Production-maintenance policy in a deteriorating production system

Abstract

The economic manufacturing quantity model has been analyzed under various conditions. But most of the associated research have assumed implicitely that the production process always produces items of acceptable quality. However, quality of the product is not always perfect, and is usually dependent on the state of the production process. This study is concerned with the production-maintenance policy for the deteriorating production system which can go out of control while producing items. So the thesis is categorized into three parts according to the type of process deterioration and the policy of compensation for defective items passed to the customer: First, the problem of the joint determination of production cycle and process inspection intervals is treated considering the difference between reworking cost before sale and warranty cost after sale. A case of equally spaced inspection intervals is solved using an approximation to the cost function. Second, the problem of production-maintenance policy is considered when discount contract is offered as a compensation for defective items, assuming successive inspections to be of equal intervals apart. Finally, the problem of the determination of economic manufacturing quantity is considered assuming that deterioration of the production process follows a two-state Markov chain during production of the lot, with a transition occuring with each unit produced.