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Line balancing

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Definition:

Line balancing is the procedure in which

tasks along the assembly line are

assigned to work station so each has

approximately same amount of work.

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Ford installs first movingassembly line1913

Photo: Moving assembly line atFord Motor ompany!s Michiganplant"n #$%&' (enry Ford announced hisgoal for the Ford Motor ompany:to create )a motor car for the greatmultitude.) *t that time'automobiles were expensive'custom+made machines.Ford!s engineers took the first steptowards this goal by designing theModel ,' a simple' sturdy car'offering no factory options ++ noteven a choice of color. ,he Model,' first produced in #$%-' kept the

same design until the last one ++number #'%%%'%%% ++ rolled off theline in #$/&. From the start' theModel , was less expensive thanmost other cars' but it was still notattainable for the )multitude.)

http://www.pbs.org/wgbh/aso/databank/entries/btford.htmlhttp://www.pbs.org/wgbh/aso/databank/entries/btford.html

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Line 0alancing Problem

,he ob1ective is to assign tasks to

minimi2e the workers3 idle time' therefore

idle time costs' and meet the re4uired

production rate for the line

"n a perfectly balanced line' all workers

would complete their assigned tasks at the

same time 5assuming they start their worksimultaneously6

,his would result in no idle time

. . . more

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Line 0alancing Problem

7nfortunately there are a number of

conditions that prevent the achievement of

a perfectly balanced line,he estimated times for tasks

,he precedence relationships for the tasks

,he combinatorial nature of the problem

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Line 0alancing Problem

8ork stations are arranged so that theoutput of one is an input to the next' i.e.' a

series connection

Layout design involves assigning one or

more of the tasks re4uired to make aproduct to work stations

. . . more

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Example of Line Balancing

9ou3ve 1ust been assigned the 1ob a

setting up an electric fan assembly line

with the following tasks:

Task Time (Mins) Description Predecessors

A 2 Assemble frame None

B 1 Mount switch A

C 3.25 Assemble motor housing None

D 1.2 Mount motor housing in frame A, CE .5 Attach bla!e D

" 1 Assemble an! attach safet# grill E

$ 1 Attach cor! B

% 1.& 'est ", $

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Example of Line Balancing:

Structuring the recedence !iagram'as( )re!ecessorsA None

A

B A

B

C None

C

D A, C

D

'as( )re!ecessors

E D

E

" E

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$ B

$

% E, $

%

/ #

./ #./ %. #

#

#.;

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Line 0alancing Problem

A

B

C

&.1mins

D

1.*mins

E

  2.* mins

"

3.3

mins

$

2.+ mins

2.2 mins

3.& mins

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(ere idle time=#>.-

 idle time ?age=5#>.-@$./6A#%%=#-/.>%?

,his is not acceptable

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 step /+transferability

  in this principle the activities

are transferred from one 2one to another

as long as they don3t affect the se4uence

denoted by ordered pair 

.step + from step / and by arranging thework centres' the lines balancing becomes

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Line 0alancing Problem

A

B

C

&.1mins

D

1.*mins

E

  2.* mins

"

3.3

mins

$

2.+ mins

2.2 mins

3.& mins

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 here idle time=; min

 idle time ?age=5;@>6A#%%=>>.>?

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  thank you