This document provides an overview of product and service design. It discusses how product and service design translates customer wants and needs into requirements. It also discusses developing new products/services, quality goals, cost targets, and prototyping. Reasons for redesign include market opportunities/threats. The document also covers value analysis, objectives of design like customer satisfaction and cost, issues like lifecycles and standardization, designing for mass customization, phases of design like idea generation and feasibility analysis, and types of processes like job shop and batch processing.
2. product design is the process of deciding on
the unique characteristics and features of the
company’s product.
3. PRODUCT AND SERVICE DESIGN
What does Product and service
design do?
The various activities and
responsibilities of Product and service
design include
Translate the customer wants and
needs into product and service
requirements
Refine existing products and services
(marketing)
4. PRODUCT ANDSERVICE DESIGN
Develop new products and/or services(
marketing and operation)
Formulate quality goals ( marketing and
operation)
Formulate cost targets (accounting ,finance
and operations)
Construct and test prototype ( marketing ,
operations, engineering)
5. REASONS FOR PRODUCT AND SERVICE DESIGNOR REDESIGN
Product and service design has typically had
strategic implications for the success and
prosperity of an organization .
Organization become involved in Product
and service design or redesign for a variety
of reasons
The main forces that initiate design or
redesign are marketing opportunities and
threats
6. REASONS FOR PRODUCT AND SERVICE DESIGNOR REDESIGN
The factors that give rise to market
opportunities and threats can be one or more
changes
7. VALUE ANALYSIS
Refers to an examination of the function of
parts and materials in an effort to reduce cost
and improve performance of a product.
8. OBJECTIVES OF PRODUCT ANDSERVICE DESIGN
The main focus of Product and service
design is customers satisfaction.
Hence ,it is essential for designers to
understand what the customer wants and
design with that in mind.
Secondary focuses in Product and service
design relate to function, cost, potential
profit, quality, appearance, forecasted value
9. Ease of production, ease of assembly and
ease of maintenance or service.
In general ,design ,operations and marketing
must work closely together ,keeping each
other informed and taking in to account the
wants and needs of the customer.
10. In addition , legal, environmental and ethical
considerations can influence the design
function.
11. OTHER ISSUES IN PRODUCT AND SERVICE
DESIGN
Aside from legal, environmental and ethical
consideration , designers must also take into
account
Products or services life cycles
How much standardization to incorporated
Product or service reliability
12. LIFE CYCLES
Many new product and service go though a
life cycles in terms of demand.
When an item is introduced, it may be
treated as a curiosity
Demand is generally low because potential
buyers are not yet familiar with the item
Many potential buyers recognize that all of
the bugs have probably not been worked out
13. LIFE CYCLES
And that the price drop after the introductory
period
Capacity and processing are design for low
volume
With the passage of time, design
improvements usually create a more
reliable and less costly output.
Demand then grows for these reasons,
14. LIFE CYCLES
And because of increasing awareness of
the product or service
High volume will involve different methods
and contribute to low costs.
At the next stage in the life cycle, product or
service reaches maturity: there are few, if
any, design changes and demand levels off
16. STANDARDIZATION
Standardization is
Extent to which there is absence of variety in
a product, services or process
Standardized products are made in large
quantities of identical items
Standardization carries a number of
important benefits as well as certain
disadvantage
17. STANDARDIZATION
Standardized products are immediately
available to customers
Standardized products mean
interchangeable parts, which greatly lower
the cost of production higher
While increase productivity and making
replacement or repair relatively easy
compared with that of customized
Design costs are generally lower
18. STANDARDIZATION
Another benefit of Standardization is
reduced time and cost to train employees
and reduced time to design jobs.
Lack of Standardization is at times leads to
serious difficulties and competitive struggles
High cost of design changes increases
resistance to improvements
Decreased variety results in less consumer
appeal
19. DESIGNING FOR MASS
CUSTOMIZATION
Companies like standardization because it
enables them to produce high volumes of
relatively low-cost products, albeit product
with little variety
Customers, on the other hand,
Typically prefer more variety , although they
like the low cost.
20. DESIGNING FOR MASS
CUSTOMIZATION
The question for producers is to resolve
these issues without
1) Losing the benefits standardisation and
2) Incurring a host of problems that are often
linked to variety
These include increasing the resource needed
to achieve design variety
21. DESIGNING FOR MASS
CUSTOMIZATION
increasing variety in production process,
which would add to the skills necessary to
produce the products
Causing a decrease in productivity
The answer , at least for some mass
customization, a strategy of producing
standardized goods or services, but
incorporating some degree of customization
22. PHASES IN PRODUCT DESIGN AND
DEVELOPMENT
product design and development generally
proceeds in a series of phases
Idea generation
Product development begins with Idea
generation
Ideals can come from a variety sources.
They can be
23. IDEA GENERATION
Supply chain based
Competitor based
Research based
a Supply chain can be a rich source of ideas.
Customers, suppliers, distributors,
employees, and maintenance and repair
personnel can provide valuable insight.
24. IDEA GENERATION
One of the strongest motivators for new and
improved products or services is competitors'
product and services
by studying a competitors' product and
services and how the competitor operates
Pricing policies, return policies, warranties.
Location strategies etc an organization can
glean many ideals
25. IDEA GENERATION
Some companies purchase a competitor’s
product and then carefully dismantle and
inspect it, searching for ways to improve their
own product, this is called reverse
engineering
26. FEASIBILITY ANALYSIS
Feasibility analysis: entail
marketing analysis(demand),
economic analysis (development cost and
production cost ,profit potential and
Technical analysis, capacity requirements
and availability and the skills needed
27. 2 PRODUCT SPECIFICATIONS
This involves detailed descriptions of what is
needed to meet(or exceed) customer wants
3 process specifications
Once Product specifications have been set,
attention turns to specifications for the
process that will be needed to produce the
product
28. CONT---
Alternatives must be weighted in terms of
cost, Availability of resource, potential profit
and quality
This involves collaboration between
accounting and operations
4 prototype development.
With Product and process specifications
complete,
29. CONT---
One( or a few) units are made to see if
there are any problems With the Product
or process specifications
5 Design review
Make any necessary changes or abandon
involves collaboration among marketing,
engineering, design, accounting and
operations
30. 6 MARKET TEST
A market test is used to determine the extent
of customer acceptance.
If unsuccessful return to the Design review.
This phase is handled by marketing
7 product introduction. Promote the product.
This phase is handled by marketing
8 follow-up evaluation
31. PROCESS SELECTION
Technology
Technology and Technological innovation
often have a major influence on business
organization
Technological innovation refers to the
discovery and development of new or
improved product or services or process for
producing or providing them
32. CONT--
Processes converts inputs into output
Process selection refers to deciding on the
way production of goods or services will be
organized
It has a major implication for capacity
planning, layout of facilities, equipments and
design of work systems
33. Process selection occurs as a matter of
course when new products or services are
being planning.
However ,it also occurs periodically due to
changes in product or equipments , as well
as competitive pressure
34. Forecasting , product or service design and
technological consideration all influence
capacity planning and process selection.
How an organization approaches process
selection is determined by the organization’s
process strategy. Key aspect include
Capital intensity
36. Technology
The application of scientific discoveries to the
development and improvement of product
and services and operations processes
There are different kinds technology.
Operations management is primary
concerned with three technology
37. 1product and service technology is the
discoveries and development of new product
and services.
This is done mainly by researchers and
engineers, who use the scientific approach to
develop new knowledge and translate that
into commercial application
39. PROCESS SELECTION
The three questions bear on Process
selection
1) how much variety in products or services
will the system need to handle
2) what degree of the equipment flexibility will
be needed
3 what is the expected volume of out put
Answers to these questions will serve as a
guide to selecting an appropriate process
40. PROCESS TYPES
There are five basic process types
Job shop
Batch
Repetitive
Continuous and project
41. JOB SHOP
Usually operated in small scale
It is used when low volume
High variety goods or services will be
needed
Process is intermittent
Work includes small jobs, each with
somewhat different processing requirements.
42. BATCH
Batch processing is used when moderate
volume of goods or services is desired and
It can handle a moderate variety in goods or
services
The equipment need not be as flexible as in
job shop, but processing is still intermittent
The skill level of work doesn’t need to be as
high as a job shop because there is less
variety
43. BATCH
In the jobs being processed
Examples of batch systems include bakeries,
which make bread, cakes in batches,
movie theatres, which show movies to
groups(batches) of people and
Airlines , which carry planeloads(batches) of
from airport to airport
45. REPETITIVE
When higher volumes of more standardized
goods or services are needed, Repetitive
processing is used.
The standardized output means only slight
flexibility of equipment is needed
Skill of workers is generally low
Examples of this types of system include
Production line and assembly lines
46. CONTINUOUS
When a higher volumes of non-discrete,
highly standardized output is desired, a
continuous system is used.
These systems have almost no variety
in output and, hence, no need for
equipment flexibility
Worker skill ranges
47. STRATEGIC CAPACITY PLANNING
Capacity refers to upper limit or ceiling
on the load that an operating unit can
handle.
The load might be in terms of the
number of physical units produced (e.g.-
, bicycles assembled) or the number of
services performed (e.g., computers
upgraded per hours)
48. STRATEGIC CAPACITY PLANNING
The goal of Strategic Capacity Planning
is to achieve a match between the long-
term supply capabilities of an
organization and the predicted level of
long-term demand.
Organizations become involved in
Capacity Planning for various reasons.
Among the chief reasons are:
49. REASONS FOR STRATEGIC CAPACITY
PLANNING
Changes in demand
Changes in technology
Changes in environment and
Perceived Threats or opportunities
A gap between current and desired
capacity will result in capacity that is out
of balance.
50. STRATEGIC CAPACITY PLANNING
Overcapacity cause operating costs
that are too high
While under capacity causes
strained resources and possible
loss of customers.
Some basic questions in Capacity
Planning are the following
51. QUESTIONS IN CAPACITY PLANNING
What kind of capacity is needed?
How much is needed?
When is it needed?
The question What kind of capacity is
needed depends on the products and
services that management intends to
produce or provide.
52. QUESTIONS IN CAPACITY PLANNING
Forecasts are key inputs used to
answer questions How much is
needed and when is it needed
53. CAPACITY DECISIONS ARE STRATEGIC
For a number of reasons, Capacity decisions
are among the most fundamental of all the
design decisions that managers must make
Capacity decisions can be critical for an
organization
1) Capacity decisions have real impact on the
ability of the organization to meet future
demand for products or services
54. CAPACITY DECISIONS ARE STRATEGIC
2) Capacity decisions affects operating costs
3) Capacity is usually a major determinant of
initial cost
4) Capacity decisions often involve long-term
commitment of resources and the fact that,
once they are implemented, those decisions
may be difficult or impossible to modify
without incurring major costs
55. CAPACITY DECISIONS ARE STRATEGIC
5)Capacity decisions can affect
competitiveness
6)Capacity affects the ease of management
56. DEFINING AND MEASURING
CAPACITY
No single measure of capacity will be
appropriate in every situation .rather ,the
measure of capacity must be tailored to the
situation.
Commonly used measure of capacity are:
Design capacity
The maximum output rate or service capacity
an operation, process, or facility is designed
for
57. MEASURING CAPACITY
Effective capacity
Design capacity minus allowances such as
personal time, maintenance and scrap
Design capacity is the maximum output rate
achieved under ideal conditions
Effective capacity is usually less than design
capacity owing to realities of changing
product mix, the need for periodic
maintenance of
58. MEASURING CAPACITY
Equipment ,lunch breaks, coffee breaks,
problems in scheduling and balancing
operations and similar circumstances.
Actual output cannot exceed effective
capacity and is often less than because of
machine breakdowns, absenteeism,
shortages of materials and quality problems ,
as well as factors that are outside the control
of the operations managers
59. MEASURING CAPACITY
These different measures of capacity are
useful in defining two measures of system
effectiveness:
Efficiency and utilization
Efficiency=actual output
effective capacity
Utilization=actual output
design capacity
60. MEASURING CAPACITY
Both measures are expressed as
percentages
Given the following information, compute the
Efficiency and the utilization of the vehicle
repair department
Design capacity= 50 trucks per day
Effective capacity= 40 trucks day
Actual output =36 trucks per day
61. DETERMINANT OF EFFECTIVE
CAPACITY
Facilities
The design Facilities, including size and
provision for expansion, is key.
Location factors, such tra.c,distance to
mkt,labour s. energey sources and room for
expansion
Layout, env’ta factors
Product and service factors
Product or service design can have tremendous
influence on capacity.
62. DETERMINANT OF EFFECTIVE
CAPACITY
Process factors
The quantity capacity of a process is an
obvious determinant of capacity
Eg. If the quality of output does not meet
standards , the rate of output will be slowed
by the need for inspection and rework
activities
Productivity also affects capacity
63. Process improvements that increase quality
and Productivity can result in increased
capacity
Human factor
Policy factor
Management policy can affect capacity by
allowing or not allowing capacity options
such as over time, second or third shifts
64. STEPS IN THE CAPACITY PLANNING PROCESS
1. Estimate future capacity requirements
2. Evaluate existing capacity and facilities and
identify gaps
3. Identify alternatives for meeting
requirements
4. Conduct financial analyses of each
alternatives
5. Assess key qualitative issues for each
alternatives
65. 6.Select the alternative to pursue that will be
best in the long term
7.Impement the selected alternative
8. Monitoring results
66. FORECASTING CAPACITY REQUIREMENTS
Capacity planning decisions involve long –
term and short-term considerations
involve long –term considerations relate to
overall level of capacity, such as facility size
involve short-term considerations relate to
probable variations in capacity requirements
created by such things as seasonal, random
and irregular fluctuations in demand
67. FORECASTING CAPACITY REQUIREMENTS
long –term capacity needs require
forecasting demand over a time horizon and
then converting those forecasts into capacity
requirements
Some basic demand patterns that might to
identified by a forecast.
In addition to basic patterns there are more
complex patterns, such as combinations of
cycles and trend
68. FORECASTING CAPACITY REQUIREMENTS
When trends are identified, the fundamental
issues are
1. How long the trend might persist, because
few things last forever and
2. The slope of the trend
If cycles are identified, interest focus on
1) The approximate length of the cycles
2) The amplitude of the cycles(i.e deviation from
the average)
69. CALCULATING PROCESSING REQUIREMENTS
A necessary piece of information is the
capacity requirements of products that will be
processed.
To get this information, one must have
reasonable accurate demand forecasts for
each product and
know the standard processing time per unit
for each product, the number of workdays
per year
70. CALCULATING PROCESSING REQUIREMENTS
And the number of shifts that will be used .
A department works one 8-hours shifts, 250
days a year, and has these figures for usage
of a machine that is currently being
considered.
71. CALCULATING PROCESSING REQUIREMENTS
product Annual
demand
Standard
processi
ng time
per
unit(hr)
Processi
ng time
needed(
Hr)
1 400 5 2,000
2 300 8 2,400
3 700 2 1,400
5,800
72. CALCULATING PROCESSING REQUIREMENTS
Working one 8-hours shifts 250 days a year
provides an annual capacity of 8 *250=2,000
hours per year.
We can see that three of these machines
would be needed to handle the required
volume:
5800 hours = 2.9 machines
2000 hours/machine
73. THE CHALLENGES OF PLANNING SERVICE
CAPACITY
It is important to note that capacity planning
for services can present special challenges
due to its nature of services
Three very important factors in planning
services capacity are
1) The need to be near customers
2) The inability to store services
3) The degree of volatility of demand
74. MAKE OR BUY
Once capacity have been determined, the
organization must be decided whether to
produce a good or provided a service itself,
or to outsource(buy) from another
organization.
Many organizations buy parts or contract out
services, for a variety of reasons.
Among those factors are
1 available capacity
75. MAKE OR BUY
2) Expertise. If a firm lacks the Expertise to
do a job satisfactorily, buying might be a
reasonable alternative
3)quality considerations
4) the nature of demand
5) cost
6) risk. Outsourcing may involve certain
risks. One is loss of control over operations.
76. MAKE OR BUY
Another is the need to disclose proprietary
information
77. DEVELOPING CAPACITY ALTERNATIVES
Aside from the general considerations about
the development of alternatives (i.e .,conduct
a reasonable search for possible
alternatives, take care not over-look
nonquantitative factors),there are other
things that can be done to enhance capacity
management.
78. DEVELOPING CAPACITY ALTERNATIVES
1. Design flexibility in to the system
The long-term nature of many capacity
decisions and the risk inherent in long-term
forecasts suggest potential benefits from
reigning flexible systems.
2. Take stage of life cycle into account.
Capacity requirements are often closely linked
to the stage of life cycle that a service or
product is in
79. DEVELOPING CAPACITY
ALTERNATIVES
At the introduction phase, it can be difficult to
determine both the size of the market and
the organization’s eventual share of that
market.
Therefore, organizations should be careful in
making large and /or inflexible capacity
investments
In the growth phase the overall market may
experience rapid growth.
80. DEVELOPING CAPACITY ALTERNATIVES
In the maturity phase the size of market levels
off, and organizations tend to have stable
market shares
Organizations may still be able to increase
profitability reducing costs and making full use
capacity
However, some Organizations may still try to
increase profitability by increasing capacity if the
believe this stage will be fairly long, or the cost
to increase capacity is relatively small.
81. DEVELOPING CAPACITY ALTERNATIVES
In the decline phase Organization is faced
with underutilization of capacity due to
declining demand
Organizations may eliminate the excess
capacity by selling it or by introducing new
products or services.
An option that is sometimes used in
manufacturing is
82. DEVELOPING CAPACITY ALTERNATIVES
To transfer capacity to a location that has
lower labour costs, which allows the
Organization to continue to make a profit on
the product for a while longer.
3 take a ‘’big-picture’’(i.e. systems) approach
to capacity changes.
When Developing capacity alternatives , it is
important to consider how parts of the
system interrelate.
83. DEVELOPING CAPACITY ALTERNATIVES
For example ,when making a decision to
increase the number of rooms in a motel,
one should also take into account probable
increased in demand for parking,
entertainment, and food, housekeeping. This
is a ‘’big-picture’’ approach
The risk in not taking a big-picture approach
is that the system will be unbalanced.
84. DEVELOPING CAPACITY ALTERNATIVES
Evidence of unbalanced system is the existence
of a bottleneck operation.
A bottleneck operation is an operation in a
sequence of operations whose capacity lower
than the capacities in other operations in the
sequence
As a consequence, the capacity of the
bottleneck operation limits the system capacity.
The capacity of the system is reduced to the
capacity of the bottleneck operation .
85. DEVELOPING CAPACITY ALTERNATIVES
4. prepare to deal with capacity ‘’ chunks’’
Capacity increases are often acquired in
fairly large chunks rather than smooth
increments, making it difficult to achieve a
match between desired capacity and feasible
capacity
For instance, the desired capacity of a
certain operation maybe 55 units per hour,
but
86. DEVELOPING CAPACITY ALTERNATIVES
Suppose that machines used for his
operation are able to produce 40 units
per hour each
One machine by itself would cause
capacity to be 15 units per hour short of
what is needed
But two machines would result in an
excess of capacity of 25 units per hour
87. DEVELOPING CAPACITY
ALTERNATIVES
5 attempt to smooth out capacity requirements.
Unevenness in capacity requirements also
create certain problems
6 Identify the optimal the operating level
Production units typically have an ideal or optimal
level operation in terms of unit cost of output.
At the ideal ,cost per unit is the lowest for that
production unit
88. EVALUATING ALTERNATIVES
Cost –volume analysis. manager has the
option of purchasing one, two, or three
machines. fixed cost and potential volumes
are as follows
Num of total annual
corresponding
Machines fixed costs range of
o/t
1 $9600 0 to 300
2 15,000 301to 600
89. EVALUATING ALTERNATIVES
Variable cost is $10 per unit and revenue is
$40 per unit
A)Determine the break even point for each
range
B)if the projected annual demand is between
580 and 660 units, how many machines
should the manager purchase
90. FACILITY LOCATION & LAYOUT
Layout refers to the configuration of
departments, work centers ,and equipment ,
with particular emphasis on movement of
work(customers or materials) though the
system.
As in other areas of system design, layout
decisions are important for three basic
reasons
91. FACILITIES LAYOUT
1) They require substantial investments of
money and effort
2) They involve long term commitments, which
makes mistakes difficult to overcomes
3) They have a significant impact on the cost
and efficiency of the operations
92. FACILITIES LAYOUT
The need for layout planning arises both in
the process of designing new facilities and in
redesigning existing facilities
The most common reasons for redesign of
layouts include inefficient operations (e.g
high cost, bottlenecks),accidents or safety
hazards,
Changes in the design of products or
services
93. FACILITIES LAYOUT
Introduction of products or services
Changes in the volume of output or mix
Changes in methods or equipments
Changes in environmental or other legal
requirements and
Morale problems ( e.g lack of face to face
contact)
94. FACILITIES LAYOUT
Poor layout design can adversely affect
system performance.
The basic objective of layout design is to
facilitate a smooth flow of work, material ,and
information through the system .
Supporting objectives generally involve the
following
95. FACILITIES LAYOUT
To facilitate attainment of products or services
quality
To use workers and space efficiently
To avoid bottlenecks
To minimize material handing cost
To eliminate unnecessary movement of workers
or materials
To minimize production time or customer service
time
To design for safety
96. FACILITIES LAYOUT
The Three basic types of layout are
Product
Process and
Fixed-position
Product layouts are most conducive to repetitive
processing
Process are used for intermittent Processing
and Fixed-position are used when projects
require layout.
97. REPETITIVE PROCESSING: PRODUCT LAYOUTS
is one in which equipment or work
processes are arranged according to the
progressive steps by which the product is
made.
Product layouts are used to achieve a
smooth and rapid flow of large volumes of
goods or customers through a system.
98. REPETITIVE PROCESSING: PRODUCT LAYOUTS
This is made possible by highly standardized
goods or services that allow highly
standardized , repetitive processing.
The work is divided into a series of
standardized tasks, Permitting specialization
of equipment and division of labour.
99. REPETITIVE PROCESSING: PRODUCT LAYOUTS
In manufacturing environments, the lines are
referred to as production lines or assembly
lines
production lines : standardized layout
arranged according to a fixed sequence of
production tasks.+
100. REPETITIVE PROCESSING: PRODUCT LAYOUTS
Product layouts achieve a high degree of
labour and equipment utilization , which
tends to offset their high equipment costs .
Because items move quickly from operation
to operation, the amount of work-in-process
is often minimal
Consequently ,operations are so closely tied
to each other that the entire system is highly
vulnerable to being shut-down because of
101. REPETITIVE PROCESSING: PRODUCT LAYOUTS
Mechanical failure or high absenteeism
Eg. Automobile assembly
fast-food restaurants
The main advantage of Product layouts are
1. a high rate of output
2. Low unit cost due to high volume.the high
cost of specialized equipment is spread
over many units
102. REPETITIVE PROCESSING: PRODUCT LAYOUTS
Labour specialization, which reduces training
costs and time ,and results in a wide span of
supervision
Lower material –handling cost per unit
High utilization of labour and equipment
103. REPETITIVE PROCESSING: PRODUCT LAYOUTS
The primary disadvantages of product
layouts include the following
Poor skilled workers may exhibit interset in
maintaining equipment or in the quality
output
The system is fairly inflexible in response to
changes in the volume of the output or
changes in product or process design
104. REPETITIVE PROCESSING: PRODUCT LAYOUTS
The system is highly susceptible to shutdown
caused by equipment breakdowns or
excessive absenteeism because work
stations are highly interdependent
105. NON- REPETITIVE PROCESSING
:PROCESS LAYOUTS
process layouts are designed to process
items or provide services that involve a
variety of processing requirements.
The variety of jobs that are processed
requires frequent adjustments to equipment
This causes a discontinuous workflow, which
is referred to as intermittent processing
106. NON- REPETITIVE PROCESSING
:PROCESS LAYOUTS
The layouts feature departments or
other functional groupings in which
similar kinds of activities are performed
A manufacturing example of a process
layout is the machine shop, which has
separate departments for milling
,grinding ,drilling , and so on.
107. NON- REPETITIVE PROCESSING :PROCESS
LAYOUTS
process layouts are quite common in
service environment
Because equipment in a process layout
is arranged by type rather than by
processing sequence , the system is
much less vulnerable to shut down
caused by Mechanical failure or
absenteeism
108. ADVANTAGES AND DISADVANTAGES
The Advantages of process layouts include
the following
The system can handle a variety of
processing requirements
The system are not particularly vulnerable to
equipment failures
General-purpose equipment is often less
costly than the specialized equipment used
in product layout and is easier and less
costly to maintain
109. DISADVANTAGES
In process inventory can be high if batch
processing is used in manufacturing
systems
Equipment utilization rates low
Material handling is slow
110. FIXED –POSITION LAYOUTS
In Fixed –position layouts, the item being
worked remains stationary , and workers,
materials, and equipments are moved as
needed.
111. DESIGNING PRODUCT LAYOUTS: LINE
BALANCING
The goal of a product layout is to arrange
workers or machines in the sequence that
operations need to be performed.
The sequence is referred to as a production
line or as assembly line
These lines range from fairly short , with just
a few operations, to long lines that have a
large number of operations
112. LINE BALANCING
Line balancing
The process of assigning tasks to
workstations in such a way that the
workstations have approximately equal time
requirements
The goal of Line balancing is to obtain task
groupings that represent approximately
equal time requirements. This minimizes the
idle time along the line and result in high
utilization
113. LINE BALANCING
Of labour and equipment.
Idle times occurs if task times are not equal
among workstations; some stations are
capable of producing at higher rates than
others.
How does a manager decide how many
stations to use?
The primary determinant is what the line’s
cycle time will be?
114. LINE BALANCING
The cycle time is the maximum time allowed
at each work station to perform assigned
tasks before the work moves on.
The cycle time also establishes the output
rate of a line
For instance, if The cycle time is two
minutes , units will come off the end of the
line at the rate of one every two minutes
115. LINE BALANCING
Suppose that the work required to fabricate a
certain product can be divided up into five
elemental tasks, with the task times and
precedence relationships as following
diagram
The task times govern the range of possible
cycle times.
0.1 m
0.7m 1m 0.5m 0.2m
116. LINE BALANCING
The minimum cycle time is equal to the
longest task time ( 1 minute) and
The maximum cycle time is equal to the sum
of task times ( 0.1+0.7+1+0.5+0.2=2.5
minutes)
Output rat= operating time per day
cycle time
117. LINE BALANCING
Assume that the line will operate for eight
hours per day( 480 minutes) .with a cycle
time of 1 minute, output would be
480 minutes per day =480 units per day
1 minute per unit
With a cycle time of 2.5 minutes, output would
be
480 minutes per day =192 units per day
2.5 minutes per unit
118. LINE BALANCING
Assuming that no parallel activities are to be
employed ( e.g.. two lines ), the output
selected for the line must fall in the range of
192 units per day to 480 units per day
As a general rule , the cycle time determined
by desired output, that is, a desired output is
selected ,and the cycle time is computed.
119. LINE BALANCING
If the cycle time does not fall b/n maximum and
minimum bounds, the desired output rate must
be revised.
cycle time= operating time per day
desired output rate
E.g. , suppose that the desired output rate is
480 units
480 minutes per day= 1 minute per unit
480 units per day
120. LINE BALANCING
The number of workstations that will be
needed is a function of both the desired
output rate and our ability to combine
elemental tasks into workstations
We can determine the theoretical minimum
number of workstations necessary to provide
a specified rate of output as follows:
121. LINE BALANCING
N min = t
cycle time
where
N min= the theoretical minimum number of
stations
t =sum of task times
122. LINE BALANCING
Suppose the desired rate of output is the
maximum of 480 units per day.( This will
require a cycle time of 1 minute.)
The minimum number of stations required to
achieve this goal is
N min= 2.5 minutes per day unit = 2.5
stations
1 minute per unit per station
123. LINE BALANCING
Because 2.5 stations is not feasible, it is
necessary to round up to three stations
A very useful tool in line balancing is a
precedence diagram
A simple precedence diagram
0.1 min 1min
0.7min 0.5min 0.2 min
a
b
c d
e
124. LINE BALANCING
The general procedure in line balancing is
described as follows
1 determine the cycle time and the minimum
number of workstations
2 make assignments to workstations in
order , beginning with station 1 .tasks are
assigned to workstations moving from left to
right through the precedence diagram
125. LINE BALANCING
3 )before each assignment, use the following
criteria to determine which tasks are eligible
to be assigned to a workstation:
A) all preceding tasks in the sequence have
been assigned
B) the task time does not exceed the time
remaining at the workstation.
If no tasks are eligible ,move on to the next
workstation
126. LINE BALANCING
4) after each task assignment, determine
the time remaining at current workstation by
subtracting the sum of times tasks assigned
to it from the cycle time
5) break ties that occur using one of these
rules
A) assign the task with longest task time
B) assign tasks with the greatest number of
followers
127. LINE BALANCING
6) continue until all tasks have been
assigned to workstations
7) compute the appropriate measures( e.g.
percent idle time, efficiency ) for the set of
assignments.
128. LINE BALANCING
Two widely used measures of effectiveness
are
1) percentage of idle time of the line.
This is sometimes referred to as the balance
delay
percentage of idle time=idle time per cycle x
100
N actual x cycle time
where
N actual= actual number of station
129. LINE BALANCING
percentage of idle time = 0.5 x 100
=16.7%
3x1
2) the efficiency of the line .this is
computed as follows
Efficiency=100% - percent idle time
Efficiency=100% -16.7%=83.3%
130. LINE BALANCING
Using the following information contained in
the table shown, do each of the following
1. Draw a precedence diagram .
2. Assuming an eight-hour workday, compute
the cycle time needed to obtain an output
of 400 units per day.
3. Determine the minimum number of
workstations required
131. LINE BALANCING
4 assign tasks to workstations using this rule
: assign tasks according to greatest
number of following tasks. In case of a
tie,use the tiebreaker of assigning the task
with the longest processing time first.
132. LINE BALANCING
task Immediate follower Task time (in minutes)
A B 0.2
B E 0.2
C D 0.8
D F 0.6
E F 0.3
F G 1
g H 0.4
h End 0.3