Production Sched Large Corp

8/17/2019 Production Sched Large Corp

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Production Planning & Schedulingin Large Corporations:

Dealing with the Complexities of

Product Variety and Structure


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The Maor Sources of Complexity

! " large #ariety of products:

$ %xample : '(M )des*tops+ laptops+ mainframes+ special,purpose

computers+ etc- furthermore+ many models for each of the a.o#e

categories/

$ %xample 0: 1ord )sedans+ S2V3s mini#ans+ truc*s+ etc- again+

many models and #ariations in each category/


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The Maor Sources of Complexity)cont4/! Product structure: "n assem.ly of a num.er of components and su.assem.lies

$ %xample:

! )Des*top/ Computer

$ Mother.oard

5 CP2,card

5 '67 card

5 Modem card

5 Power supply unit

5 Ventilator

5 etc4

$ Monitor

$ 8ey.oard

$ Mouse

$ )other peripherals/

! Some components and su.assem.lies are produced in,house+ and some are

procured from outside4

(ill of Materials )(7M/


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" typical )logical/ 7rgani9ation of the

Production "cti#ity

Raw

Material

& Comp.

Inventory

Finished

Item

Inventory

S+0S+ S+n

S0+ S0+0 S0+m

Assembly Line 1: Produt Family 1

Assembly Line !: Produt Family !

"a#end $perations

Dept4 Dept4 0 Dept4 *

S+i

S0+i

Dept4


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Dealing with the Pro.lem Complexitythrough Decomposition

"ggregate Planning

Master Production Scheduling

Materials e;uirement Planning

"ggregate 2nit

Demand

%nd 'tem )S82/

Demand

Corporate Strategy

Capacity and "ggregate Production Plans

S82,le#el Production Plans

Manufacturing

and Procurement

lead timesComponent Production lots and due dates

Part process

plans

%Plan. or.: 1 year' (ime )nit: 1 month*

%Plan. or.: a +ew months' (ime )nit: 1 wee#*

%Plan. or.: a +ew months' (ime )nit: 1 wee#*

Shop floor,le#el Production Control%Plan. or.: a day or a shi+t' (ime )nit: real,time*


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Technology e;uirements

! %ffecti#e Data Collection and Maintenance6Data 'ntegrity: There is a need

for a monitoring tool that will pro#ide a centrali9ed+ correct and efficient

representation of the system status at any point in time4

$ 'ndustry Solution: Manufacturing %xecution Systems )M%S/

! e4g4+ S"P+ 7racle+ PeopleSoft

! %fficient and Coherent Computeri9ed Planning Tools: There is a need for

a suite of computationally efficient planning tools that will effecti#ely

address the pro.lems arising at the #arious le#els of the decomposition

framewor*+ while maintaining plan consistency across the different le#els4

$ 'ndustry Solution: Product and Supply Chain Planning Software

! e4g4+ '0 Technologies+ (""


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"ggregate Planning


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Product "ggregation Schemes

!'tems )or Stoc* 8eeping 2nits , S823s/: The final products deli#ered to the

)downstream/ customers!1amilies: =roup of items that share a common manufacturing setup cost-

i4e4+ they ha#e similar production re;uirements4!Types: =roups of families with production ;uantities that are determined in

a single aggregate production plan4

!"ggregate 2nit: " fictitious item representing an entire product type4!"ggregate 2nit Production e;uirements: The amount of )la.or/ time

re;uired for the production of one aggregate unit4 This is computed .y

appropriately a#eraging the la.or time re;uirements o#er the entire set of

items represented .y the aggregate unit4!"ggregate 2nit Demand: The cumulati#e demand for the entire set of items

represented .y the aggregate unit4

emar*: (eing the cumulate of a num.er of independent demand series+ the

demand for the aggregate unit is a more ro.ust estimate than its constituent

components4


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Computing the "ggregate 2nitProduction e;uirements

>ashing machineModel


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"ggregate Planning Pro.lem

"ggregate Planning

"ggregate

2nit Demand

"ggregate

2nit "#aila.ility

)Current 'n#entory

Position/

"ggregate

Production Plan

e;uired

Production Capacity

"ggr4 2nitProduction e;s

Corporate Strategy

"ggregate Production Plan:

!"ggregate Production le#els

!"ggregate 'n#entory le#els!"ggregate (ac*order le#els

Production Capacity Plan:

!>or*force le#el)s/

!7#ertime le#el)s/!Su.contracted Juantities


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Pure "ggregate Planning Strategies

4 Demand Chasing: Vary the >or*force Le#el

D)t/ P)t/ H D)t/

>)t/

PC >C KC 1C

!D)t/: "ggregate demand series!P)t/: "ggregate production le#els!>)t/: e;uired >or*force le#els

!Costs 'n#ol#ed:!PC: Production Costs

!fixed )setup+ o#erhead/!#aria.le)materials+ consuma.les+ etc4/

!>C: egular la.or costs

!KC: Kiring costs: e4g4+ ad#ertising+ inter#iewing+ training!1C: 1iring costs: e4g4+ compensation+ social cost


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04 Varying Production Capacity with Constant >or*force:

D)t/ P)t/

7)t/

PC >C 7C 2C

2)t/

S)t/

SC

> H ct!S)t/: Su.contracted ;uantities!7)t/: 7#ertime le#els!2)t/: 2ndertime le#els!Costs in#ol#ed:

!PC+ >C: as .efore!SC: su.contracting costs: e4g4+ purchasing+ transport+ ;uality+ etc4!7C: o#ertime costs: incremental cost of producing one unit in o#ertime

!)2C: undertime costs: this is hidden in >C/


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A4 "ccumulating )Seasonal/ 'n#entories:

D)t/ P)t/

')t/

PC >C 'C

>)t/+ 7)t/+ 2)t/+ S)t/ H ct

!')t/: "ccumulated 'n#entory le#els!Costs in#ol#ed:

!PC+ >C: as .efore!'C: in#entory holding costs: e4g4+ interest lost+ storage space+ pilferage+

o.solescence+ etc4


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B4 (ac*logging:

D)t/ P)t/

()t/

PC >C (C

>)t/+ 7)t/+ 2)t/+ S)t/ H ct

!()t/: "ccumulated (ac*log le#els!Costs in#ol#ed:

!PC+ >C: as .efore!(C: .ac*log )handling/ costs: e4g4+ expediting costs+ penalties+ lost sales

)e#entually/+ customer dissatisfaction


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Typical "ggregate Planning Strategy

" mixture of the pre#iously discussed pure options:

D

PC >C KC 1C 7C 2C SC 'C (C

P>K

172S

'

(

-"dditional constraints arising from the company strategy- e4g4+

!maximal allowed su.contracting!maximal allowed wor*force #ariation in two consecuti#e periods!maximal allowed o#ertime

!safety stoc*s!etc4


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Solution "pproaches

! =raphical "pproaches: Spreadsheet,.ased simulation

! "nalytical "pproaches: Mathematical )mainly linear

programming/ Programming formulations


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Proacti#e approaches todemand management

! 'nfluencing demand #ariation so that it aligns to a#aila.le

production capacity:

$ ad#ertising

$ promotional plans

$ pricing

)e4g4+ airline and hotel wee*end discounts+ telecommunication

companies3 wee*end rates/

! Counter,seasonal product )and ser#ice/ mixing: De#elop

a product mix with antithetic )seasonal/ trends that le#el thecumulati#e re;uired production capacity4

$ )e4g4+ lawn mowers and snow .lowers/


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Modern Trends in"ggregate Planning

! To effecti#ely achie#e the competiti#e ad#antages and economies of scalere;uired in today3s mar*ets+ large corporations must plan and manage their

production acti#ity across the entire supply chain4

! This introduces another spatial6geographical dimension to the

aggregate6capacity planning pro.lem+ and extends the initial cost structure

with additional items li*e transportation and storage6handling costs4! The pro.lem get especially complicated for companies with multinational

operations+ since these companies must factor into their planning

additional issues li*e:

$ duties and tariffs and ;uotas

$ exchange rates

$ local corporate tax rates

$ cultural+ language and political issues


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Master Production Scheduling

)MPS/


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The )Master/ Production Scheduling Pro.lem

MPS

Placed 7rders

1orecasted Demand

Current 'n#entory Positions

"lready 'nitiated Production

Master Production

Schedule:

>hen & Kow Much

to produce for each

product

Capacity

Consts4

Company

Policies

%conomic

Considerations

Product

Charact4

Planning

Kori9on

Time

unit

Capacity

Planning


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The Dri#ing Logic for the %mpirical "pproach

Demand "#aila.ility:

!'nitial 'n#entory Position

!Scheduled eceipts

1uture in#entories


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)Typical/ "nalytical "pproaches to MPS

! ecogni9ing that switching production from item to item)or family to family/ re;uires long set,up times+ duringwhich the effecti#e producti#ity of the line is e;ual to 9ero+these )formal/ approaches try to minimi9e the )long,run/num.er of set,ups while meeting the production needs+ as

expressed .y the aggregate production plan and the currentS82 a#aila.ility4

! %xamples: $ Text.oo*+ pg4 B@

$ %lsayed & (oucher+ "nalysis and Control of Production

Systems )0nd ed4/+ Prentice Kall+ B+ pgs B@,@: (loc*edMaximal Cycle Keuristic4


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Materials e;uirements Planning

)MP/


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The MP %xplosion Calculus

"$M

MP

MP

Current

Availabilities

Planned

$rder Releases

Priority

Plannin/

Lead(imes

Lot i0in/

Poliies


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(ill 7f Materials )(7M/" formal6systematic representation of the product structure and the

assem.ly steps re;uired for its synthesis from its components andsu.assem.lies4

!!

112%3*

114%!*

!2!

%5*

!41

%!*

!21

%1*

!21

%1*

1 units

!Su.assem.ly @: Ax)num.er of F00/ AxFF AFF

!Su.assem.ly : 0x)num.er of F00/ 0xFF 0FF!Component 0@: x)num.er of @/ xAFF

x)num.er of / x0FF @FF

!Component 0@0: Bx)num.er of @/ BxAFF 0FF

!Component 0: 0x)num.er of / 0x0FF BFF


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)Production/ Lead TimesThe expected time inter#al .etween the time that the order for

a new production lot is released+ and the time that the lot is a#aila.le)to .e used in the fa.rication of its parent component/4

Lead times incorporate:!set,up times! processing times

!transfer time!waiting times

!!

1 wee#

112%3*

! wee#s

114%!*

3 wee#s

!2!%5*

! wee#s

!41%!*

1 wee#

!21%1*

1 wee#

!21%1*

1 wee#


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Time,Phased Product Structure

(ime in wee#s

!!617

6!7

637

617

6!7617

617

!12%1*

!2!%5*

!41%!*

!21%1*

112%3*

114%!*

0AB@

% l Ti Ph d


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%xample: Time,PhasedProduction e;uirements

Part ee*

0 A B @ G E Lead Time

F00

@

0@

0@0

0

$rd. Re.

$rd. Re.

$rd. Re.

$rd. Re.

$rd. Re.

$rd. Re.

$rd. Rel.

$rd. Rel.

$rd. Rel.

$rd. Rel.

$rd. Rel.

$rd. Rel.

wee*

0 wee*s

A wee*s

wee*

0 wee*s

wee*

FF

FF

AFF

0FF

AFF

0FF

AFF0FF

AFF0FF

0FF

0FF

BFF

BFF


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=ross e;uirementsThe cumulati#e time,phased demand for a certain part+ integrating the part demand generated from the production plans of its parent

items+ and also+ additional external demand+ arising+ for instance+from the need for spare parts+ inter,plant shipments+ etc4

A

C%!* 8%1*

"

C%1* 9%1*

Item A

Period 1 2 3 4 5 6 7 8 9 10 11 12

NNN4

Planned 7rd4 el4 30

Item "

Period 1 2 3 4 5 6 7 8 9 10 11 12

NNNN

Planned 7rd4 el4 30 75

Item C

Period 1 2 3 4 5 6 7 8 9 10 11 12

=ross e;uirements 12 10 90 75

ervie orderInterplant hipment


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Ta*ing into "ccount theCurrent 'tem "#aila.ility

Item C

Period 1 2 3 4 5 6 7 8 9 10 11 12

=ross e;uirements 12 10 90 75

Scheduled eceipts 20

'n#entory Position: 0F 20 40 40 40 40 28 18 18 -72 0 -75 0


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(7M Le#els!Le#el F: %nd 'tems )S823s/!Le#el : 'tems that constitute components )are children/ of le#el,F

item)s/ only!Le#el 0: 'tems that are children of le#el + and+ potentially+ some

le#el F items only!Le#el i: 'tems that are children of le#el i,+ and+ potentially+ some

le#el F to i,0 item)s/ only

C

"

9 F

>9 C

F 88

C >F9

F9

9

A

Level : A' " Level 1: 8' Level !: C' > Level 3: 9' F


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The MP %xplosion Calculus

Level

Level 1

Level !

Level ;

Initial

Inventories

heduled

Reeipts

9=ternal 8emand

Capaity

Plannin/

Planned

$rder Releases>ross Re


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Capacity Planning )%xample/

Availablelabor

hours

Periods 0 A B @ G E

@F

FF

@F


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%xample: The )complete/ MP %xplosionCalculus

)O4 Kei9er and (4 ender 7perations Management+ Gth %d4 Prentice Kall/

'tem (7M:

"lpha

C)0/D)0/

()/ C)/

%)/

%)/

1)/

1)/

Item Lead Time Current Inv. Pos.

Alpha 1 10

B 2 20

C 3 0

D 1 100E 1 10

F 1 50

Gross Reqs for Alpha

Period 6 7 8 9 10 11 12 13

Gross Res! 50 50 100

'tem Le#els:

Le#el F: "lpha Le#el : ( Le#el 0: C+ D Le#el A: %+ 1


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Production Sched Large Corp