An EOQ model for imperfect quality products with partial backlogging – a comparative study

The purpose of this paper is to compare two deterministic inventory models of imperfect quality items where the position of occurrence of shortages makes them distinct. In model‐I, the shortage occurs at the beginning of the cycle, where as, it occurs at the end of the cycle in model‐II. In both the models, backlogging is considered. We have studied two cases on the basis of backlogging which are: A) partially backlogging; B) completely backlogging. In Case‐A, we assume that a certain percentage of unsatisfied demand which occurs during shortage period is back‐ordered and in Case‐B, complete backlogging of the unsatisfied demand is taken into consideration. Using optimisation techniques, we have analysed both the models and obtained the optimal lot sizes and optimal shortage periods in both the models. Comparisons, with respect to partial backlogging and complete backlogging, are made between these models with the help of two numerical examples, which are also used to illustrate the models and the solution procedures. Graphical illustrations of these two models are also given. In addition, sensitivity analysis of the optimal solutions of Case‐A of model‐I and model‐II are also given.