1. Pull Production/ Just In Time
Compiled by:
Alex J. Ruiz-Torres, Ph.D.
From information developed by many.

2. Outline Pull Production Definitions Goals and benefits Main components
JIT and suppliers

3. Pull Production / Just in Time
Definitions
Scheduling system that tells you what to produce, when to produce it, and how much to produce.
A process that aims to arrange an organization so that customer preference or orders are what cause materials to be "pulled" through a system.
The idea is that the manufacturer only produces what the consumer wants when the consumer wants them. In other words, a product need only be produced at the same rate that they are being sold.

4. Pull Production / Just in Time
Benefits
Inventory is reduced at all points (RM, WIP, FG), matching demand.
Improvement in quality given its easier to find and address quality issues.
Makes operational problems visible (eg. supplier unreliability or poor yields, long setup times, …)

5. Pull/JIT Components Production control system based on Kanbans
Standardized containers
Supermarkets (name used for inventory points/ stocks/ warehouses)
Build to consumption (pull!)

6. Pull/JIT Components
We first need to understand traditional “push” systems
Scheduling based on the Master Production Schedule, which is based on a combination of forecasts and sales
Scheduling/production of batches based on the MPS. Production of large quantities given long setups (maximize local productivity)
Result is “large” inventories and production that “sits” around
This could mean using raw materials that are later need for a needed product
This could result in a large batch that is later found defective

7. Pull/JIT Components Kanban Production is controlled by signals
Cards or other visual “information” holding device
It includes information on
Part name and number
Quantity
Origin
Destination
E-Kanbans are widely used

8. Pull/JIT Components

9. Pull/JIT Components Kanban Rules Only conforming product flows
Product always flows with a kanban
No kanban card, no production
Standardized containers
How many cards?
numK =Number of kanban cards (also containers)
D = Demand per unit of time
ss = Safety Stock
L = Lead time
a = Container capacity (also the minimum amount to be produced)
numK = DL (1 + ss)/a

10. Pull/JIT Components

11. How Pull Works Supplier Production CK Supermarket DC 1 PK
Supermarket PC PK
Production
Supermarket DC 1 CK SK

12. Supplier Production CK CK Supermarket DC 1 Supermarket PC PK CK CKSK

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14. Supplier Production CK CK Supermarket DC 1 Supermarket PC PK CK CKSK

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16. Supplier Production CK PK Supermarket DC 1 PK PK CK Supermarket PC CKSK

17. Supplier Production CK CK Supermarket DC 1 PK Supermarket PC PK PK CKSK

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20. Supplier Production CK CK Supermarket DC 1 PK PK Supermarket PC PK CKSK

21. Supplier Production CK CK Supermarket DC 1 SK PK PK PK Supermarket PC

22. Supplier Production SK CK CK Supermarket DC 1 PK PK PK Supermarket PC

23. Supplier Production CK CK Supermarket DC 1 PK PK PK SK Supermarket PC

24. Supplier Production CK CK Supermarket DC 1 PK PK PK Supermarket PC CKSK

25. Pull/JIT Components Additional comments
Kanbans control the maximum inventory
The maximum inv = # cards x Qty per card
The minimum is 0 if all containers have been used and production/suppliers have yet to replace
E-Kanbans
Replaces the cards for “long distance” information flows
Information from factory facility to supplier
Between distant work-centers
Kanbans must include date information as to maintain a constant number of cards
Requires level production and stable demand (Heijunka)

26. Pull/JIT Components Suppliers and global sourcing
JIT sourcing requires willing suppliers that
can deliver reliably and frequently while selling at a “fair price”,
have a well designed transportation system/ strategy,
possibly have production or warehousing facilities close by,
are willing to collaborate in design of new products and share information about production plans.