Integrated Maintenance-Quality strategies with reworking activities

This paper deals with integrated models joining Non Quality effects and preventive maintenance (PM) policies. We consider a manufacturing system composed of a single machine subject to random failures and producing conforming and non conforming products. In order to decrease the random failure rate of our manufacturing system, we apply a preventive maintenance policy with minimal repair and non-negligible durations of maintenance actions. Our objective is to determine an optimal integrated maintenance-quality strategy taking into consideration the decreased quality of output products and the economic impact of reworking activities. In fact, we developed two different strategies: For the first strategy, we propose reworking activities for all non conforming products in order to improve their quality condition and to sell all batches at the best price Pmax. The aim of this strategy is to found the optimal number of batches produced and reworked N* before each preventive maintenance action, maximizing the total net profit per time unit PT1. For the second strategy, the same problem is studied but for a finite horizon. Two mathematical models are developed in order to find the optimal value of the decision variable N* for both strategies. Numerical examples are presented in order to illustrate proposed models and a sensitivity study is developed to evaluate the influence of the variation of models' parameters.