Design of an integrated quality-assurance strategy in production systems

International audienceHigh-quality of products is a critical issue for manufacturers to maintain their competitiveness in global markets. For this reason, more attention has been paid by operations managers and academics about the design of quality-assurance strategies, acceptance sampling plans and inspection allocation problems. In the last decades, international research has studied and introduced several models and approaches to investigate these issues. The purpose of this paper is to provide a new methodology for designing and selecting correct integrated quality-assurance strategies, defining cost models for acceptance policies and inspection station configurations. Generally, high-quality of items is guaranteed avoiding defects, mainly caused by nonconforming components, due to instantaneous and standard infant mortality. Thus, the optimal acceptance policy is defined in order to reduce the instantaneous infant mortality defects. A close formulation has been introduced to determine easily and quickly the optimal percentage of checked items. Furthermore, the more convenient inspection station configuration is determined in order to minimize the expected total cost, composed by testing, inspection and penalty cost elements. The innovative concept of defect rate as an inspection time variable dependent has been introduced. The impact of different economic and survival parameters on designing inspection policies is also investigated. Finally, a real case study demonstrates the applicability of this methodology in real production systems and several considerations are reported about the future researches, that the authors will carry out