MTO模式下基于随机不合格品返工的计划投产量决策

Decision of Materials Planning Quantities Based on Random Nonconforming Finished Goods and Rework under the MTO Mode

在订单式生产模式下,客户下单后明确提出产成品关于原材料、质量、数量及交货期等方面的要求。对于服装、皮革、文具等众多传统行业,人工操作的工序较多,生产过程中易产生不合格品,为了控制物料成本,须对不合格品进行返工,实际中,合格率和返工成功率具有随机不确定性。以满足产品需求数量及交货期为前提,以总生产成本最小化为目标,综合考虑初次投产成本,返工成本,过量合格品折价收益,再次投产成本以及废品收益等,构建最优计划投产量决策模型,证明总生产成本函数为凸函数,并对模型进行推导及讨论分析。算例表明,在可行域内,随着计划投产量的增加,总生产成本先下降后上升,合格品过量成本先上升后下降,合格品不足成本及总失配成本不断下降。在算例分析的基础上对各参数进行敏感性分析,通过图表揭示了各参数与最优计划投产量及总生产成本的变化规律。最后得出有关结论并提出成本控制策略。

Under the mode of MTO,customers clearly require the raw materials,quality,quantity,and delivery time about the finished products of the order.For traditional industries like clothing,leather and stationery,some operation processes are manual.It is easy to produce defective products and in order to control the cost of materials,the non-conforming products should be reworked.In reality,the passing rate and rework success rate are random.To meet the products＇ quantities,delivery time and to minimize the total production costs,taking initial production costs,rework costs,excess products income,later production costs and wasters earnings into consideration,the decision of materials planning quantities is modeled,discussed and analyzed.The total production cost function is proved as the convex one.The example shows that in the range of feasible solutions,with the increase of the materials planning quantities,the total production costs first decline then rise,the excessive products costs first rise then decline,and the lack products costs and total mismatch costs decline.Sensitivity analyses for each parameter is finished and the relations between the parameters and the optimal materials planning quantities and the responsive total production costs are revealed through figures.Finally,the conclusions are drawn and optimization strategies are proposed.