1
Toyota Production System and Lean Manufacturing
D. Jorge LeonTexas A&M University
TOYOTA PRODUCTION SYSTEM
The Toyota Production System was adopted by many Japanese companies in the aftermath of the 1973 oil shock
“Waste” Elimination Philosophy:
“.. Above all, one of our most important purposes was increased productivity and reduced cost. To achieve this purpose, we put our
emphasis on the notion of eliminating all kinds of unnecessary functions in the factories. Our approach has been to investigate one by one the causes of various "unnecessaries" in manufacturing operations
and to devise methods for their solution, often by trial and error ...”Taiicho Ohno, Former Vice President, Toyota Motor Corp., Former President, Japan Industrial Management
Association; Former Chairman, Toyoda Spinning and Weaving Co., Ltd.
2
PURPOSES OF JIT
Primary Purpose:Profit through cost reduction (or improvement of
Productivity)This is attained through WASTE elimination.
Other important purposes:Quantity control:
JIT, Kanban & Autonomation (visual control system)Quality control:
Autonomation, improvement by small groups, functional management
Respect for humanity :Flexible work force (adapt to demand changes), capitalize
workers ideas.
TYPES OF WASTE
Excessive production resources (primary waste):excessive workforceexcessive facilities
excessive inventoriesunnecessary capital investment
Overproduction (secondary waste - the WORST waste):
leads to
Excessive inventories (tertiary waste):extra jobs make overproduction invisible.
adds losses in opportunity cost
lead to
Unnecessary capital investment (fourth waste):adds facility depreciations and overhead cost
3
TO ACHIEVE THESE PUPOSES
7 Wastes EliminationJust-In-Time (JIT) Production
Kanban SystemProduction Smoothing
5SSetup Time Reduction
Machine Layout & Multi-function WorkerAutonomation (Visual Management)
4
Philosophy• Identification and elimination of waste is the central theme of a
lean manufacturing production system• Lean manufacturing is a dynamic and constantly improving
process dependent upon understanding and involvement by all employees
• Successful implementation requires that all employees must be trained to identify and eliminate waste from their work
• Waste exists in all work and at all levels in the organization
Identification and Elimination of Waste7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.
5
PhilosophyEffectiveness is the result of the integration of:
- Man- Method- Material- Machine At the worksite
• Waste exists in all work and at all levels in the organization
Identification and Elimination of Waste7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.
Seven Types of Waste7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.
Over-production
Wait time
Transportation
Processing
Inventory
Motion
Defects
6
Over-production Waste
DefinitionProducing more than neededProducing faster than needed
7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.
Over-production WasteCharacteristics:
• Inventory Stockpiles• Extra equipment/oversized equipment• Unbalanced Material Flow• Extra Part Storage racks• Extra Manpower• Batch Processing• Complex Inventory Management• Excessive Capacity/Investment• Additional Floor Space/Outside Storage• Hidden Problems• Excessive Obsolescence• Large Lot Sizes• Building Ahead
7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.
7
Causes:• Incapable Processes• Just in Case Reward System• Lack of Communication• Local Optimization• Automation in the Wrong Places• Cost Accounting Practices• Low Uptimes• Lack of Stable/Consitent Schedules
Over-production Waste7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.
Waiting Time Waste
DefinitionIdle Time That is Produced When Two Dependant Variables are
not Fully Synchronized.• Man Wait Time• Machine Wait Time
7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.
8
Characteristics:• Man Waiting for Machine• Machine/Materials Waiting for Man• Unbalanced Operations (Work)• Lack of Operator Concern for Equipment Breakdowns• Unplanned Equipment Downtime
Waiting Time Waste7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.
Waiting Time WasteCauses:
• Inconsistent Work Methods• Long Machine Change Over Time• Low Man/Machine Effectiveness• Lack of Proper Equipment/Materials
7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.
9
Transportation Waste
DefinitionAny Material Movement That Does Not Directly Support a Lean
Manufacturing System
7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.
Transportation WasteCharacteristics:
• Extra carts, fork lifts, dollies• Multiple Storage Locations• Extra Material Racks• Complex Inventory Management• Extra Facility Space• Incorrect Inventory Counts• Damaged Material
7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.
10
Transportation WasteCauses:
• Large Lot Processing• Unleveled Schedules• Lack of 5 S’s• Lack of Visual Controls• Improper Facility Layout• Large Buffers and In Process Kanbans
7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.
Processing WasteDefinition
Effort Which Adds No Value To a Product or Service. Enhancements which are Transparent to The Customers or Work Which Could Be Combined with Another Process.
7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.
11
Characteristics:• Process Bottlenecks• Lack of Clear Customer Specifications• Endless Refinement• Redundant Approvals• Extra Copies/Excessive Information
Processing Waste7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.
Causes:• Engineering Changes Without Processing Changes• Decision Making at Inappropriate Levels• Inefficient Policies and Procedures• Lack of Customer Input Concerning Requirements
Processing Waste7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.
12
Inventory Waste
DefinitionAny Supply in Excess of Process Requirements Necessary to
Produce Goods or Services Just in Time.
7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.
Inventory WasteCharacteristics:
• Extra Space on Receiving Docks• Material Between Processes• Stagnated Material Flow• LIFO instead of FIFO• Extensive Rework When Problems Surface• Long Lead Time for Engineering Changes• Additional Material Handling Resources (Men, Equipment,
Racks, Storage Space)
7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.
13
Inventory WasteCauses:
• Incapable Processes• Uncontrolled Bottleneck Processes• Incapable Suppliers• Long Change Over Times• Management Decisions• Local Optimization• Inaccurate Forcasting Systems
Wait TimeDefectsProcess
OverProduction
Inventory Level
7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.
Motion Waste
DefinitionAny Movement of People Which Does Not Contribute Added
Value To The Product or Service
7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.
14
Motion WasteCharacteristics:
• Looking for Tools• Excessive Reaching or Bending• Material Too Far Apart (Walk Time)• Equipment for Moving Parts• Extra “Busy” Movements While Waiting
7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.
Motion WasteCauses:
• Equipment, Office & Plant Layout• Lack of 5 S’s• Lack of Visual Controls• Inconsistent Work Methods (Standardized Work)• Large Batch Sizes
7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.
15
Rework or Correction Waste
DefinitionRepair of a Product or Service To Fulfill Customer requirements
7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.
Rework or Correction WasteCharacteristics:
• Extra Floor Space/Tools/Equipment• Extra Manpower To Inspect/Rework/Repair• Stockpiling Inventory• Complex Material Flow• Questionable Quality• Missed Shipments/Deliveries• Lower Profits Due To Scrap• Reactive Organization
7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.
16
Rework or Correction WasteCauses:
• Incapable Processes• Excessive Variation• Incapable Suppliers• Management Decisions• Insufficient Training• Inadequate Tools/Equipment• Poor Layouts/Unnecessary Handling• High Inventory Levels
7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.
Seven Types of Waste
Over-production
Wait time
Transportation
Processing
Inventory
Motion
Defects
7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.
17
Seven Types of Waste7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.7 Wastes, Applied Material’s, Lean Manufcaturing, Supplier Copy, 1999.