, making shear only parts until the line halted.

This issue was tracked down to two presses, with apposing axes, becoming dead locked on finding targets that they could each punch. The issue was caused by one press having two missmatched indicators. Presses A's Axis indicated that it was processing a Y-Axis Target but Press A's queue did not reflect it, which put it in an loop looking for a target. The loop did not end until Halting the line. Press B entered a loop waiting for Press A's axis to finish its target, which it never did, until the line halted. The Line halted when it ran out of parts, all with missing holes.

The cause of the missmatched indicators was found and fixed, however, it is not clear why we have not seen this until now. It seems like it should have been a more prevelent problem.