Abstract: An economic production quantity (EPQ) model based on imperfect production and conditional maintenance is constructed. Weibull distribution curve width is used to describe the deterioration of reliability and the renewal theorem adopted to solve the minimum of the expected average total cost of the model. Two models are studied considering the Weibull distribution curve width as geometric progression and arithmetic progression respectively. It indicates that the expected average cost of first model is greater than that of the model with no deterioration but the threshold, and its corresponding value, the optimal quantity and maintenance times are all lower than those of the model with no deterioration. The expected average cost and threshold of second model is lower than that of the model with no deterioration, but the optimal quantity and maintenance times are greater than those of the model with no deterioration. The study also finds that ratio and tolerance are the most important factors affecting expected average cost, while demand is the most important factor affecting the reliability threshold of conditional maintenance. The relevant study can provide managers with decision reference.

Key words: imperfect production, conditional maintenance, economic production quantity, deterioration of reliability