CHAPTER 3
Plant/Facility Layout
1
Definition
• The overall arrangement of machines, departments,
work centers, equipment, material handling, service
facilities and aisles to facilitate the movement of work,
customers or materials through the system.
• Objective of Plant Layout
 Reduce Bottlenecks in moving people or material
Bottleneck – an operation that limits output in the
production sequence. Bottleneck centre has less
capacity than the prior and following work centers.
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 Minimize Material Handling Cost
 Reduce Hazard To Personnel
 Utilize Labor Efficiently
 Increase Morale
 Utilize Available Space Effectively and
Efficiently.
 Provide Flexibility
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1
Factors That Influence Layout
1. Type of product – good of services, the aspect
of product design and quality standard and
whether for stock or made to order products.
2. Volume of production – capacity utilization,
provision for expansion.
3. Type of production process – technology used,
types of material handled and the process of
producing the goods, service creation and
delivery.
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Types of Production/Operation
• Continuous/Flow shop
• Intermittent/Job shop
• Project
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Types of Production
Continuous/Flow shop Intermittent/Job shop
High product volume
Low product volume
Use special purpose equipment
Use general purpose equipment
Capital intensive operations
Labor intensive
Few schedule changes due to few Frequent schedule changes due to
highly standardize output
large variety of outputs
Small product mix
Large product mix
Standardize product made to
inventory
Made to order products and not
stored
Operators are less broadly skilled
Operators are broadly skilled
Fixed cost high and variable cost
low
Fixed costs tend to be low and
variable cost high
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2
Types of Layout
•
1.
2.
3.
3 basic types of layouts
Product layout
Process layout
Fixed layout
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Product Layout
• Product layout is defined as the arrangement of
facilities according to the needs processing
requirement and in the same sequence as the
operations necessary for producing the products
or service.
• Also known as line layout or assembly layout
• It is appropriate for producing one standard
product, in large volume
• Suitable for products that require continuous
production operations. Eg television sets,
washing machines and automobiles assembly.
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Advantages and Disadvantages of
Product Layout
Advantages
Disadvantages
Reduce material handling cost
Lack of process flexibility
Low work in progress inventory
Expensive equipment – special
purpose equipment
Reduced total processing time –
high output, low unit cost
The operation are too
interdependent
Task is simplified – low training
cost and time
Low workers’ morale and
productivity
Simple production planning and
control
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3
Process Layout
• Process layout is the arrangement of facilities and
equipment in groups according to the function
performed.
• It is appropriate for intermittent operations when work
flow is not consistent for all output.
• Variable of workflow occurs when a variety of products
or variations on single product are produced.
• Work centers or department are grouped together
according to functional type
• Prevalent in banks, hospital and department store.
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Process-Oriented Layout
Patient A - broken leg
ER
triage
room
Emergency room admissions
Patient B - erratic heart
pacemaker
Surgery
Laboratories
Radiology
ER Beds
Pharmacy
Billing/exit
Figure 9.3
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Advantages/Disadvantages of
Process Layout
Advantages
Disadvantages
Flexibility of equipment and
personnel
High material handling cost
Smaller investment in equipment
High work in process inventory
Workers are more knowledgeable
Large storage space
Less vulnerable to equipment
failure
Large aisles required
High production cost per unit
Long processing time
Complex requirement for
scheduling and control
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4
Comparison Between Product and
Process Layout
Product layout
Process Layout
Efficiency
Flexibility
Machines are arranged in a
sequence manner
Machines are arranged in groups
according to functions
Continuous production process
Intermittent production process,
jobshop, batch production
Standardize product made to stock Varied, product made to order
Stable demand
Fluctuating demand
High Volume
Low volume
Special purpose equipment
General purpose equipment
Workers have limited skillsperform special tasks
Workers have varied skills –
perform diverse tasks.
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Fixed Position layout
• Fixed position layout is the arrangement of
facilities and equipment so that resources
needed in the form of workers, equipment and
materials flow to the item being produced or
serviced.
• Also referred to as project layout
• Eg. Home plumbing , construction of dams,
bridges, ships and home building.
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Product Layout Analysis
•
Three important requirements in designing an
effective and efficient production line.
1. It meets the required capacity of demand –
able to generate the desired number of output
2. The sequence is technically feasible – in
sequence to facilitate the production flow
3. It is an efficient line – reduce cost of idleness
and increase capacity
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5
Important definitions
Precedence diagram
It shows the elemental task to be
performed and sequence
requirements.
Task time
The amount of time required to
perform a task. Could be in
minutes or seconds.
Productive times per hour
Number in the minutes in each
hour that a work station is working.
Cycle time
The longest task time.
Work station
Physical location where particular
set of task are performed
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Important definitions
Minimum numbers of work stations The least number of workstations
that can provide the required
production.
Actual number of work stations
The total number of workstations
required on the entire production
line, calculated as the next higher
integer value of the number of
workstations working.
Bottleneck station
The workstation that has the
longest task time.
Line balancing
The process of assigning tasks to
workstation in order to equalize
the performance time at all
workstations in such a way that 17
idle time is minimized
Production Layout Analysis
1.
2.
3.
4.
Cycle time
Capacity
Efficiency and Idleness
Assembly Line Balancing
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