Lean Manufacturing & Just-in-Time "The most dangerous kind of waste is the waste we do not...
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Transcript of Lean Manufacturing & Just-in-Time "The most dangerous kind of waste is the waste we do not...
Lean Manufacturing & Just-in-Time
"The most dangerous kind of waste is the waste we do not recognize." -
Shigeo Shingo
Material Flow
Information Flow
FGI
CustomerRaw
MaterialSupplier
FinalAssembly
PUSH
FGI
CustomerRaw
MaterialSupplier
FinalAssembly
PULL
Reducing Waste: Push versus Pull System
Push System Every worker maximizes own output, making as
many products as possible Pros and cons:
Focuses on keeping individual operators and workstations busy rather than efficient use of materials
Volumes of defective work may be produced Throughput time will increase as work-in-process
increases (Little’s Law) Line bottlenecks and inventories of unfinished products
will occur Hard to respond to special orders and order changes due
to long throughput time
Pull System Production line is controlled by the last
operation, Kanban cards control WIP Pros and cons
Controls maximum WIP and eliminates WIP accumulating at bottlenecks
Keeps materials busy, not operators. Operators work only when there is a signal to produce.
If a problem arises, there is no slack in the system Throughput time and WIP are decreased, faster
reaction to defects and less opportunity to create defects
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• Management philosophy• “Pull” system though the plant
WHAT IT IS
• Employee participation• Industrial engineering/basics• Continuing improvement• Total quality control• Small lot sizes
WHAT IT REQUIRES
• Attacks waste• Exposes problems and bottlenecks• Achieves streamlined production
WHAT IT DOES
• Stable environment
WHAT IT ASSUMES
Features of Lean Production
Kaizen
A Little History! Ford: Design for manufacturing
Start with an article that suits and then study to find some way of eliminating the entirely useless parts. This applies to everything— a shoe, a dress, a house, a piece of machinery, a railroad, a steamship, an airplane. As we cut out useless parts and simplify necessary ones, we also cut down the cost of making. ...But also it is to be remembered that all the parts are designed so that they can be most easily made."
A Little History!
Ohno – put ideas into practice systematically “When bombarded with questions from our group on
what inspired his thinking, Ohno just laughed and said he learned it all from Henry Ford's book."
A system that continually searches for and eliminates waste throughout the value chain.
Views every enterprise activity as an operation and applies its waste reduction concepts to each activity - from Customers to the Board of Directors to Support Staff to Production Plants to Suppliers.
TPS: Toyota Production System
Elimination of Waste
Complexity
Labor
Overproduction
Space
Energy
Defects
Muda
Materials Inventory Time Transportation
Acronym – CLOSED MITT
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1. 5S
2. Group technology
3. Quality at the source
4. JIT production
5. Kanban production control system
6. Minimized setup times
7. Uniform plant loading
8. Focused factory networks
Elimination of Waste
Minimizing Waste – 5S“Good factories develop beginning with the 5S’s. Bad factories fall apart beginning with the 5 S’s.”
- Hirouki Hirano
Japanese Translation English
Seiri Proper arrangement Sort
Seiton Orderliness Simplify
Seiso Cleanliness Sweep
Seiketsu Cleanup Standardize
Shitsuke Discipline Sustain
Minimizing Waste – 5S
A place for everything and everything in its place Not just a housekeeping issue Critical foundation for
Setup reduction Pull systems Maintenance Inventory management
Using Departmental Specialization (Job Shop) for plant layout can cause a lot of unnecessary material movement
Using Departmental Specialization (Job Shop) for plant layout can cause a lot of unnecessary material movement
Saw Saw
Lathe PressPress
Grinder
LatheLathe
Saw
Press
Heat Treat
Grinder
Note how the flow lines are going back and forthNote how the flow lines are going back and forth
Minimizing Waste: Group Technology
Press
Lathe
Grinder
Grinder
A
2
BSaw
Heat Treat
LatheSaw Lathe
PressLathe
1
Revising by using Group Technology Cells can reduce movement and improve product flow
Revising by using Group Technology Cells can reduce movement and improve product flow
Minimizing Waste: Group Technology
Minimizing Waste: JIT Only produce what’s needed The opposite of “Just In Case” philosophy Ideal lot size is one Minimize transit time Frequent small deliveries
Pro’s
•Minimal inventory
•Less space
•More visual
•Easier to spot quality issues
Con’s
•Requires discipline
•Requires good problem solving
•Suppliers or warehouses must be close
•Requires high quality
???
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Inventory Hides Problems
Work inprocess queues(banks)
Changeorders
Engineering designredundancies
Vendordelinquencies
Scrap
Designbacklogs
Machine downtime
Decisionbacklogs
Inspectionbacklogs
Paperworkbacklog
Minimizing Waste: JIT
Minimizing Waste – Quality at the Source “Do it right the first time” Call for help Immediately stop the process and correct it vs.
passing it on to inspection or repair
Andon
Jidoka
Minimizing Waste – Kanban
Signaling device to control flow of material
•Cards
•Empty containers
•Lights
•Colored golf balls
•Etc
Minimizing Waste – Setup Times
Long setup times drive: Long production runs Large lots Long lead times
JIT requires small lots and minimum kanbans Setup reduction
Focused efforts Problem solving Flexible equipment
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Not uniform Jan. Units Feb. Units Mar. Units Total
1,200 3,500 4,300 9,000
Uniform Jan. Units Feb. Units Mar. Units Total
3,000 3,000 3,000 9,000
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.
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.
How does the uniform loading help save labor costs?How does the uniform loading help save labor costs?
or
Minimizing Waste – Plant LoadingHeijunka
CoordinationSystem Integration
These are small specialized plants that limit the range of products produced (sometimes only one type of product for an entire facility)
These are small specialized plants that limit the range of products produced (sometimes only one type of product for an entire facility)
Minimizing Waste – Focused Factory Networks
Level payrolls
Cooperative employee unions
Subcontractor networks
Bottom-up management style
Quality circles (Small Group Problem Solving)
TPS – Respect for People
Keiretsu
1. All work shall be highly specified as to content, sequence, timing, and outcome
2. Every customer-supplier connection must be direct, and there must be an unambiguous yes-or-no way to send requests and receive responses
3. The pathway for every product and service must be simple and direct
4. 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
TPS – 4 Rules
Lean Implementation
Empowered WorkforceProblem Solving
Performance Measurement
Total QualityManagement
FlowProcess
StableSchedule
KanbanPull
InvolvedSuppliers
Continual InventoryReduction
ProductDesign
Summary and Conclusions… Lean Production is the set of activities that achieves
quality production at minimum cost and inventory The flow of material is pulled through the process by
downstream operations Lean originated with the Toyota Production System
and its two philosophies – elimination of waste, and respect for people
CLOSED MITT forms of waste