Firstly an overview of the potential impact on work-in-process （WIP） and lead time is provided when transfer lot sizes are undifferentiated from processing lot sizes. Simple performance examples are compared to thos...Firstly an overview of the potential impact on work-in-process （WIP） and lead time is provided when transfer lot sizes are undifferentiated from processing lot sizes. Simple performance examples are compared to those from a shop with one-piece transfer lots. Next, a mathematical programming model for minimizing lead time in the mixed-model job shop is presented, in which one-piece transfer lots are used. Key factors affecting lead time are found by analyzing the sum of the longest setup time of individual items among the shared processes （SLST） and the longest processing time of individual items among processes （LPT）. And lead time can be minimized by cutting down the SLST and LPT. Reduction of the SLST is described as a traveling salesman problem （TSP）, and the minimum of the SLST is solved through job shop scheduling. Removing the bottleneck and leveling the production line optimize the LPT. If the number of items produced is small, the routings are relatively short, and items and facilities are changed infrequently, the optimal schedule will remain valid. Finally a brief example serves to illustrate the method.展开更多
针对机械式穴播器装配线上在制品(Work In Process,WIP)主要依靠管理人员经验进行定性控制的问题,采用多点控制的方法对装配线上在制品进行定量优化。首先运用约束理论(Theory Of Constraint,TOC)结合推、拉两种生产方式对装配线进行分...针对机械式穴播器装配线上在制品(Work In Process,WIP)主要依靠管理人员经验进行定性控制的问题,采用多点控制的方法对装配线上在制品进行定量优化。首先运用约束理论(Theory Of Constraint,TOC)结合推、拉两种生产方式对装配线进行分段研究,在分段节点设立瓶颈缓冲区、并联缓冲区和风险缓冲区;然后根据工位故障持续时间与物料消耗速度计算出缓冲区最优容量,得出机械式穴播器装配线在制品多点控制优化方案。通过对某企业机械式穴播器装配系统进行Flex Sim仿真,验证了方案的可行性。展开更多
针对当前在制品库存控制研究较少考虑系统瓶颈的现状,从最优化生产技术(Optimized Production Technology,OPT)的思想出发,在辨别出系统瓶颈的基础上,设计以瓶颈为中心驱动的推、拉结合(Push&Pull)的生产控制方式,以有效减少整个系...针对当前在制品库存控制研究较少考虑系统瓶颈的现状,从最优化生产技术(Optimized Production Technology,OPT)的思想出发,在辨别出系统瓶颈的基础上,设计以瓶颈为中心驱动的推、拉结合(Push&Pull)的生产控制方式,以有效减少整个系统的在制品库存;建立面向瓶颈的在制品库存前-反馈集成控制(B-WFFIC)模型,稳定并减少瓶颈工序前的在制品库存;最后通过实例应用和仿真验证取得了较优的结果。展开更多
基金This project is supported by National Natural Science Foundation of China (No.70372062, No.70572044)Program for New Century Excellent Talents in University of China (No.NCET-04-0240).
文摘Firstly an overview of the potential impact on work-in-process （WIP） and lead time is provided when transfer lot sizes are undifferentiated from processing lot sizes. Simple performance examples are compared to those from a shop with one-piece transfer lots. Next, a mathematical programming model for minimizing lead time in the mixed-model job shop is presented, in which one-piece transfer lots are used. Key factors affecting lead time are found by analyzing the sum of the longest setup time of individual items among the shared processes （SLST） and the longest processing time of individual items among processes （LPT）. And lead time can be minimized by cutting down the SLST and LPT. Reduction of the SLST is described as a traveling salesman problem （TSP）, and the minimum of the SLST is solved through job shop scheduling. Removing the bottleneck and leveling the production line optimize the LPT. If the number of items produced is small, the routings are relatively short, and items and facilities are changed infrequently, the optimal schedule will remain valid. Finally a brief example serves to illustrate the method.
文摘针对机械式穴播器装配线上在制品(Work In Process,WIP)主要依靠管理人员经验进行定性控制的问题,采用多点控制的方法对装配线上在制品进行定量优化。首先运用约束理论(Theory Of Constraint,TOC)结合推、拉两种生产方式对装配线进行分段研究,在分段节点设立瓶颈缓冲区、并联缓冲区和风险缓冲区;然后根据工位故障持续时间与物料消耗速度计算出缓冲区最优容量,得出机械式穴播器装配线在制品多点控制优化方案。通过对某企业机械式穴播器装配系统进行Flex Sim仿真,验证了方案的可行性。
文摘针对当前在制品库存控制研究较少考虑系统瓶颈的现状,从最优化生产技术(Optimized Production Technology,OPT)的思想出发,在辨别出系统瓶颈的基础上,设计以瓶颈为中心驱动的推、拉结合(Push&Pull)的生产控制方式,以有效减少整个系统的在制品库存;建立面向瓶颈的在制品库存前-反馈集成控制(B-WFFIC)模型,稳定并减少瓶颈工序前的在制品库存;最后通过实例应用和仿真验证取得了较优的结果。
