JIT & Lean Production Systems 准时制与精益生产方式 Fang Aihua Wuhan University

Just-in-time Production Systems Lean Production Defined The Toyota Production System Lean Implementation Requirements Lean Services LP的定义 丰田生产系统 LP的实施条件 精益服务 Fang Aihua Wuhan University 2 2

Lean Production Defined 精益生产方式的定义 Fang Aihua Wuhan University

Lean Production 定义 LP: 利用低库存获得高产量的一整套活动. LP:努力消除浪费 LP:生产资源的时间编排(JIT) Lean Production can be defined as an integrated set of activities designed to achieve high-volume production using minimal inventories (raw materials, work in process, and finished goods) Lean Production also involves the elimination of waste in production effort Lean Production also involves the timing of production resources (i.e., parts arrive at the next workstation “just in time”) LP: 利用低库存获得高产量的一整套活动. LP:努力消除浪费 LP:生产资源的时间编排(JIT) 3

Here the customer starts the process, pulling an inventory item from Final Assembly… Pull System拉动系统 Customers Sub Fab Vendor Final Assembly Then sub-assembly work is pulled forward by that demand… The process continues throughout the entire production process and supply chain 4

Fang Aihua Wuhan University 起源问题 手工生产方式 大量生产方式 精细生产方式 法、德（19世纪） 奔驰公司 美国（20世纪上半叶） 福特公司 日本（20世纪下半叶） 丰田公司 Fang Aihua Wuhan University

精细生产方式 Lean Production 美麻省理工学院国际汽车项目组的研究人员给日本汽车工业的生产方式起的名称。 与大量生产方式相比， 只需一半的(人员、场地、投资) 产出质量更高、品种更多的产品 Fang Aihua Wuhan University

Some statistics from 1986 Framingham (GM) Toyota Takaoka 40.7 hours 130 defects 2 weeks Toyota Takaoka 16 hours 45 defects 2 hours A comparison of 1) assembly hours 2) defects / 100 cars 3) average inventory levels 方爱华 武汉大学经济与管理学院

The Japanese Approach to Productivity 日本人提高生产率的方法 （丰田公司精益生产方式） Fang Aihua Wuhan University

The Japanese Approach to Productivity 精益生产方式的产生背景 Goal of full employment in the post WWII period. Government (MITI) supported improvement of targeted industries. Imported technologies. Efforts concentrated on factory floor. Quality improvement focus 全民就业的目标 （实业建国） 政府扶持计划选定的产业 引进技术 （而非自主开发） 注重生产一线 持续质量改进 Fang Aihua Wuhan University 5 5

Fang Aihua Wuhan University Two Philosophies 核心理念 Elimination of waste Respect for people. 消除浪费 尊重人 Fang Aihua Wuhan University

Waste—Operations 生产中的七种浪费 (1) Waste from overproduction (2) Waste of waiting time (3) Transportation waste (4) Inventory waste (5) Processing waste (6) Waste of motion (7) Waste from product defects (1)过量生产的浪费 (2) 等待时间的浪费 (3) 运输的浪费 (4) 库存的浪费 (5) 工序的浪费 (6) 动作中的浪费 (7) 产品缺陷的浪费 Fang Aihua Wuhan University 6 6

The “Rocks in the Stream” Concept Boat (company operations) Water Level (Inventory) Rock (problem) Production Problems 方爱华 武汉大学经济与管理学院

Lowering the “Water” Level Inventory Reductions CRUNCH! Production Problems 方爱华 武汉大学经济与管理学院

Step Two - Deal with Exposed Problems Inventory Reductions Process Improvement of Production Problem Production Problems 方爱华 武汉大学经济与管理学院

Step Three - Continue the process Inventory Reductions Identification of new problem area Production Problems 方爱华 武汉大学经济与管理学院

What is Inventory in a Lean Production View? A potential form of waste (when value is not being added) A useful measurement to tell how well the system is working A useful tool to help identify critical uncertainties and production problems 方爱华 武汉大学经济与管理学院

The seven elements that address elimination of waste 消除浪费的七种方法 Focused factory networks Group technology Quality at source JIT production Uniform plant loading Kanban production control system Minimized setup times 集中工厂网络 成组技术 源头质量控制 JIT生产 均衡生产负荷 看板控制系统 最小化调整时间（换模） Fang Aihua Wuhan University

1. Focused Factory Networks 集中的工厂网络 小型专业化工厂 Small specialized plants Coordination System Integration 整合系统 Final Assembly Fang Aihua Wuhan University 7 7

2-Group Technology 成组技术 Departmental Specialization(Job shop) 部门专业化 Saw 锯 Grinder 磨 Saw Saw Saw Grinder Grinder Heat Treat 热处理 Lathe Lathe Lathe Press Press Press Lathe 车 Press 冲压 Fang Aihua Wuhan University 8 8

Fang Aihua Wuhan University Group Technology 成组技术 Group technology cells 成组技术加工单元 Saw 锯 Grinder 磨 Grinder 1 2 Lathe Press Saw Lathe Heat Treat 热处理 Grinder A B Lathe Press Saw Lathe Lathe 车 Press 冲压 Fang Aihua Wuhan University 9 9

3. Quality at the Source 源头质量控制 Do it right the first time and , when something goes wrong,stop the process or assembly line immediately. Self-inspection Automated inspection Line-stopping empowerment 自检 自动化质检设备 有权停止整个生产 线 Fang Aihua Wuhan University 10 10

Fang Aihua Wuhan University 4. JIT Production 准时制生产 Produce... ...what is needed... ...when it’s needed... ...NOTHING MORE! 只是在需要的时候生 产需要的数量 一个也不多 Fang Aihua Wuhan University 11 11

Definition of JIT JIT的含义 JIT is an integrated set of activities designed to achieve high-volume production using minimal inventories of raw materials,work in process, and finished goods. Parts arrive at the next workstation "just in time“ and are completed and move through the operation quickly. Fang Aihua Wuhan University

JIT is an integrated set of activities designed to... Achieve high-volume production using minimal inventories Raw materials Work in process, and Finished goods. 保持较低的库存实现大量生产 原材料 在制品 产成品 零部件正好及时到达下一个工位。 Parts arrive at the next workstation "just in time". Fang Aihua Wuhan University 3 3

JIT Classification JIT分类 Big JIT 大JIT （Lean Production 精益生产） Big JIT is the philosophy of operations management that seeks to eliminate waste in all aspects of a firm’s production activities: human relations, vendor relations, technology, and the management of materials and inventories. Little JIT 小JIT Little JIT focuses more narrowly on scheduling goods inventories and providing service resources where and when needed. Fang Aihua Wuhan University

Just-In-Time Production Management philosophy Pull system though the plant WHAT IT IS Attacks waste Exposes problems and bottlenecks Achieves streamlined production WHAT IT DOES Employee participation Industrial engineering/basics Continuing improvement Total quality control Small lot sizes WHAT IT REQUIRES Stable environment WHAT IT ASSUMES Fang Aihua Wuhan University 13 13

Just-In-Time Production 准时制生产 Management philosophy Pull system through the plant WHAT IT IS 一种管理哲学 一个“拉动”系统 JIT是什么？ Employee participation Industrial engineering/basics Continuing improvement Total quality control Small lot sizes WHAT IT REQUIRES 员工参与 工业工程 持续改进 TQC 小的生产批量 JIT的假设前提 Fang Aihua Wuhan University 13 13

Just-In-Time Production 准时制生产 向浪费宣战 揭露问题与瓶颈 实现流水生产 JIT做什么？ Attacks waste Exposes problems and bottlenecks Achieves streamlined production WHAT IT DOES 稳定的环境 JIT的假设 Stable environment WHAT IT ASSUMES Fang Aihua Wuhan University 13 13

Inventory Hides Problems 库存隐藏问题 Example: By identifying defective items from a vendor early in the production process the downstream work is saved Work in process queues (banks) Change orders Engineering design redundancies Vendor delinquencies Scrap Design backlogs Machine downtime Decision Inspection Paperwork backlog Example: By identifying defective work by employees upstream, the downstream work is saved 14

Fang Aihua Wuhan University 无库存生产方式 不要库存而进行生产 原材料库存 半成品库存 成品库存 Fang Aihua Wuhan University

Fang Aihua Wuhan University 建立无库存生产的制造单元 零件 一个一个地经过各个加工设备 一个入口存放处 一个出口存放处 工人 始终一个工人加工一个零件，依次经过所有设备 “将库房搬到厂房里” “使库房逐渐消失在厂房中” Fang Aihua Wuhan University

5. Uniform Plant Loading 均衡工厂负荷 / 计划的平准化 非单一的产品 稳定的产品组合 月份作业计划（日产量） This does not mean building a single product. We need to maintain a stable mix of products, and firm monthly schedules. Fang Aihua Wuhan University

Fang Aihua Wuhan University ——生产率=市场需求率(单位时间内的产量) ——生产频率=市场需求频率(单位时间内同种产品的生产次数) 减少批量 Fang Aihua Wuhan University

Minimizing Waste: Uniform Plant Loading (heijunka) Suppose we operate a production plant that produces a single product. The schedule of production for this product could be accomplished using either of the two plant loading schedules below. Not uniform Jan. Units Feb. Units Mar. Units Total 1,200 3,500 4,300 9,000 or Uniform Jan. Units Feb. Units Mar. Units Total 3,000 3,000 3,000 9,000 How does the uniform loading help save labor costs? 12

6. Kanban Production Control Systems 看板控制系统 Kanban: a signaling device to regulate JIT flow. 看板: 一种控制物流品种与数量的标识性的工具。 Fang Aihua Wuhan University

Kanban Production Control Systems This puts the system back were it was before the item was pulled Once the Production kanban is received, the Machine Center produces a unit to replace the one taken by the Assembly Line people in the first place Withdrawal kanban Storage Part A Storage Part A Machine Center Assembly Line Production kanban Material Flow Card (signal) Flow The process begins by the Assembly Line people pulling Part A from Storage 15

Calculating the Number of Kanbans Needed 计算看板数量 Setting up a kanban system requires determining the number of kanbans (or containers) needed. Each container represents the minimum production lot size. An accurate estimate of the lead time required to produce a container is key to determining how many kanbans are required. 确定看板(或容器)数量 每个容器代表最低的加工批量 关键是须要尽可能精确地估计生产一箱零件的时间 Fang Aihua Wuhan University 16 16

The Number of Kanban Card Sets, k 看板的数目 k = Number of kanban card sets d = Average number of units demanded over some time period L = lead time to replenish an order (same units of time as demand) S = Safety stock expressed as a percentage of demand during lead time C = Container size k = 看板数量 d = 平均需求量 L = lead time 提前期 S = 安全库存(用提前期中需求量的比例形式表示) C = 容器的大小 Fang Aihua Wuhan University 17 17

The Number of Kanban Card Sets, k Example A switch assembly is assembled in batches of 4 units from an “upstream” assembly area and delivered in a special container to a “downstream” control-panel assembly operation. The control-panel assembly area requires 5 switch assemblies per hour. The switch assembly area can produce a container of switch assemblies in 2 hours. Safety stock has been set at 10% of needed inventory. 批量=4 需求5个/小时 生产1筐需2小时 安全库存10% Fang Aihua Wuhan University 18 18

The Number of Kanban Card Sets, k Example Always round up! Fang Aihua Wuhan University 19 19

7. Minimized Setup Times 最小化调整转换时间 非常快地从一种产品的生产转化另一种产品的生产 What are the consequences of long setup times? A requirement for small-lot-size, mixed-model production? 换模时间过长的后果？ 小批、混合模式 Fang Aihua Wuhan University

Fang Aihua Wuhan University Respect for People 尊重人 Maintain level payrolls Cooperative employee unions Subcontractor networks Bottom-round management style Quality circles (Small group involvement activities) 维持稳定的工资 合作性的工会 分包商网络 现场管理（基层 委员会+小组） 质量小组 Fang Aihua Wuhan University 21 21

Toyota Production System’s Four Rules 四条规则 工作定义清晰 对外联系直接、清晰 路线简单直接 改进方法科学、只接受最低层指导 All work shall be highly specified as to content, sequence, timing, and outcome Every customer-supplier connection must be direct, and there must be an unambiguous yes- or-no way to send requests and receive responses The pathway for every product and service must be simple and direct Any improvement must be made in accordance with the scientific method, under the guidance of a teacher, at the lowest possible level in the organization 21

North American Modifications of JIT Can JIT work in North America? What are the cultural barriers to successful implementation? works Fang Aihua Wuhan University 22 22

Fang Aihua Wuhan University JIT Requirements JIT的前提条件 Fang Aihua Wuhan University

JIT Requirements: Design Flow Process 设计工艺流程 Link operations Balance workstation capacities Relayout for flow Emphasize preventive maintenance Reduce lot sizes Reduce setup/changeover time 连接操作 平衡工作地能力 保持物件流动 强调预修 减少批量规模 降低转换时间 Fang Aihua Wuhan University 23 23

JIT Requirements: Total Quality Control 全面质量管理 员工责任 质量统计方法 加强顺从/柔性 失误防范技术 自动化检测 Worker responsibility Measure SQC Enforce compliance Fail-safe methods Automatic inspection Fang Aihua Wuhan University 24 24

JIT Requirements: Stabilize Schedule 稳定的计划 Level schedule Underutilize capacity Establish freeze windows 均衡的计划 不超过生产能力 建立计划冻结的时间 区域 Fang Aihua Wuhan University 25 25

JIT Requirements: Kanban-Pull 看板拉动 Demand pull Backflush Reduce lot sizes 需求拉动 倒挤 -反工艺方向 减少生产批量规模 MIN：一批一件 Fang Aihua Wuhan University 26 26

JIT Requirements: Work with Vendors 与供应商合作 Reduce lead times Frequent deliveries Project usage requirements Quality expectations 缩短提前期 频繁供应 JIT项目应用的需求 质量预期 Fang Aihua Wuhan University 27 27

JIT Requirements: Reduce Inventory More 进一步减少库存 Look for other areas Stores Transit Carousels Conveyors 寻找其他区域 存储 运输 传送带 运输机 Fang Aihua Wuhan University 28 28

JIT Requirements: Improve Product Design 改进产品设计 Standard product configuration Standardize and reduce number of parts Process design with product design Quality expectations 产品配置标准化 零部件标准化与数量的减 少（简化） 结合产品设计的工艺过程 规划与设计 质量期望 Fang Aihua Wuhan University 29 29

Lean Implementation Requirements: Concurrently Solve Problems 并行解决问题 Root cause Solve permanently Team approach Line and specialist responsibility Continual education 根本原因 永久消除 团队方式 直线领导和专家共同负责 持续教育 29

Lean Implementation Requirements: Measure Performance 绩效评价 Emphasize improvement Track trends 强调改进 趋势跟踪 29

JIT Purchasing—Requirements 准时采购的条件 Reduced lot sizes Frequent and reliable delivery schedules Reduced and highly reliable lead times Consistently high quality levels for purchased materials １ 减小批量 ２ 频繁而可靠的交货 ３ 提前期压缩并且高度可靠。 ４ 保持一贯的采购物资的高质量。 方爱华 武汉大学经济与管理学院 11 11

JIT Purchasing—Suppliers 准时采购——供应商 Fewer, nearby suppliers Repeat business Support suppliers’ competitiveness Clusters of remote suppliers Limit competitive bidding to new parts Resist vertical integration Encourage suppliers to implement JIT purchasing 少量、近距离 重复业务 支撑供应商竞争力 使距离较远的供应商尽可能靠近 投标竞争仅限于新的零部件 反对垂直一体化 鼓励供应商也实施准时采购 方爱华 武汉大学经济与管理学院 12 12

JIT Purchasing—Quantities 准时采购——数量 Steady output rate (a desirable prerequisite) Frequent deliveries in small lot quantities Long-term contract agreements with minimal release paperwork Deliver quantities variable from release to release but fixed for whole contract term 稳定的产出率 频繁的小批量送货 长期合同、减少日常文书工作 每次交货数量可变，但整个合同期的数量固定 方爱华 武汉大学经济与管理学院 13 13

JIT Purchasing--Quantities (Ctd) 准时采购——数量 Little or no permissible overage or underage of receipts Suppliers encouraged to package in exact quantities Suppliers encouraged to reduce their production lot sizes (or store unreleased material) 很少或不容许超量送货或送货不足 鼓励供应商按照准确数量包装 鼓励供应商降低生产批量（或存储未发送的原材料） 方爱华 武汉大学经济与管理学院 14 14

JIT Purchasing—Quality 准时采购——质量 Minimal product specifications imposed on supplier Help suppliers to meet quality requirements Close relationships between buyers' and suppliers' quality assurance people Suppliers encouraged to use process control charts instead of lot sampling inspection 很少强迫供应商提供产品说明书 帮助供应商达到质量要求 与供应商的质量保证人员保持密切关系 鼓励供应商使用过程控制图代替抽样检验 方爱华 武汉大学经济与管理学院 15 15

JIT Purchasing—Shipping 准时采购——装运 制订国内运输计划 控制运输的进度： 自有或签约的装运公司 仓储合同 使用拖车进行货物运输与存储 （而非通用工具） Scheduling of inbound freight Gain control by use of company-owned or contract shipping contract warehousing trailers for freight consolidation/storage 方爱华 武汉大学经济与管理学院 16 16

Fang Aihua Wuhan University JIT in Services JIT在服务业的应用 （10项建议） Fang Aihua Wuhan University

JIT in Services (Examples) Organize Problem- Solving Groups Upgrade Housekeeping Upgrade Quality Clarify Process Flows Revise Equipment and Process Technologies 建立问题协调小 组 改进工作环境 改进质量 使业务流程清晰 化 修理设备、完善 工艺技术 Fang Aihua Wuhan University 30 30

JIT in Services (Examples) 均衡设备负荷 消除不必要的活 动 物理结构的重组 引进需求拉动计 划 发展供应商网络 Level the Facility Load Eliminate Unnecessary Activities Reorganize Physical Configuration Introduce Demand-Pull Scheduling Develop Supplier Networks Fang Aihua Wuhan University 31 31