企业运营管理约束理论.ppt

Theory of Constraints 约束理论 Not all resources are used evenly Concentrate on the” bottleneck” resource Synchronize flow through the bottleneck Use process and transfer batch sizes to move product through facility 不是所有的资源都会被使用 集中精力解决瓶颈问题 使流程与瓶颈同步 让流程与批量服务于产品流动 Copyright 2009 John Wiley Sons, Inc. 17-* * Fang Aihua Wuhan University 17 Saving Time有效的改进对策:节约时间 Bottleneck Nonbottleneck What are the consequences of saving time at each process? * Fang Aihua Wuhan University 18 Drum, Buffer, Rope鼓、缓冲器、绳子 A B C D E F 鼓(Drum) 缓冲器 (Inventory Buffer) Communication 绳子(rope) Market 市场 Copyright 2009 John Wiley Sons, Inc. 17-* DBR(Drum-Buffer-Rope)鼓-缓冲器-绳子 Drum 鼓 – 设定鼓点(生产节奏) Bottleneck, beating to set the pace of production for the rest of the system Buffer 缓冲器 – 瓶颈设备前设置库存 Inventory placed in front of the bottleneck to ensure it is always kept busy Determines output or throughput of the system Rope 绳子—前向调度 Communication signal; tells processes upstream when they should begin production TOC Scheduling ProcedureTOC排序规则 Identify bottleneck Schedule job first whose lead time to bottleneck is less than or equal to bottleneck processing time Forward schedule bottleneck machine Backward schedule other machines to sustain bottleneck schedule Transfer in batch sizes smaller than process batch size 识别瓶颈 先排到瓶颈的提前期等于或小于瓶颈工序作业时间的工序 顺排瓶颈设备的各项工作 逆排其他设备的工作 搬运批量小于加工批量 Copyright 2009 John Wiley Sons, Inc. 17-* * Fang Aihua Wuhan University TOC例题(Russell) Copyright 2009 John Wiley Sons, Inc. 17-* TOC例题(Russell)--3台设备3个零件 B A C D B1 1 5 B2 2 3 B3 1 7 C1 3 2 C2 1 10 C3 2 15 D1 3 10 D2 2 8 D3 3 5 Operation j of item i performed at machine center k takes l minutes to process Item i Key: i ij k l 产品结构: A=B+C+D 生产工序:各有3道序 设备: 三种加工中心各一台(编号1,2,3) 设备调整准备时间:60分钟 Copyright 2009 John Wiley Sons, Inc. 17-* 设备负荷表(识别瓶颈设备) 设备1 设备2 设备3 工序名 作业时间 工序名 作业时间 工序名 作业时间 零件B B1 B3 5 7 B2 3 零件C C2 10 C3 15 C1 2 零件D D2 8 D1 D3 10 5 Sum 22 26* 17 需求量 Demand = 100 A’s 设备准备时间Machine