Machine vision system for the industrial quality control of printed circuit boards

In this paper we present an automatic system for the on-line quality control of printed circuit boards. A line-scan camera permits the acquisition of a 550 mm wide image with a resolution up to 70 microns/pixel. The system detects the following type of errors: cuts and short circuits in tracks, stains, ink excess or faults, pores, omissions, "bites" and track narrowing. The input for the system are just the Gerber data files corresponding to the circuit to be analyzed. All the tolerances and precision factors can be modified directly from the user-friendly interface. For each analyzed board, the type of error detected and its location inside the circuit are indicated in the interface. For each set of analyzed circuits the system provides information for statistical control of the results.