Accurate alignment of laminate materials using sensor-based robot techniques

A system and strategy is described here to fabricate circuit boards requiring alignment accuracies of 7.5 μm using existing automation equipment with enhancements and typical manufacturing line fixtures. The system, configured as a pilot workcell, consisted of an IBM 7576 coarse positioning robot, a fine positioning manipulator, an optical sensing system and a unique bracing method to reduce environmental disturbances. The strategy was to use a coarse/fine placement technique with sensing to align, stack and bond individual test laminates with patterns of 100 μm holes. The results showed that pairs of holes were consistently aligned to 2-5 μm which surpasses the 7.5 μm manufacturing requirement.