???(just in time,JIT)??

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???(just in time,JIT)??

• ??????????,????(Taiichi Ohno)?
• ??
• ?????????????????????????????
• ??
• ????
• ??????
• ?????????
• ?????
• ????

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JIT??????????
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???????1

• ????(overproduction)
• ????(waiting time)
• ??????(unnecessary transporting)
• ??(inventory)
• ????(processing waste)
• ????????
• ?????

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???????2

• ???????(inefficient work method)
• ????????????,???????
• ????
• ????
• ????????????

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Waste in Operations
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Waste in Operations
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Waste in Operations
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?????????1

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• ???????????,??????????????
• ?????????
• ?????????????????,?????????????
• ???????????????

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?????????2

• ????????????????????,????????????
• ??????????
• ???????
• ??????????????????????
• ?????????????

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Basic Elements of JIT1

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• ???????(??/?????)
• ????,???????(??/?????)
• ????(??/?????)
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• ???????(??/?????)

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Basic Elements of JIT2

• Cellular layouts (????
• Pull production system(???????)
• Flexible resources (????)
• Kanban production control(???????)
• Small-lot production(????)

• Quick setups (????)
• Uniform production levels (???????)
• Quality at the source(????)
• Total productive maintenance (???????)
• Supplier networks(???????)

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Flexible Resources

• Multifunctional workers (???)
• Perform more than one job
• General purpose machines (????)
• Perform several basic functions
• Study operators improve operations

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Cellular Layouts

• Group dissimilar machines in manufacturing cell
  to produce family of parts
• Work flows in one direction through cell
• Cycle time adjusted by changing worker paths

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Manufacturing Cell with Worker Routes
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Worker Routes Lengthened as Volume Decreases
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???????

• ????(push system)(??,MPR)
• ???????????,??????????
• ????(pull system)(??,JIT)
• ????????????????????????????

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Kanban Production Control System(????????)

• Kanban card indicates standard quantity of
  production
• Derived from two-bin inventory system(???)
• Kanban maintains discipline of pull production
• Production kanban(????) authorizes production
• Withdrawal kanban(????) authorizes movement of
  goods

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A Sample of Kanban
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The Origin of Kanban
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Single-Card Kanban System
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Single-Card Kanban System
Receiving post
Storage area
Kanban card for product 1
Kanban card for product 2
Empty containers
Full containers
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Single-Card Kanban System
Receiving post
Storage area
Kanban card for product 1
Kanban card for product 2
Empty containers
Full containers
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Single-Card Kanban System
Receiving post
Storage area
Kanban card for product 1
Kanban card for product 2
Empty containers
Full containers
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Single-Card Kanban System
Receiving post
Storage area
Kanban card for product 1
Kanban card for product 2
Empty containers
Full containers
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Single-Card Kanban System
Receiving post
Storage area
Kanban card for product 1
Kanban card for product 2
Empty containers
Full containers
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Single-Card Kanban System
Receiving post
Storage area
Kanban card for product 1
Kanban card for product 2
Empty containers
O2
Fabrication cell
O3
O1
Full containers
O2
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???? single kanban
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Types of Kanbans Dual kanbans
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Dual kanban vs. single kanban

• Dual kanban
• Is used when material is not necessarily moving
  between two consecutive processes, or when there
  is more than one input to a process and the
  inputs are dispersed throughout the facility.
• Single kanban
• Is used when the processes are tightly linked.

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Types of Kanbans

• Kanban Square
• Marked area designed to hold items
• Signal Kanban
• Triangular kanban used to signal production at
  the previous workstation
• Material Kanban
• Used to order material in advance of a process
• Supplier Kanbans
• Rotate between the factory and suppliers

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Types of Kanbans kanban square and kanban racks
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Types of Kanbans signal kanbans
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?????????

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• ???????????,??????????
• ????????????

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Single-Card Kanban System

• Each container must have a card
• Assembly always withdraws from fabrication (pull
  system)
• Containers cannot be moved without a kanban
• Containers should contain the same number of
  parts
• Only good parts are passed along
• Production should not exceed authorization

Part Number 1234567Z Location Aisle 5 Bin
47 Lot Quantity 6 Supplier WS
83 Customer WS 116
KANBAN
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??(??)?????1

• K?????
• d??????????(??????) ?
• p??????????????
• W?????????????,????????????
• C??????????
• X??????????????(10??)

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??(??)?????2
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??(??)?????3
where N number of kanbans or containers d
average demand over some time period L
lead time to replenish an order S safety
stock C container size
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????????

• ?????????4????????????????????????1???????????0.02
  ?????0.08????????????????????2000?????????????????
  ?????,????????????10?
• ??????22???,?????????????

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??? (Small-lot production) ???

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Inventory Hides Problems
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Lower Levels of Inventory Expose Problems
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Components of Lead Time(???????)

• Processing time
• Reduce number of items or improve efficiency
• Move time
• Reduce distances, simplify movements, standardize
  routings
• Waiting time
• Better scheduling, sufficient capacity
• Setup time
• Generally the biggest bottleneck

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???? (Quick setups)

• Single-digit setup
• The goal of having a setup time of less than 10
  minutes.
• ???????????? (single-minute exchange of dies,
  SMED)

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?????????

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• 2. ????????????????????
• 3. ??????????????
• 4. ???????????
• 5. ???????
• 6. ???????????
• 7. ????????????

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???????????

• ??????????(??,???????????)
• ???????????

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Common Techniques for Reducing Setup Time1
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Common Techniques for Reducing Setup Time2
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Common Techniques for Reducing Setup Time3
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????? (Uniform Production)

• Results from smoothing production requirements
• Kanban systems can handle /- 10 demand changes
• The way to reduce variability in production
• Smooths demand across planning horizon
• Mixed-model assembly steadies component production

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?????1

• The APP of TOYOTA 4500 vehicles per week.
• Two full shifts, five days per week ? 450
  vehicles per shift (480 minutes)
• Three models are produced Camry (C), Avalon (A),
  and Sienna (S).
• 200 Camry, 150 Avalons, and 100 Siennas per shift
• Cycle time 480/4501.067 (min)

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?????2

• First
• 200 Cs ? 150 As ? 100Ss
• High average cycle inventory level
• Lumpy requirements
• Second
• 4 Cs ? 3 As ? 2Ss
• The cycle 9(1.067)9.60 (50 times per shift)

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?????3

• Third
• C ? S ? C ? A ? C ? A ? C ? S ? A
• The setup times must be very short.
• Component requirements is steady
• Capacity requirements are smoothed

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Quality at the Source1

• Jidoka (???)
• ????????????
• Andon (??)
• ????????????,???????????
• Undercapacity scheduling allows for planning ,
  problem solving maintenance

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Quality at the Source2

• ?????????POKAYOKE ,?????,??,???????????(??)?????,?
  ????????????????,???????????????,?????????
• ?????? (visual control) ?????????????????????????
  ??????????????,????????????????

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Visual Control
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Visual Control
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Visual Control
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Kaizen (??)

• Continuous improvement
• Requires total employment involvement
• Essence of JIT is willingness of workers to
• Spot quality problems
• Halt production when necessary
• Generate ideas for improvement
• Analyze problems
• Perform different functions

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Total Productive Maintenance (TPM)

• Breakdown maintenance
• Repairs to make failed machine operational
• Preventive maintenance
• System of periodic inspection maintenance to
  keep machines operating
• TPM combines preventive maintenance total
  quality concepts

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TPM Requires Management to

• Design products that can be easily produced on
  existing machines
• Design machines for easier operation, changeover,
  maintenance
• Train retrain workers to operate machines
• Purchase machines that maximize productive
  potential
• Design preventive maintenance plan spanning life
  of machine

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??JIT???5S??
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Supplier Policies1

• Locate near to the customer
• Use small, side loaded trucks and ship mixed
  loads
• Consider establishing small warehouses near to
  the customer or consolidating warehouses with
  other suppliers

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Supplier Policies2

• Use standardized containers and make deliveries
  according to a precise delivery schedule
• Become a certified supplier and accept payment at
  regular intervals rather than upon delivery

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??????? (JIT II)

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??JIT???1

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??JIT???2

• ?????????? JIT,????????
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??JIT???3

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??JIT???

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• ??????????????,???????? JIT?
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• ???? JIT ?????,???????????

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JIT?????1

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JIT?????2

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?????????JIT

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JIT?????1

• ????
• JIT???????
• Problem-solving
• Lost some autonomy (little or no safety stocks)
• ?????
• Scheduling,expediting and improving productivity
  ? lower-level personnel
• ?????????
• JIT vs. Production volume
• Managements flexibility vs. Union

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?????2

• ????
• Cellular design ? costly
• ?????
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• Small lot sizes vs. large number of setups
• ?????
• Small shipments of purchased items vs. geographic
  dispersion of suppliers