Abstract: An apparatus for inspecting an SMT printed circuit board includes an inspection head mounted to an X-Y table, for directed movement above the SMT printed circuit board which is to be inspected. The inspection head is caused to proceed to successive viewing fields along the surface of the SMT printed circuit board, for inspection by a series of cameras disposed within the inspection head together with appropriate lighting which is selected according to the inspection which is to be performed. Prior to soldering, it is determined whether each of the series of components to be placed on the printed circuit board were deposited as scheduled, and whether the deposited components were correctly positioned. Following the soldering procedure, it is again determined whether each component remains present on the board, and in its correct position, and steps are taken to inspect the solder fillets, and to inspect for any solder bridges.

Abstract: A compensating system for insepcting potentially warped printed circuit boards provides the insepction head of a printed circuit board inspection apparatus with a compensating device which is capable of detecting deviations in the printed circuit board which depart from a reference standard, for use in accurately compensating for such deviations during the board inspection procedure. An appropriate source (including ultrasonic, laser and directed light sources) is used to direct emissions toward the surface of a printed circuit board to be inspected. Detected reflections are then used to provide information useful in determining deviations of the surface of the printed circuit board from the reference standard, to adjust the anticipated locations for any component features, connecting leads or pins which are to be inspected within the subject viewing field.