2 Lean LogicLean is based on the logic that nothing will be produced until it is needed.A sale pulls a replacement from the last position in the system.This triggers an order to the factory production line.Each upstream station then pulls from the next station further upstream.
4 Toyota Production System Elimination of WasteRespect for PeopleWaste from overproductionWaste of waiting timeTransportation wasteInventory wasteProcessing wasteWaste of motionWaste from product defectsLifetime employment for permanent positionsMaintain level payrolls even when business conditions deteriorateCompany unionsBonusesView workers as assets
5 Principles of Lean Supply Chain Design Lean LayoutsGroup technologyQuality at the sourceJIT productionLean Production SchedulesUniform plant loadingKanban production control systemLean Supply ChainsSpecialized plantsWork with suppliersBuilding a lean supply chain
6 Lean ConceptsGroup technology: a philosophy in which similar parts are grouped into familiesThe processes required to make the parts are arranged in a manufacturing cell.Eliminates movement and queue time between operations, reduces inventory, and reduces employees.Instead of specialized workcentersGroup technology manufacturing cells
7 Quality at the SourceQuality at the source: do it right the first time and if something goes wrong, stop the process immediatelyWorkers are personally responsible for the quality of their output.Workers become their own inspectors.Workers are empowered to do their own maintenance.
8 Just-in-Time (JIT) Production JIT production: producing what is needed when needed and nothing moreAnything over the minimum is waste.Typically applied to repetitive manufacturing.Ideal lot size is one.Vendors ship several times a day.JIT exposes problems otherwise hidden by inventory.
10 Kanban Systems Kanban means “sign” or “instruction card” in Japanese Worker takes the first part A from a full container.Worker takes the withdrawal Kanban from the container and takes the card to the machine center storage area.In machine center, worker finds a container of part A.Worker removes the production Kanban and replaces it with the withdrawal Kanban.The freed production Kanban is placed on a rack by the machine center, which authorizes the production of another lot of material.The cards on the rack become the dispatch list for the machine center.Kanban means “sign” or “instruction card” in JapaneseCards or containers are usedMake up the Kanban pull system
11 Other Kanban Approaches Kanban squaresMarked spaces on the floor to identify where material should be storedContainer systemThe container is used as a signal deviceColored golf ballsAppropriate golf ball signals production
12 Kanban SystemKanban system – A production control approach that uses containers, cards, or visual cues to control the production and movement of goods through the supply chain.Key characteristics:Uses simple signaling mechanisms to indicate when specific items should be produced or moved.Can be used to synchronize activities either within a plant or between different supply chain partners.Are not considered planning tools, but rather control mechanisms that are designed to pull parts or goods through the supply chain based on downstream demand.
13 Kanban SystemTwo-card kanban system – Uses one card to control production and another card to control movement of materials.
15 Release of Finished Materials from Work Center B Figure 13.6
16 Pulling of Raw Materials into Production at Work Center B Figure 13.7
17 Removal of Finished Materials from Work Center A Figure 13.8
18 Two-card System Summary A downstream system station pulls finished material out of work center B.Work center B pulls raw material into production.Demand for more raw material in work center B pulls finished material out of work center A.
19 Pull SystemPull system – A production system in which actual downstream demand sets off a chain of events that pulls material through the various process steps.A kanban system is also called a pull system.
20 Value Stream MappingValue stream mapping: a special type of flowcharting tool used to analyze where value is or is not being added as material flows through a processRequires a full understanding of the business, including production processesValue Stream MappingA common “lean systems” toolExamines entire value stream for waste
21 Manufacturing Process Map: Current State of a Process (Exhibit 14.8)
25 Lean WasteLean Waste – Any activity that does not add value to the good or service in the eyes of the consumer.Called “muda” in JapaneseIdentification of lean wastes began with Taiichi Ohno, a Toyota engineer.
27 Lean Perspective on Inventory Triangles represent inventory between work centers A, B, and C.The buildup of inventory hides problems (at a cost) that may occur.Figure 13.2
28 Lean Perspective on Inventory After a Lean transformation, wasted movement and space are eliminated and work centers are moved closer together.Inventory levels are reduced dramatically and work centers make only what is needed when it is needed.Figure 13.3
29 Lean Perspective on Inventory Process of reducing inventory leads to reduction of the other “wastes” and exposes problems in order of severity (‘water and rocks’ analogy)Figure 13.4