LEAN system

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LEAN system
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Supporting goals

• A balanced system, smooth, rapid flow of
  materials and/or work
• Supporting goals
• Eliminate disruption
• Make the system flexible
• eliminate waste, especially exess inventory

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Value

• That customer is willing to pay
• That changes products color, function, shape,
  other attributes so that the product is getting
  closer to the customers requirements
• That we do right at first time

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Wastes

• Those processes which directly do not create
  value for customers (muda, mura, muri)
• that are not necessary, and must be eliminated
• That are necessary, because these are supporting
  value-add processes, cannot be eliminated (like
  transporting)
• Muda 7 wastes of lean
• Mura not leveled workflow
• Muri overloading of workers and assets

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There are 7 wastes in LEAN (TIMWOOD)

• Inventory
• Overproduction
• Waiting
• Unnecessary transportation
• Processing waste
• Inefficient work methods
• Defects

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Lean thinking
Operation
Traditional improvement
Lean improvement
Non value-add process
Value-add process
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JIT Building Blocks

• Process design
• Product design
• Personnel/organizationalelements
• Manufacturing planning and control

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Process Design

• Small lot sizes
• Setup time reduction
• Manufacturing cells
• Limited work in process
• Quality improvement
• Production flexibility
• Little inventory storage

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Benefits of Small Lot Sizes
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Setup time

• reducing changeover time ( because small lots
  require frequent setups)
• SMED (single minute exchange of die)
• External
• Internal activities.

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Manufacturing cells

• In Functional Manufacturing similar machines are
  placed close together (e.g. lathes, millers,
  drills etc)
• In Cellular Manufacturing systems machines are
  grouped together according to the families of
  parts produced.
• The major advantage is that material flow is
  significantly improved, which reduces the
  distance travelled by materials, inventory and
  cumulative lead times.

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Quality improvement

• Kaizen continuous improvement of the system
• Jidoka (Autonomation) automatic detection of
  defects during production. It consist two
  activities
• One for detecting defects when they occur
• Another for stopping production to correct the
  cause of defects.
• Poka Yoke safeguards built into the process to
  reduce the possibility of errors.

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Work flexibility

• Overall goal of lean is to achieve the ability to
  process mix of products in a smooth flow.
• One potential obstacle is bottlenecks, which
  occur when portions of the system become
  overloaded. Because of
• The absence of workers ? cross trained workers
• Not leveled workflow ? use takt time
• Example
• Total time per shift is 480 minutes per day
• There are two shifts per day
• There are two 20-minutes break and a 30 minutes
  lunch break per shift.
• Daily demand is 80 pieces
• Net time available per day 2(480-202-30)820min
  utes
• Takt time820minutes/80 pieces10,25 minutes
• If the actual cycle time is higher, our customers
  wont get their needs, if the actual cycle time
  is lower, there will be overproduction, and we
  have to inventory surplus products.

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Inventory storage

• Inventory storage is a waste,
• a buffer which can cover up problems, partly
  because inventory makes them seem less serious.

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Product Design

• Standard parts fewer parts to deal with ?lower
  training costs
• Modular design easy to satisfy different needs
• Highly capable production systems quality is
  designed into the product and the production
  process
• Concurrentengineering

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Personnel/Organizational Elements

• Workers as assets
• Cross-trained workers
• Continuous improvement
• Cost accounting
• Leadership/project management

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Manufacturing Planning and Control

• Level loading
• Pull systems
• Visual systems
• Close vendor relationships
• Reduced transaction processing
• Preventive maintenance

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Mixed model sequencing

• the sequence (on the base of setup time and setup
  cost let it be now A,C,B)
• how many times the sequence should be repeated
  (determine the smallest integer)
• how many units to produce

Model Daily quantity Units per cycle
A 10 10/52
B 15 15/53
C 5 5/51
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Pull/Push Systems

• Pull system System for moving work where a
  workstation pulls output from the preceding
  station as needed. (e.g. Kanban)
• Push system System for moving work where output
  is pushed to the next station as it is completed

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Visual system

• Kanban- a manual system responds to signals of
  the need for delivery of parts and materials
  (both to the factory and between the workstation)
• Production kanban
• Conveyance kanban

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Traditional Supplier Network
Figure 12.4a
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Tiered Supplier Network
Figure 12.4b
First Tier Supplier
Second Tier Supplier
Third Tier Supplier
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Comparison of JIT and Traditional
Table 12.3
Factor Traditional JIT
Inventory Much to offset forecast errors, late deliveries Minimal necessary to operate
Deliveries Few, large Many, small
Lot sizes Large Small
Setup runs Few, long runs Many, short runs
Vendors Long-term relationships are unusual Partners
Workers Necessary to do the work Assets
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Preventive maintenance

• Total Productive Maintenance operators
  responsible for the equipments they use
• Housekeeping 5S
• Sort
• Straighten
• Sweep
• Standardize
• Self-discipline

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Thank you for your attention!