Economic-order-type inventory models for non-instantaneous deteriorating items and backlogging

This paper is concerned with finding the optimal economic order quantity for the basic (EOQ) inventory model with backlogging in the presence of non-instantaneous deterioration. It is shown that the optimal EOQ is a threshold policy. That is, (i) if the time at which deterioration begins in the non-instantaneous deterioration model is greater than or equal to the time at which backlogging begins in the basic (EOQ) model, then the optimal policy is determined by the parameters of the basic (EOQ) model, else (ii) the optimal policy corresponds to the unique critical point of the objective function for the model with non-instantaneous deterioration. An approach for determining this policy is proposed. This approach is simple and easy to implement. Moreover, it does not suffer from the shortcomings of existing approaches in the literature. A numerical example is presented for illustration