ch11(just-in-time and lean systems)

8/18/2019 Ch11(Just-In-Time and Lean Systems)

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©The McGraw-Hill Companies,

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Chapter 11

Just-in-Time and Lean Systems


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• JIT Defined

• The Toyota Production System

• JIT Implementation Requirements

• JIT in Services

OBJ!TI"S


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Just-In-Time #JIT$

Defined

• JIT can %e defined as an inte&rated set ofactivities desi&ned to achieve hi&h-volumeproduction usin& minimal inventories #ra'

materials( 'or) in process( and finished&oods$

• JIT also involves the elimination of 'aste in

production effort• JIT also involves the timin& of productionresources #i*e*( parts arrive at the ne+t'or)station ,ust in time.$


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JIT and Lean /ana&ement

• JIT can %e divided into t'o terms0 ,Bi& JIT. and

,Little JIT.

• Bi& JIT #also called Lean /ana&ement$ is aphilosophy of operations mana&ement that see)sto eliminate 'aste in all aspects of a firm1sproduction activities0 human relations( vendorrelations( technolo&y( and the mana&ement ofmaterials and inventory

• Little JIT focuses more narro'ly on schedulin&&oods inventory and providin& service resources'here and 'hen needed


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JIT Demand-Pull Lo&ic

Customers

Sub

Sub

Fab

Fab

Fab

Fab

Vendor

Vendor

Vendor

Vendor

Final

Assembly

2ere the customer starts

the process( pullin& an

inventory item from

3inal 4ssem%ly5

2ere the customer starts

the process( pullin& an

inventory item from

3inal 4ssem%ly5

Then su%-

assem%ly 'or) is

pulled for'ard %y

that demand5

Then su%-

assem%ly 'or) is

pulled for'ard %y

that demand5

The process continues

throu&hout the entire

production process and

supply chain

The process continues

throu&hout the entire

production process and

supply chain


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The Toyota Production System

• Based on t'o philosophies0

• 6* limination of 'aste

• 7* Respect for people



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8aste in Operations

6* 8aste from overproduction

7* 8aste of 'aitin& time

9* Transportation 'aste

:* Inventory 'aste

;* Processin& 'aste



/inimi>in& 8aste0

3ocused 3actory

?et'or)s

Coordination

System Integration

These are small speciali>ed

plants that limit the ran&e

of products produced

#sometimes only one type of

product for an entire

facility$

These are small speciali>ed

plants that limit the ran&e

of products produced

#sometimes only one type of

product for an entire

facility$

Some plants in

Japan have as

fe' as 9@ and as

many as 6@@@

employees

Some plants in

Japan have as

fe' as 9@ and as

many as 6@@@

employees



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/inimi>in& 8aste0 Aroup Technolo&y #Part 6$

• sin& Departmental Specialization for plant layout can cause a lot of unnecessary

material movement

• sin& Departmental Specialization for plant layout can cause a lot of unnecessary

material movement

Sa" Sa"

#athe $ress$ress

%rinder

#athe#athe

Sa"

$ress

&eat 'reat

%rinder

?ote ho' the flo' lines are &oin& %ac) and forth?ote ho' the flo' lines are &oin& %ac) and forth



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/inimi>in& 8aste0

Aroup Technolo&y #Part 7$

• Revisin& %y usin& Group Technology Cells can reduce movement and improveproduct flo'

• Revisin& %y usin& Group Technology Cells can reduce movement and improveproduct flo'

$ress

#athe

%rinder

%rinder

A

2

(Sa"

&eat 'reat

#atheSa" #athe

$ress#athe

1



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/inimi>in& 8aste0

niform Plant Loadin& #heiun)a$

)ot uni*orm +an, -nits Feb, -nits .ar, -nits 'otal

1/2!! 3/5!! 4/3!! /!!!

-ni*orm +an, -nits Feb, -nits .ar, -nits 'otal

3/!!! 3/!!! 3/!!! /!!!

Suppose we operate a production plant that produces a singleproduct. The schedule of production for this product could be

accomplished using either of the two plant loading schedules

below.

Suppose we operate a production plant that produces a singleproduct. The schedule of production for this product could be

accomplished using either of the two plant loading schedules

below.

How does the uniform loading help save labor costs?How does the uniform loading help save labor costs?

or



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/inimi>in& 8aste0 Just-In-Time

Production

• Management philosophy• “Pull” system though the plant

WHAT IT IS

• Employee participation• Industrial engineering/asics• !ontinuing impro"ement• Total #uality control• Small lot si$es

WHAT IT %E&'I%ES

• Attac(s )aste• E*poses prolems and ottlenec(s

• Achie"es streamlined production

WHAT IT +,ES

• Stale en"ironment

WHAT IT ASS'MES



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/inimi>in& 8aste0 Inventory

2ides Pro%lems

0or in

proess

ueues

bans

Chaneorders

nineerin desin

redundanies

Vendor

delinuenies

Srap

esin

balos

.ahine

do"ntime

eision

balos

9nspetion

balos

$aper"or

balo

Example !yidentifying defective

items from a vendor

early in the

production process

the downstream wor"

is saved

Example !yidentifying defective

wor" by employees

upstream# the

downstream wor" is

saved

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/inimi>in& 8aste0 Can%an Production

!ontrol Systems

Storage

Part A

Storage

Part AMachine

!enter Assemly

-ine

Material .lo)

!ard signal0 .lo)

$ithdrawal

"anban

Once the Production )an%an isreceived( the /achine !enter

produces a unit to replace the

one ta)en %y the 4ssem%ly Line

people in the first place

This puts the

system %ac)'ere it 'as

%efore the item

'as pulled

The process %e&ins %y the 4ssem%ly Line

people pullin& Part 4 from Stora&e

Production (anan

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Determinin& the ?um%er of Can%ans

?eeded

• Settin& up a )an%an system requires

determinin& the num%er of )an%ans cards #or

containers$ needed

• ach container represents the minimum

production lot si>e

• 4n accurate estimate of the lead time required

to produce a container is )ey to determinin&

ho' many )an%ans are required

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The ?um%er of Can%an !ard Sets

C

S DL

k

541

2ontainer theo* Si:e

sto2 Sa*etytimeleaddurin6demand7;pe2ted

+=

+

=

C

S DL

k

541

2ontainer theo* Si:e

sto2 Sa*etytimeleaddurin6demand7;pe2ted

+=

+=

k = %umber of "anban card sets &a set is a card'

D ( )verage number of units demanded over some time

period

L ( lead time to replenish an order &same units of time asdemand'

S ( Safety stoc" expressed as a percentage of demand

during leadtime

C ( Container si*e

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+ample of Can%an !ard Determination0

Pro%lem Data• 4 s'itch assem%ly is assem%led in %atches of : units

from an ,upstream. assem%ly area and delivered in

a special container to a ,do'nstream. control-panel

assem%ly operation

• The control-panel assem%ly area requires ; s'itch

assem%lies per hour

• The s'itch assem%ly area can produce a container ofs'itch assem%lies in 7 hours

• Safety stoc) has %een set at 6@ of needed inventory

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+ample of Can%an !ard

Determination0 !alculations

3or/75,2

4

521,11

ontainer theo* Si:e

sto Sa*etytimeleaddurindemand;peted

==+

=

+

=

C

S DL

k

3or/75,2

4

521,11

ontainer theo* Si:e

sto Sa*etytimeleaddurindemand;peted

==+

=

+

=

C

S DL

k

Always round up!

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Respect for People

• Level payrolls

• !ooperative employee unions

• Su%contractor net'or)s

• Bottom-round mana&ement style

• Euality circles #Small Aroup Involvement4ctivities or SAI41s$

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Toyota Production System1s 3our Rules1, All "or shall be hihly spei*ied as to ontent/

seuene/ timin/ and outome

2,


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JIT Implementation Requirements0

Desi&n 3lo' Process

• Lin) operations

• Balance 'or)station capacities

• Redesi&n layout for flo'

• mphasi>e preventive maintenance

• Reduce lot si>es

• Reduce setupFchan&eover time

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JIT Implementation Requirements0 Total

Euality !ontrol• 8or)er responsi%ility

• /easure SE!

• nforce compliance

• 3ail-safe methods

• 4utomatic inspection

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Sta%ili>e Schedule• Level schedule

• nderutili>e capacity

• sta%lish free>e 'indo's

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Can%an-Pull• Demand pull

• Bac)flush

• Reduce lot si>es

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JIT Implementation Requirements0 8or)

'ith "endors• Reduce lead times

• 3requent deliveries

•Proect usa&e requirements

• Euality e+pectations

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Reduce Inventory /ore

• Loo) for other areas

• Stores

• Transit

• !arousels

• !onveyors

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Improve Product Desi&n• Standard product confi&uration

• Standardi>e and reduce num%er of parts

• Process desi&n 'ith product desi&n

• Euality e+pectations

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!oncurrently Solve Pro%lems• Root cause

• Solve permanently

• Team approach

• Line and specialist responsi%ility

• !ontinual education

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/easure Performance

• mphasi>e improvement

• Trac) trends

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JIT in Services #+amples$

• Or&ani>e Pro%lem-Solvin& Aroups

• p&rade 2ouse)eepin&

• p&rade Euality

• !larify Process 3lo's

• Revise quipment and Process Technolo&ies

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JIT in Services #+amples$

• Level the 3acility Load

• liminate nnecessary 4ctivities

• Reor&ani>e Physical !onfi&uration

• Introduce Demand-Pull Schedulin&

• Develop Supplier ?et'or)s

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nd o* Chapter 11

ch11(just-in-time and lean systems)

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