Optimal Policy for Scheduled Production Run Time of Economic Production Quantity Model Involving Major Repair and Preventive Maintenance

This study introduces an integrated economic production quantity (EPQ) model incorporating preventive maintenance (PM) policies for an imperfect process with an increasing hazard rate. Determining the production run length hinges on either the scheduled production run time or the time to failure during each production run, whichever occurs first. Post-failure, the system undertakes major repair activities. After each PM, the system assumes either an imperfect or perfect state, with the probability of achieving a perfect PM dependent on the number of imperfect maintenance operations since the last renewal cycle. Mathematical formulas are derived to calculate the expected total cost. The discussion revolves around the scheduled production run time that minimizes total cost while increasing resource efficiency within the EPQ model. The study explores different scenarios, including the maintenance learning effect. Finally, the paper presents a numerical example of how PM, setup, rework, major repair and holding costs impact the system.