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					          LEARNING OBJECTIVES
•Understand the ultimate goals of a lean processes
•Lean to use value-stream mapping to model processes
•Understand the key design principles of a lean value stream
•Lean to develop a future state
•Understand the key challenges of implementing lean value
streams
               LEAN THINKING
Waste
Use of resources beyond what customer needs.
 There exist seven types of waste
  1. Over-production
  2. Inventory
  3. Motion
  4. Waiting
  5. Transportation
  6. Over-processing
  7. Rework
             THE VALUE STREAM

• A value stream is all the actions (both value added and
  non-value added) currently employed to bring a
  product to completion. The focus is on the production
  flow from raw material into the hands of the
  customers.
• Source:Rother and Shook (2003), Learning to See –
  Value-stream Mapping to Create Value and Eliminate
  Muda
Main Focus
• Big picture (door-to-door), not individual processes
• Improving the entire conversion process, not just parts
• Door-to-door perspective
           The Value Stream


               Our Focus
                                   Customers

                    Value Stream
Supplier
                   Our Plant
A Sample VSM
    CHARACTERISTICS OF VALUE-STREAM MAPPING
•   Helps visualizing entire operations
•   Provides a common language when talking about the process
•   Makes decisions about flow apparent
•   Used to implement various lean principles
•   Forms basis for implementation plan by serving as blueprint
•   Shows linkage between information and material flow

    Material flow: Flow of raw materials, parts, components, and products.
    Ultimate goal is single piece continuous flow

  Information flow: Flow of orders, inventory level information, etc.
  Ultimate goal is achieving an information flow such that one process
  produces only what the next process needs and when it needs it
• Extended value stream mapping includes suppliers and customers

See “Seeing the Whole” by Jones and Womack
    SELECTING A PRODUCT FAMILY

                   Manufacturing Steps & Equipment
Product     1        2         3         4         5        6         7            8
   A        X        X         X
   B        X        X         X
   C        X        X         X
   D                                     x         x        x         x            x
   E                                     X                  x         x            x
   F                                     X         x        x         x
   G                                     X                  x         x            x

• Drawing entire VSM for all products becomes confusing
•Focus on door-to-door activities of one product or one product family
Product family: Group of products that pass through similar processing steps and
over common equipment
         VALUE STREAM MAPPING

  Product Family A     Current-state map
                       • Is drawn by gathering information on shop floor
Product Family B       • Helps identifying improvement opportunities
                       • Provides information for future-state design
   Current State Map
                       Future-state map
                       • Idea come to mind during current-state mapping
   Future State map
                        8 key questions are answered
                       • First draft should not take more than a few days
   Implementation      • Can be fine-tuned during implementation
                       • During continuous improvement, there must
                        always a future map
                 MAPPING TIPS

• Collect current-state information while walking along
  the actual pathways yourself
• Begin with quick walk along entire door-to-door
  stream
• Begin with the shipping end of the value stream
• Bring stop watch and to not rely on standard times
• Map entire value stream yourself
• Always draw by hand in pencil
VSM Symbols
                Explanations
                      Represents Movement of production
                      material by push

                      Movement of finished goods
                      To the customer

                      Supermarket


                      Withdrawal

                      Transfer of controlled
                      quantities of material
Max 20 pieces         between processes in a
  FIFO                „First-In-First-Out“ sequence
             Explanations
                   Manual Information flow: For example,
                   production schedule or shipping schedule

                   Electronic Information Flow: For example via
                   electronic data interchange

Weekly Schedule    Information: Describes an information flow

                   Production Kanban: The „One-per-container“
        20         kanban. (dotted line indicates
                   Kanban paths) Card or device that tells a
                   process how many of what can be produced
                   and gives permission to
                   do so.

                   Withdrawal Kanban: Card or device that
                   instructs the material handler to get and
                   transfer parts (i.e. from a supermarket to the
                   consuming process).
Explanations
  Signal Kanban: The „one-per-batch“ kanban. Signals
  when a recorder point is reached and another batch
  needs to be produced. Used where supplying process
  must produce in batches because changeovers are
  required.

  Sequenced-Pull Ball: Gives instruction to immediately
  produce a predetermined type and quantity, typically
  one
  unit. A pull system for subassembly processes without
  using a supermarket.

  Kanban Post: Place where kanban are collected and
  held for conveyance.


  Kanban Arriving in Batches
         Explanations
               Load Leveling: Tool to intercept batches
OXOXOX         of kanban and level the volume and mix
               of them over a period of time.

               „Go See“ Production Scheduling:
               Adjusting schedules based on checking
               inventory levels.
       KEY PROCESS MEASURES
• Cycle time (C/T): The time between two
  successive completions of a part or product

• Value creating time (VCT): The time spent on
  activities that transform the product in a way that
  the customer is willing to pay for

• Lead time (L/T): The time it takes one piece to
  move all the way through the process, from start
  to finish
         KEY PROCESS MEASURES
• Available working time: Time per shift that the process is available
• C/O Changeover time: is the time it takes to switch from
  producing one time of product to another
• Uptime: Percentage of working time an process is on average
  available for production (incl. changeover time)
• Number of operators: Number of people it takes to operate the
  process
• EPEx : Every part every x seconds/days/weeks.
• Pack size : Number of units per pack
• Scrap rate: Percentage of units produced that are scrap
• Inventory: Number of units or number of days of supply of
  inventory. For instance, if 1000 units are on hand and 500 units per
  day are used than the inventory can be expressed as 1000 units or 2
  day.
AN EXAMPLE
ACME PLANT LAYOUT
                                         ACME STAMPING DATA SET

Acme Stamping Company produces several components for vehicle
      assembly plants. This case concerns one product family, a         Work Time
      steel instrument-panel bracket subassembly in two types: one       20 days in a month
      each for left-hand and right-hand drive versions of the same
      automobile model. These components are sent to the                 Two shift operation in all production departments
State Street Vehicle Assembly Plant (the customer)                       Eight (8) hours every shift, with overtime if
Production Processes                                                        necessary
     Acme´s processes for this product family involve stamping a        Two 10-minute breaks during each shift. Manual
      metal part followed by welding and subsequent assembly.               processes stop during breaks. Unpaid lunch
      The components are then staged & shipped to the vehicle
      assembly plant on a daily basis                                   Acme Production Control Department
     Switching between Type „LH“ (left-hand-drive) brackets             Receives State Street´s 90/60/30-day forecasts and
      requires a 1 hour changeover in stamping and a 10-minute              enters them to MRP
      fixture change in the welding processes
                                                                         Issues Acme 6-week forecast to Michigan Steel Co.
     Steel coils are supplied by Michigan Steel Co. Steel deliveries       via MRP
      to Acme arrive on Tuesdays and Thursdays
Customer Requirements                                                    Secures coil steel by weekly FAXed order release to
     18,400 pieces per month                                               Michigan Steel Co.
                 - 12,000 per month of Type „LH“                         Receives daily firm order from State Street
                 - 6,400 per month of Type „RH“                          Generates MRP-based weekly departmental
     Customer plant operates on two shifts                                 requirements based upon customer order, WIP
     Palletized returnable tray packaging with 20 brackets in a tray       inventory levels, F/G inventory levels, and
      and up to 10 trays on a pallet. The customer orders in                anticipated scrap and downtime
      multiples of trays
     One daily shipment to the assembly plant by a truck
                                                                         Issues weekly build schedules to Stamping,
                                                                            Welding, and Assembly processes
                                                                         Issues daily shipping schedule to shipping
                                                                            Department
                               ACME STAMPING DATA SET
ACME STAMPING DATA SET – CONTINUED                                  4. Assembly Workstation I (dedicated to this product
1. Stamping (The press makes parts for many Acme                    family)
products)
                                                                     Manual process with one operator
     Automated 200 Ton press with coil (automatic) material feed
     Cycle Time: 1 second (60 pieces per minute)                    Cycle time: 62 seconds
     Changeover time: 1 hour (good piece to good piece)             Changeover time: none
     Machine reliability: 85%                                       Reliability: 100%
     Observed Inventory:                                            Observed Inventory:
       - 5 days of coils before stamping                                  - 1,200 pieces of Type „LH“
       - 4,600 pieces of Type „LH“ finished stampings
                                                                          - 640 pieces of Type „RH“
       - 2,400 pieces of Type „RH“ finished stampings
2. Spot Weld Workstation I (dedicated to this product family)       5. Assembly Workstation II (dedicated to this product
     Manual process with one operator                              family)
     Cycle time: 39 seconds                                         Manual process with one operator
     Changeover time: 10 minutes (fixture change)                   Cycle Time: 40 seconds
     Reliability: 100%                                              Changeover time: none
     Observed Inventory:
      - 1,100 pieces of Type „LH“ / 600 pieces of Type „RH“
                                                                     Reliability: 100%
3. Spot Weld Workstation II (dedicated to this product family)       Observed Finished-Goods Inventory in Warehouse:
     Manual process with one operator                                    - 2,700 pieces of Type „LH“
     Cycle time: 46 seconds                                              - 1,440 pieces of Type „RH“
     Changeover time: 10 minutes (fixture change)                  6. Shipping Department
     Reliability: 80%                                               Removes parts from finished goods warehouse and
     Observed Inventory:                                           stages them for truck shipment to customer.
      - 1,600 pieces of Type „LH“ / 850 pieces of Type “RH”
References

				
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