Just in Time

1
Just in Time

• Chapter 9
• Vollmann, Berry, Whybark, Jacobs

2
JIT in MPC

• Major elements of JIT
• JIT impact on MPC
• The Hidden Factory
• JIT Building Blocks in MPC

3
Major Elements of JIT Definition

• Minimize waste in manufacturing
• Time, energy, material, and errors
• The pursuit of
• Zero inventories
• Zero transactions
• Zero disturbances (routine execution of
  schedules).

4
JIT Examples

• Elimination of discrete manufacturing batches in
  favor of production rate goals,
• Reduction of WIP inventories,
• Production schedules that level capacity loads
  and keep them level,

5
JIT Examples (Cont.)

• Mixed MPS where all products are made more or
  less all the time.
• Visual control systems where the workers build
  the products and execute the schedule without a
  lot of paperwork.
• Direct ties to vendors who deliver quality
  products frequently(?).

6
Physical System Changes

• Set-up time reduction and drive towards
  constantly smaller lot sizes (EOQ).
• Improved quality through process improvement to
  avoid work stoppages of the flow line (no defects
  goal kaizen).
• Total Preventative Maintenance
• Poka-yoke (fool proofing)

7
Physical System Changes

• Group the equipment for cellular manufacturing
  (this minimizes travel distances and inventories
  between machines). U shaped layout.
• Cells increase worker interaction (involvement)
  and reduce material handling. Increased cross
  training makes capacity more flexible.

8
JIT Benefits

• Mfg. throughput time reductions.
• Less distance traveled.
• Reduced transactions
• Simplified MPC systems
• Reduce changeover times.
• Greater responsiveness to market demand.

9
JIT Benefits

• Inventory reductions
• Labor cost reductions
• More satisfied/cohesive workers.
• Better team working.
• Space reduction (only if).
• Quality cost reductions.
• Quality improvements

10
JIT Impact on MPC

• JIT reduces the number of parts planned and the
  number of levels in the BOM.
• JIT makes MPC work at the level of assemblies
  rather than at detailed planning.
• MPS will use relatively level capacity loading
  (rate based so many units per hour (or day)).

11
JIT Impact on MPC

• Lead times are reduced so that inventories that
  used to be used to provide inventories in
  anticipation of customer orders (made-to-stock)
  are now doing MTO or ATO better able to respond
  to customer orders.
• This in turn can affect Demand Management.

12
JIT Impact on MPC

• In JIT orders move through the plant so quickly
  that there is no need to have a complex
  production activity control.
• In JIT the vendor is paid depending on the number
  of products that are completed each time period.
• The intent is to design manufacturing cells so
  the goods follow through routinely. Simple
  systems are employed by shop people.

13
The Hidden Factory (one makes things and the
other paper transactions).

• Logistical transactions
• Balancing transactions
• Quality transactions
• Change transactions

14
Logistical transactions

• Includes ordering, execution, and confirmation of
  materials moving from one location to another.
• It includes the costs of personnel, in receiving,
  shipping, expediting, data processing,
  accounting, error follow up.
• Under JIT the goal is to eliminate as much of
  this as possible. If flow is simplified, fast,
  and guaranteed there is no need for paperwork.

15
Balancing Transactions

• Includes transactions needed for production
  control, purchasing, master scheduling,
  forecasting, and customer order processing.
• They are about 10-20 of the total manufacturing
  overhead costs.
• JIT offers the opportunity to reduce these costs.

16
Quality Transactions

• Includes identification and communication of
  specifications, certification that other
  transactions have taken place, and recording of
  backup data.
• JIT with closer coupling of production and
  consumption has faster quality monitoring and
  response capability.

17
Change Transactions

• Including engineering changes and all those that
  update MPC systems such as routings, bill of
  materials and specifications.

18
Attacks on transactions

• Find ways to reduce the number of transactions.
• Stability will help and JIT is based on
  stabilized operations.
• Automate the transactions (bar coding, RFID).
• Role of ERP?

19
JIT OBJECTIVES

• Zero inventories
• Zero Lead Time
• Zero Failures
• Flow Process
• Flexible Manufacture
• Eliminate Waste
• Fig. 9.4

20
Impact of Product Design

• If the handle base is redesigned the handle base
  becomes a common part and the ring placement is
  common between the two handle models. Fig9.13
• The only difference would be the choice of handle
  parts.
• BOM is simplified Fig 9.15

21
Process Design

• It may now be possible to use the same equipment
  to attach both kinds of plastic handles to the
  handle base.
• Perhaps a cell may be formed Fig 9.14
• Observe that inventory is smaller (containers).
  Fig 9.14
• There seems to be slack capacity. Fig 9.14

22
BOM Implications

• Number of parts has gone down.
• Product structure tree now looks slimmer
• Handle assemblies have ceased to exist as part of
  the structure.
• Handle assembly (Part 137) can exist as a phantom
  assembly.