Economic order quantity model for items with imperfect quality, different holding costs, and learning effects: A note

In this note, we present the optimal lot sizes for an item with imperfect quality based on Salameh and Jaber [Salameh, M. K., & Jaber, M. Y. (2000). Economic production quantity model for items with imperfect quality. International Journal of Production Economics, 64, 59–64], Maddah and Jaber [Maddah, B., & Jaber, M. Y. (2008). Economic order quantity for items with imperfect quality: Revisited. International Journal of Production Economics, 112, 808–815], and Jaber et al. [Jaber, M. Y., Goyal, S. K., & Imran, M. (2008). Economic production quantity for items with imperfect quality subjected to learning effects. International Journal of Production Economics, 115, 143–150] when different holding costs for the good and defective items are considered. When there is no learning effects, the results show that the lot size with different holding costs for good and defective items increases when the percentage of defective increases, as one would expect in the real manufacturing environment. When there is learning effects, the lot size with different holding costs for the good and defective items is more than the one with same holding costs for the good and defective items. However, as the learning takes place in the system, the difference between the lot sizes with and without different holding costs for the good and defective items disappears.