Document Type : Article
Department of Industrial Engineering, Faculty of Engineering, University of Qom, Qom, Iran
Department of Industrial Engineering, Faculty of Mechanical Engineering, Jundi-Shapur University of Technology, Dezful, Iran
Due to the imperfection of processes, the quality of some products may be unsatisfactory. Moreover, equipment failure can stop production for a while. Therefore, integrating the triple concepts of quality, maintenance, and inventory control has attracted attention. Triple concepts are the constituents of the pre-sale costs. Selling price and warranty are generally considered to maintain market share and maximize the producer's profit. Quality and maintenance in production should be considered to reduce the post-sale costs of the warranty. Despite interactions, integrating warranty with triple concepts has been neglected. We integrate the quadruple concepts in a bi-objective model to maximize the profit and minimize the pre-sale and post-sale costs under the free minimal repair warranty policy. A non-central chi-square (NCS) control chart monitors the mean and variance, simultaneously. The technology level is also considered for increasing product quality and reducing failures during the warranty period. Due to its high complexity, the model is solved by the particle swarm optimization algorithm. The proposed model is applied through a numerical example and three comparative studies. The results indicate the better performance of the NCS chart, the superiority of bi-objective optimization versus single-objective optimization, and the importance of integrating presale and postsale costs.