just-in-time. waste is ‘anything other than the minimum amount of equipment, materials, parts,...

Just-in-timeJust-in-time

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

© 1995 Corel Corp.

Management philosophy of continuous and

forced problem solving

Supplies and components are ‘pulled’ through

system to arrive where they are needed when

they are needed.

What is Just-in-Time?What is Just-in-Time?

THE APPLICABILITY OF JITTHE APPLICABILITY OF JIT

System characteristics for a good fit:– demand is reasonably stable– high-volume repetitive systems making standardized

product-service bundles Requires cooperation and coordination of

employees and suppliers– Continuous improvement and employee involvement

are core aspects– Cellular manufacturing arrangement is ideal

characteristic of JIT suppliers

Push versus PullPush versus Pull

Push system: material is pushed into

downstream workstations regardless of

whether resources are available

Pull system: material is pulled to a

workstation just as it is needed

Streamlined ProductionStreamlined Production

Customers

Flow with JIT

Suppliers

Customers

Material(water in stream)

Traditional Flow

Suppliers

Production Process (stream of water)

Inventory (stagnant ponds)

SuppliersSuppliers

Preventive Preventive MaintenanceMaintenance

LayoutLayout

InventoryInventory

SchedulingScheduling

QualityQuality

Employee Employee EmpowermentEmpowerment

JIT

Just-in-Time Success FactorsJust-in-Time Success Factors

Suppliers– reduced number of vendors– supportive supplier relationships– quality deliveries on time

JIT Contribution to Competitive AdvantageJIT Contribution to Competitive Advantage

Inventory– small lot sizes– low setup times– specialized bins for holding set number of parts

Scheduling– zero deviation from schedules– level schedules– suppliers informed of schedules– Kanban techniques

JIT Contribution to Competitive Advantage - JIT Contribution to Competitive Advantage - continuedcontinued

Customer orders 10

Lot size = 5

Lot 1 Lot 2

Lot size = 2Lot 1 Lot 2 Lot 3 Lot 4 Lot 5

Reducing Lot Sizes Increases the Reducing Lot Sizes Increases the Number of LotsNumber of Lots

……Which Increases Inventory CostsWhich Increases Inventory Costs

Lot Size

Cost

Holding CostTotal Cost

Setup Cost

Optimal Lot Size

SmallerLot Size

……Need to reduce setup costNeed to reduce setup cost

Lot Size

Cost


Setup Cost

Optimal Lot Size

New optimalLot Size

……Need to reduce setup costNeed to reduce setup cost

Lot Size

Cost


Setup Cost

Optimal Lot Size

New optimalLot Size

New Total Cost

Steps to Reduce Setup TimeSteps to Reduce Setup Time

Initial Setup Time

Separate setup into preparation, and actual setup, doing as much as possible while the

machine/process is running (save 30 minutes)

Move material closer and improve material handling (save 20

minutes)Standardize and improve tooling

(save 15 minutes)

90 min

60 min

45 min

25 min

15 min

Use one-touch system to eliminate adjustments

(save 10 minutes)

Training operators and standardizing work procedures (save 2

minutes)

Step 1

Step 2

Step 3

Step 4

Step 513 min

A

A A B B B C

JIT Small Lots

Large-Lot Approach

Time

Time

A A B B B C

A A A B B B B B B C C

JIT produces same amount in same time if setup times are lowered

Small versus Large LotsSmall versus Large Lots

Small lots also increase flexibility to meet customer demands


Preventive Maintenance– scheduled– daily routine– operator involvement

Quality Production– statistical process control– quality by suppliers– quality within firm


Employee Empowerment– empowered and cross-trained employees– few job classifications to ensure flexibility of

employees– training support

Commitment– support of management, employees, and

suppliers

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

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

How many Kanban containers?How many Kanban containers?

ainerSizeOfCont

kSafetyStocmandLeadTimeDenbansNumberOfKa

dDailyDemanLeadTimemandLeadTimeDe *

How many Kanban containers?How many Kanban containers?

Lead time – time between placement of an

order and receipt of an order.

Lead time demand – the demand that occurs

during the lead time

Safety stock – extra stock to allow for

uneven demand.

Westerville Auto Parts CompanyWesterville Auto Parts Company

Westerville Auto Parts produces rocker-arm assemblies for use in the steering and suspension systems of 4-WD trucks. The daily expected demand is 2000. A Kanban container holds 22 assemblies. The lead time to produce a container of parts is 0.08 days. The safety stock is 16 assemblies. How many Kanbans are required?

Number of ContainersNumber of ContainersWesterville Auto Parts

Demand = 2000 units/day Safety stock = 16

Lead time = 0.08 days Container Size = 22


ainerSizeOfCont





ainerSizeOfCont


22

1608.0*2000 nbansNumberOfKa




ainerSizeOfCont


8nbansNumberOfKa



Lean manufacturingLean manufacturing

Just-in-time manufacturing with Kanban approach Production smoothing in the schedule Reduce set-up time Line balance by standardizing operations Machine layout and multi-functional workers for

flexible production Continuous improvement/employee involvement Quality

Can Boeing Make Lean Can Boeing Make Lean Manufacturing Fly?Manufacturing Fly?

http://www.boeing.com/news/releases/2006/q4/061107b1_pr.html

Can Boeing Make Lean Can Boeing Make Lean Manufacturing Fly?Manufacturing Fly?

How has lean manufacturing affected the line-workers?

Explain the statement: “Provided it [Boeing] can sell the philosophy to its workers.”

What has Boeing implemented on the Long Beach assembly line besides the ‘moving’ plane?

How has the supplier behavior changed? What is the role of the ‘water-spiders’?

just-in-time. waste is ‘anything other than the minimum amount of equipment, materials, parts,...

Documents

setup cost lot size

lot size2 slide

time slide

inventory costs lot

time jit contribution

competitive advantage

actual setup

average inventory