Specialized inspection problems in serial production systems

When defects are sometimes introduced in a serial manufacturing system, objectives such as minimization of total 'cost', maximization of yield, and minimization of undetected faulty units are all viable optimization objectives. We take a comprehensive look at the inspection problems in this setting and develop several new models for locating specialized inspection stations, stations which can only detect defects produced by specific operations. We consider the cases (1) when inspection/ rework stations are to be located, (2) when inspection stations are already located but their operating modes (rework or scrap) are to be determined, and (3) when both locations and operating modes are to be determined. We discuss exact and/or heuristic methods of solutions for these models, and present some computational experience.