lean systems. characteristics of lean systems: just-in-time pull method of materials flow pull...

Lean Lean SystemsSystems

Characteristics of Lean Systems: Characteristics of Lean Systems: Just-in-TimeJust-in-Time Pull method of materials flowPull method of materials flow Consistently high qualityConsistently high quality Small lot sizesSmall lot sizes Uniform workstation loadsUniform workstation loads Standardized components and work methodsStandardized components and work methods Close supplier tiesClose supplier ties Flexible workforceFlexible workforce Line flowsLine flows Automated productionAutomated production Preventive maintenancePreventive maintenance

Lot Size and Cycle InventoryLot Size and Cycle Inventory

Lot Size and Cycle InventoryLot Size and Cycle Inventory

Lot size = 100

On

-han

d in

ven

tory

5 10 15 20 25 30

Time (hours)

100 –

75 –

50 –

25 –

0 –

Average cycle inventory

Figure 16.1

Lot Size and Cycle InventoryLot Size and Cycle Inventory

Average cycle inventory

Lot size = 100

On

-han

d in

ven

tory

5 10 15 20 25 30

Time (hours)

100 –

75 –

50 –

25 –

0 –

Figure 16.1

Lot Size and Cycle InventoryLot Size and Cycle Inventory

Average cycle inventory

Lot size = 100

Lot size = 50On

-han

d in

ven

tory

5 10 15 20 25 30

Time (hours)

100 –

75 –

50 –

25 –

0 –

Figure 16.1

Lot Size and Cycle InventoryLot Size and Cycle Inventory

Average cycle inventory

Lot size = 100

Lot size = 50On

-han

d in

ven

tory

5 10 15 20 25 30

Time (hours)

100 –

75 –

50 –

25 –

0 –

Figure 16.1

Lot Size and Cycle InventoryLot Size and Cycle Inventory

Average cycle inventory

Lot size = 100

Lot size = 50On

-han

d in

ven

tory

5 10 15 20 25 30

Time (hours)

100 –

75 –

50 –

25 –

0 –

Figure 16.1

Figure 16.2

Scrap Unreliable suppliers

Capacity imbalance

Continuous Improvement with Lean Systems

Continuous Improvement with Lean Systems

Single-Card Kanban SystemSingle-Card Kanban System

Storage area

Empty containers

Full containers

Single-Card Kanban SystemSingle-Card Kanban SystemReceiving post

Kanban card for product 1

Kanban card for product 2

Figure 16.3

Fabrication cell

O1

O2

O3

O2

Assembly line 1

Assembly line 2

Storage area

Empty containers

Full containers

Single-Card Kanban SystemSingle-Card Kanban SystemReceiving post

Kanban card for product 1

Kanban card for product 2

Figure 16.3

Fabrication cell

O1

O2

O3

O2

Assembly line 1

Assembly line 2

Storage area

Empty containers

Full containers

Single-Card Kanban SystemSingle-Card Kanban SystemReceiving post

Kanban card for product 1

Kanban card for product 2

Figure 16.3

Fabrication cell

O1

O2

O3

O2

Assembly line 1

Assembly line 2

Storage area

Empty containers

Full containers

Single-Card Kanban SystemSingle-Card Kanban SystemReceiving post

Kanban card for product 1

Kanban card for product 2

Figure 16.3

Fabrication cell

O1

O2

O3

O2

Assembly line 1

Assembly line 2

Storage area

Empty containers

Full containers

Single-Card Kanban SystemSingle-Card Kanban SystemReceiving post

Kanban card for product 1

Kanban card for product 2

Figure 16.3

Fabrication cell

O1

O2

O3

O2

Assembly line 1

Assembly line 2

Storage area

Empty containers

Full containers

Single-Card Kanban SystemSingle-Card Kanban SystemReceiving post

Kanban card for product 1

Kanban card for product 2

Figure 16.3

Fabrication cell

O1

O2

O3

O2

Assembly line 1

Assembly line 2

Storage area

Empty containers

Full containers

Single-Card Kanban SystemSingle-Card Kanban SystemReceiving post

Kanban card for product 1

Kanban card for product 2

Figure 16.3

Fabrication cell

O1

O2

O3

O2

Assembly line 1

Assembly line 2

Single-Card Kanban SystemSingle-Card Kanban SystemK

AN

BA

N

Part N

um

ber:

1234567Z

Lo

cation

:A

isle 5B

in 47

Lo

t Qu

antity:

6

Su

pp

lier:W

S 83

Cu

stom

er:W

S 116

Each container must have a cardEach container must have a card Assembly always withdraws from Assembly always withdraws from

fabrication (pull system)fabrication (pull system) Containers cannot be moved Containers cannot be moved

without a kanbanwithout a kanban Containers should contain the Containers should contain the

same number of partssame number of parts Only good parts are passed alongOnly good parts are passed along Production should not exceed Production should not exceed

authorizationauthorization

Number of ContainersNumber of Containers

Number of ContainersNumber of Containers

k = d( w + p )( 1 + )

c

d = 2000 units/day p = 0.02 day = 0.10w = 0.08 day c = 22 units

Westerville Auto Parts

Example 16.1

Number of ContainersNumber of Containers

k = 2000( 0.08 + 0.02 )( 1 + 0.10 )

22

d = 2000 units/day p = 0.02 day = 0.10w = 0.08 day c = 22 units

Westerville Auto Parts

Example 16.1

Number of ContainersNumber of Containers

k = 2000( 0.08 + 0.02 )( 1 + 0.10 )

22

d = 2000 units/day p = 0.02 day = 0.10w = 0.08 day c = 22 units

Westerville Auto Parts

Example 16.1

Number of ContainersNumber of Containers

k = 10 containers

d = 2000 units/day p = 0.02 day = 0.10w = 0.08 day c = 22 units

Westerville Auto Parts

Example 16.1

Number of ContainersNumber of Containers

d = 2000 units/day p = 0.02 day = 0.10w = 0.060.06 day c = 22 units

Westerville Auto Parts

k = d( w + p )( 1 + )

c

k = 10 containers

Example 16.1

Number of ContainersNumber of Containers

d = 2000 units/day p = 0.02 day = 0.10w = 0.060.06 day c = 22 units

Westerville Auto Parts

k = 2000(0.06 + 0.02)(1.10)

22

k = 10 containers

Example 16.1

Number of ContainersNumber of Containers

d = 2000 units/day p = 0.02 day = 0.10w = 0.060.06 day c = 22 units

Westerville Auto Parts

k = 2000(0.06 + 0.02)(1.10)

22

k = 10 containers

Example 16.1

Number of ContainersNumber of Containers

d = 2000 units/day p = 0.02 day = 0.10w = 0.060.06 day c = 22 units

Westerville Auto Parts

k = 8 containers

k = 10 containers

Example 16.1

Number of ContainersNumber of ContainersWesterville Auto Parts

d = 2000 units/day p = 0.02 day = 0.10w = 0.060.06 day c = 22 units

k = 8 containers

k = 10 containers

Figure 16.4

Lean Systems in ServicesLean Systems in Services

Consistently high quality Uniform facility loads Standardized work methods Close supplier ties Flexible workforce Automation Preventive maintenance Pull method of materials flow Line flows

Operational BenefitsOperational Benefits Reduce space requirements Reduce inventory investment Reduce lead times Increase labor productivity Increase equipment utilization Reduce paperwork and simple

planning systems Valid priorities for scheduling Workforce participation Increase product quality