Effect of rework, rejects and inspection on lot size with work-in-process inventory
本文针对传统经济批量模型假设生产过程完美无缺的缺陷，将不完美生产和批量检验纳入考量，建立了一个更现实的数学模型来计算最优批量大小和总成本，并评估了返工、废品和检验对在制品库存的显著影响。
The economic order quantity and economic production quantity models are the most commonly used inventory models in production environments for the calculation of optimum lot size. However, these models are based on the unrealistic assumption that every process produces good quality products every time. Moreover, the impact of inspection is neglected in all extended inventory control models involving work in process inventory. By taking both imperfect production and lot size inspection into consideration, this paper presents a more realistic approach for the modelling of optimum lot size and total cost with a focus on the work in process inventory. A mathematical model is derived for optimum lot size based on the minimisation of the average cost. Our approach incorporates the effect of rework, rejects and inspection on work in process inventory. The significant effect of imperfect production and inspection on optimum lot size is evaluated via numerical examples. In comparison to existing models, the proposed model is a more generalised and flexible form of inventory model for independent demands.