Quality and production control in multiple-product unreliable manufacturing system

Abstract

This paper seeks to address the joint production and quality specification control problem in multiple-product unreliable manufacturing systems. In this context, the decision maker should make the best compromise between production and quality policy to adopt so as to maximize the long term average per unit time profit. This compromise is required given that the policies governing the production and quality decision making can be conflicting. In fact, tight process specifications will generally lead to products with good quality and higher market values, but at the same time associated with higher rate of non-conforming parts rejection leading to higher non quality costs and lower plant productivity. Moreover, one should consider the unreliability of the manufacturing system. To hedge against future capacity shortages caused by machine failures, the decision maker should adopt an adequate production policy in order to meet customer demand and minimize the incurred total cost. The paper tackle the problem in a dynamic stochastic context with a combined approach, based on optimal control theory, simulation modeling and response surface methodology. The obtained results are promising and show that the profit under the considered joint policy is improved up to 7% compared with dissociated production and quality strategies.