Plant Layout

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Plant Layout

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Layout PlanningManufacturing & Services

• Deals with the physical arrangement of various resources that are available in the system with an objective to improve the performance of the operating system thereby providing better customer service.

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Inefficient operations

For Example:

High CostBottlenecks

Changes in the designof products or services

The introduction of newproducts or services

Accidents

Safety hazards

The Need for Layout Decisions

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Changes inenvironmentalor other legalrequirements

Changes in volume ofoutput or mix of

products

Changes in methodsand equipment

Morale problems

The Need for Layout Design (Cont’d)

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Implications of layout Planning

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• Relationship between volume-variety –flow provides crucial input for layout planning.

• As the flow becomes more cumbersome, the type of layout may significantly influence the ability of operations manager to effectively plan.

• Table8.1 of Mahadevan

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Types of Layout

• Process

• Product

• Group Technology

• Fixed Position

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Process Layout - work travels to dedicated process centers

Milling

Assembly& Test Grinding

Drilling Plating

Process Layout

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Gearcutting

Mill Drill

Lathes

Grind

Heattreat

Assembly

111

333

222

444

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111 3331111 2222

222

3333

111

444111

333333333

44444

3333

3322

222

Functional Layout

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-1111 -1111

2222 - 2222

Ass

emb

ly

3333 - 3333

4444 - 4444

Lathe

Lathe

Mill

Mill

Mill

Mill

Drill

Drill

Drill

Heat treat

Heat treat

Heat treat

Gear cut

Gear cut

Grind

Grind

Cellular Manufacturing Layout

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Process Layout

• Arrangement of resources on the basis of the process characteristics of the resources available.

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Process LayoutExamples

• Car servicing

• Hospital-Patient requiring various tests

• Volume low & variety is more

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Product Layout

• The resources are placed to follow exactly the visitation sequence dictated by the product.

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Product layout

• The technique employed for product layout is known as line balancing

• The resources required to achieve desired /targeted production rate.

• Cycle time can be considered as a reciprocal of production rate.

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Product layout

• Plant & machinery layout is designed to cater to continuous flow of Materials.

• Use of mechanisation and automation can be planned.

• Automobile Industry

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Advantages

• Process• Sharing of

specialised and costly equipment

• More flexibility• Less vulnerable to

breakdowns

• Product • Standardised product

and process routing • Operational control is

simpler• High output rate is

possible

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Disadvantages

• Process• Large inventory build

up• Excess material

handling

• Product • Less flexibility due to

dedication of resources

• Possibility of duplicating equipments leading to higher costs.

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Group Technology Layout

• This is philosophy that seeks to exploit the commonality in manufacturing and uses this as a basis for grouping components and resources. This is also known as cellular manufacturing.

• Pioneered by Russians• Mid volume & mid variety scenario• 70% of mfg. industry may fall under this

category)

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Advantages of Cellular Layout

• PPC becomes simpler

• Material handling becomes easier

• Traceability improves

• Employees are able to relate better.

• Helps in implementing SGA, Kaizen an JIT

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Cellular Layout- Examples

• Reliance industries- HDPE & LDPE

• Titan Industry

• ABB( Industrial fans & blowers)

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Fixed Position Layout

• The material remains in a fixed position , but the machinery, tool workmen etc are brought to the material

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Fixed Position Layout

• Employed in large project type organisation

• Example• ISRO• Helicopter• Nuclear engg. Division of BHEL

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• One worker and multiple machine layout

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Layout Design for Services

• Critical factors

• Degree of customer contact

• Line visibility

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Performance Measures

• The most fundamental measure for layout design is the distance travelled by customer order in the system.

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Performance Measures

1. Distance travelled by job in the SF

2. Space utilisation index

3. Matl. Handling costs

4. Lead time of the process

5. Ease of prodn. Control

6. No. of ownership changes

• Kg Mts.

• Rs./month• Hrs per avg. product• Size of progress

chasing staff• No. of times job

changes hand.

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• Automation: Machinery that has sensing and control devices that enables it to operate– Fixed automation– Programmable automation

Automation

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• Computer-aided design and manufacturing systems (CAD/CAM)

• Numerically controlled (NC) machines

• Robot

• Manufacturing cell

• Flexible manufacturing systems(FMS)

• Computer-integrated manufacturing (CIM)

Automation

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Dimension Functional CellularNumber of moves between departments

many few

Travel distances longer shorter

Travel paths variable fixed

Job waiting times greater shorter

Throughput time higher lower

Amount of work in process

higher lower

Supervision difficulty higher lower

Scheduling complexity higher lower

Equipment utilization lower higher

Table 6.3Functional vs. Cellular Layouts

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• Warehouse and storage layouts

• Retail layouts

• Office layouts

Other Service Layouts

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

Design Product Layouts: Line Balancing

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

Cycle Time

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O utput capac ity = O T

C T

O T operating tim e per day

D = D es ired output ra te

C T = cyc le tim e = O T

D

O utput capac ity = O T

C T

O T operating tim e per day

D = D es ired output ra te

C T = cyc le tim e = O T

D

Determine Maximum Output

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N = (D)( t)

OT

t = sum of task times

Determine the Minimum Number of Workstations Required