ROBOTIC CIRCUIT BOARD TESTING USING FINE POSITIONERS WITH FIBER-OPTIC SENSING.

Electrical testing of high-density circuit boards is becoming an increasingly important robotic application. As wiring complexities and board sizes grow larger, speed and precision limitations make it difficult to apply conventional robots to this problem. Accurate positioning tables with dimensional stabilities derived from granite blocks and iron castings become prohibitively expensive. These limitations can be overcome, however, by a combination of endpoint sensing and fine positioning. We have developed a robotic system with redundant coarse and fine degrees of freedom and fiber optic sensing for the probing of very narrow circuit board traces. System elements include a two-armed cartesian robot programmed in AML carrying two planar fine positioners (FPs) equipped with differential fiber optic and electrical probes.