1

Just-in-Time/Lean Production

A repetitive production system

in which the processing and movement of materials and goods occur

just as they are needed!

2

Pre-JIT: Traditional Mass Production

Big lot sizesLots of inventory”PUSH” material to nextstage

Lowerper unit

cost

Big purchase shipments

Big “pushes” of finished goodsto warehouses or customers

???

3

Post-JIT: “Lean Production”

Tighter coordination along the supply chainGoods are pulled along

— only make and ship what is neededSmaller lotsFaster setupsLess inventory, storage space”PULL” material to next stage

Minimalor no

inventoryholding

cost

Smaller shipments

Goods are pulled out ofplant by customer demand

4

JIT Goals(throughout the supply chain)

• Eliminate disruptions

• Make the system flexible

• Reduce setup times and lead times

• Minimize inventory

• Eliminate waste

5

WasteDefinition:

Waste is ‘anything other than the minimum amount of equipment, materials, parts, space, and worker’s time, which are absolutely essential to add value to the product.’

— Shoichiro Toyoda President, Toyota

6

Forms of Waste:

• Overproduction

• Waiting time

• Transportation

• Processing

• Inventory

• Motion

• Product Defects

7

Inventory as a Waste

• Requires more storage space

• Requires tracking and counting

• Increases movement activity

• Hides yield, scrap, and rework problems

• Increases risk of loss from theft, damage, obsolescence

8

Building Blocks of JIT

• Product designStandard partsModular designQuality

• Process design• Personnel and organizational elements• Manufacturing planning and control

MPC

Staff ORG

Process Design

Product Design

9

Process Design

• “Focused Factories”

• Group Technology

• Simplified layouts with little storage space

• Minimum setups

10

Personnel and Organizational Elements

• Workers as assets

• Cross-trained workers

• Greater responsibility at lower levels

• Leaders as facilitators, not order givers

11

Planning and Control Systems

• “Small” JIT

• Stable and level schedules

– Mixed Model Scheduling

• “Push” versus “Pull”

– Kanban Systems

12

Kanban

Uses simple visual signals to control production

• Examples:

empty slot in hamburger chute

empty space on floor

kanban card

13

Kanban Example

Workcenter B uses parts produced by Workcenter A

How can we control the flow of materials so that B alwayshas parts and A doesn’t overproduce?

Workcenter A Workcenter B

14

When a container is opened by Workcenter B, its kanban card is removed and sent back to Workcenter A.This is a signal to Workcenter A to produce another box of parts.

Kanban card: Signal to produceWorkcenter A Workcenter B

Kanban Card

15

Empty Box: Signal to pull

Empty box sent back. Signal to pull another full box intoWorkcenter B.

Workcenter A Workcenter B