Economical Lot-size Models With Inspection Errors And Space Constraint

With the rapid change of the operation environment and the more and moredetailed of the production process, the classical EOQ/EPQ mode become inadequateand inapplicable. In order to make the classical mode adapted to the modernenvironment and to be used again in a real manufacturing environment, theresearchers all in the world devoted themselves in the research, and have acquiredsome achievement.Classical EOQ models determines lot size merely considering ordering cost andstorage cost; classical EPQ models determines lot size merely considering setup costand storage cost depends on a perfect production process. But, both of the two model,their assumption are far away from real manufacturing environment, thus couldn’tprovide e scientific support to the decision making. So in this paper, EOQ/EPQ modelswere expended in order to satisfy manufacturing requirements were built and help tomake manufacturing decisions based on previous researches.At first, we began with the expended of the EOQ mode. The inspection processwas considered, once the products arrived, each will be inspected. However, theinspection process was not always perfect due to the TypeⅠand TypeⅡerrors. In thefirst error type, good items will get mis-identified as defectives and thus, result in thenecessity of producing additional items. The second error type will result in themis-identification of defectives as good items. The good products will be acceptedand the defectives will be sold at a cheaper price. A mode was built and the optimalorder polices were determined to achieve the minimum total cost. Then, theexpended of the EPQ model follows the same research method. A model withshortage and defectives was built and the defectives could be reworked and becameperfect. At last, a multi-products EPQ model with limited storage was built, the fuzzyand random t environment was considered in the models. An real case was used toconfirm each model.