1 IRWIN a Times Mirror Higher Education Group, Inc. company, 1996 Facilities Layout

1IRWIN

a Times Mirror Higher Education Group, Inc. company, 1996

Facilities Layout

2IRWIN


Basic Layout Types

Product Layouts Process Layouts Fixed-Position Combination Layouts

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Basic Layout Formats

Group Technology Layout

Just-in-Time Layouts– May be assembly-line or – Group Technology formats

Fixed Position Layout– e.g. Shipbuilding

Part Family W Part Family X

Part Family Y Part Family Z

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The Need for Layout Decisions

Inefficient operations

For Example:

High CostBottlenecks

Changes in the designof products or services

The introduction of newproducts or services

Accidents

Safety hazards

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The Need for Layout Designs (Cont’d)

Changes inenvironmentalor other legalrequirements

Changes in volume ofoutput or mix of

products

Changes in methodsand equipment

Morale problems

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Cellular Layouts

Cellular Manufacturing

Group Technology

Flexible Manufacturing Systems

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Basic Layout Types Product Layout (classify by nature of product)

– Layout that uses standardized processing operations to achieve smooth, rapid, high-volume flow

Process Layout (classify by nature of process)– Layout that can handle varied processing requirements

Fixed Position Layout– Layout in which the product or project remains stationary, and workers, materials, and equipment

are moved as needed

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A Flow Line for Production or Service

Flow Shop or Assembly Line Work Flow

Raw materialsor customer

Finished item

Station 2

Station 3

Station 4

Material and/or labor

Station 1




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A U-Shaped Production Line

1 2 3 4

5

6

78910

In

Out

Workers

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Process Layout

Milling

Assembly& Test Grinding

Drilling Plating

Process Layout - work travels to dedicated process centers

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Cellular Layouts

Cellular Manufacturing– Layout in which machines are grouped into a cell that can process items that have

similar processing requirements Group Technology

– The grouping into part families of items with similar design or manufacturing characteristics

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Cellular Manufacturing Layout

-1111 -1111

222222222 - 2222

Ass

embl

y

3333333333 - 3333

44444444444444 - 4444

Lathe

Lathe

Mill

Mill

Mill

Mill

Drill

Drill

Drill

Heat treat

Heat treat

Heat treat

Gear cut

Gear cut

Grind

Grind

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Design Product Layouts: Line Balancing

Line Balancing is the process of assigning tasks to workstations in such a way that theworkstations have approximately equal timerequirements.

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Cycle Time

Cycle time is the maximum time allowed at each workstation tocomplete its set of tasks on a unit.

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Determine Maximum Output

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Determine the number of workstations

The minimum No. of workstations required

=Daily demand total time to finish a unit

Total operating time in one day (per workstation)

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Determine the Minimum Number of Workstations Required: Efficiency

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Rules to solve line-balancing problem

Can be formulated as integer programming problems. The following simple heuristics (intuitive rules) are used for simple problems

1. Assign tasks in order of most following tasks

2. Assign tasks in order of greatest positional weight. Posistional weight is the sum of each task’s time and the times of all following tasks.

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Precedence Diagram

Precedence diagram: Tool used in linebalancing to display elemental tasks

and sequence requirements

A Simple Precedence Diagrama b

c d e

0.1 min.

0.7 min.

1.0 min.

0.5 min. 0.2 min.

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Example 1: Assembly Line Balancing

Arrange tasks shown in the previous slide into workstations.– Use a cycle time of 1.0 minute– Assign tasks in order of the most

number of followers

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Solution to Example 1

W o r k -S t a t i o n

T i m eR e m a i n i n g E l i g i b l e

A s s i g nT a s k

S t a t i o nI d l e T i m e

1 1 . 0. 9. 2

ac

n o n e

ac- . 2

2 1 . 00

bn o n e

b- 0

3 1 . 0. 5. 3

de-

de- . 3

. 5

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Calculate Percent Idle Time

timeidlePercent - 100% Efficiency

timeCycle ons workstatiof No.

cycleper timeIdle timeidle of Percentage

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Example 1

Percentage of idle time = 0.5 / (3 1.0) = 16.7%

Efficiency = 100% - 16.7% = 83.3%

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Solution to Example 2

Station 1 Station 2 Station 3 Station 4

a b ef

d

g h

c

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Interdepartmental Work Flows for Assigned Departments

1 3 2

30

170 100

A B C

Documents

1 IRWIN a Times Mirror Higher Education Group, Inc. company, 1996 Facilities Layout