THE STUDY OF A DETERIORATING MANUFACTURING SYSTEM USING SIMULATION AND RESPONSE METHODOLOGY

A deteriorating production system consisting of two parallel machines with the production dependent failure rates of the machine is investigated in this paper. The machines produce one type of final products. The demand rate for the final commodity is constant and unmet demand is backlogged. The goal of the control problem is to find the production rates of both machines so as to minimize a long term average expected cost which penalizes both the presence of waiting customers and the inventory. In the proposed model, the production rate of the first machine is higher than the production rate of the second machine. The failure rate of the first machine which is the main machine depends on its production rate. The failure rate of the second machine is constant. The proposed model is based on a Markov decision process, and the stochastic dynamic programming method is used to obtain the optimality conditions. Control policy parameters are obtained by combining analytical modelling, simulation experiments and response surface methodology. Sensitivity analyses of the optimal results with respect to the system parameters are also examined to illustrate the importance and effectiveness of the proposed methodology. The usefulness of the proposed approach is outlined for more complex situations where the system must deal with non-exponential failure and multiple machines.