Product Life Cycle & Ergonomics Guide

PRODUCT LIFE CYCLE &
ERGONOMICS
Design Philosophy
Dr. (Ms.) Jayaruwani Fernando, Ph.D. (Ag. & Biosystems Engineering), M.S. (Industrial
& Ag. Technology), M.Phil. (Ag. & Biosystems Engineering), B.Sc. (Agriculture)

LESSON OUTCOMES
• Describe the product life cycle
• Identify the life cycle assessment framework and importance of LCA
• Identify the strict liability concept
• Define ergonomics
• Describe the importance of ergonomics applications
Dr. (Ms.) Jayaruwani Fernando, Ph.D. (Ag. & Biosystems Engineering), M.S. (Industrial and Ag. Technology), M.Phil. (Ag. & Biosystems Engineering), B.Sc. (Agriculture)

LIFE CYCLE MAINTENANCE
• Product life cycle refers to the length of time a product is
introduced to consumers into the market until it's removed from
the shelves
• This concept is used by management and by marketing
professionals as a factor in deciding when it is appropriate to
increase advertising, reduce prices, expand to new markets, or
redesign packaging
Recognize the need
Problem definition
Gathering of information
Concept generation
Concept selection
Communication
Detailed design and analysis
Prototype Development and
Testing
Manufacturing
Life cycle maintenance

PRODUCT LIFE CYCLE
• A product has a life of its own
and goes through cycles
Traditional product life cycle

LIFE CYCLE ASSESSMENT (LCA)
• LCA - “life cycle analysis”, “eco-balance”, or “cradle to grave analysis”
assess environmental impacts associated with all the stages of a product's life.
• LCA can be used for
• Assist regulators/government in formulating legislation
• Assist manufacturers in analyzing and improve their processes or products
• Enable consumers to make informed choices

Life cycle assessment framework
Goal & scope
definition
Inventory analysis
Impact assessment
Interpretation

GOAL & SCOPE DEFINITION
• Practitioner defines the product system in terms of the system boundaries of the
study and a functional unit
• Functional unit facilitates the direct comparison of alternative goods or services
• FU- a quantity of a product or product system based on the performance it delivers
in its end-use application

INVENTORY ANALYSIS
• Estimating the
• consumption of resources,
• quantities of wastes,
• emissions,
• noise, etc., that are associated with each stage in a product's life cycle
• Material and energy flows are modeled between the processes within a life cycle
• Overall models provide mass and energy balances for the product system, its total inputs
and outputs into the environment, on a per FU basis

IMPACT ASSESSMENT
• provides indicators for the interpretation of the inventory data in terms of
contributions to different impact categories
• facilitate the evaluation of a product, and each stage in its life cycle, in terms of
climate change, noise, land use, water consumption, etc.

INTERPRETATION
• Occurs at every stage of LCA
• Interpretation of a life cycle involves critical review, determination of data sensitivity,
and results presentation
• This is often termed valuation or weighting

MACHINE DESIGNER SKILLS
1. Inventiveness
2. Engineering analysis
3. Engineering science
4. Interdisciplinary ability
5. Mathematical skills
6. Decision making
7. Manufacturing processes
8. Communication skills

SOME ORGANIZATIONS OF INTEREST TO MECHANICAL
ENGINEERS
 Aluminum Association (AA)
 American Iron and Steel Institute (AISI)
 American National Standards Institute (ANSI)
 American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE)
 American Society of Mechanical Engineers (ASME)
 American Society of Testing and Materials (ASTM)
 British Standards Institution (BSI)

ECONOMICS
• Materials and labor – Cost increases annually
• Material processing cost – increasing trend
use of automated machine tools and robots
• The cost of manufacturing a single product will vary from city to city and
from one plant to another
 labor, taxes, and freight differentials
 manufacturing variations

STANDARD SIZES
• The use of standard or stock sizes is the first principle of cost reduction
• Example:
• An engineer specifies an AISI 1020 bar of hot-rolled steel 53 mm square added cost to the product
• If the engineer provides that a bar 50 mm or 60 mm square are preferred sizes, using these
standard sizes the cost can be reduced
• The 53 mm size can be obtained by special order or by machining a 60 mm square, but these
approaches add cost to the product
• To ensure that standard or preferred sizes are specified, designers must have access to stock lists
of the materials they employ
• Although many sizes are usually listed in catalogs, they are not all readily available.
• Some sizes are used so infrequently that they are not stocked. A rush order for such sizes may add
to the expense and delay

PREFERRED SIZES AND RENARD (R-SERIES) NUMBERS
(When a choice can be made, use one of these sizes; however, not all parts or items are available in all the sizes shown in the table)

BREAKEVEN POINT
• When two or more design approaches are compared for cost, the choice between the
two depends on a set of conditions such as
• the quantity of production
• the speed of the assembly lines
• Breakeven point – draw production vs. cost graph and the point corresponding to
equal cost in both design approaches

BREAKEVEN POINT
• The breakeven point for this example corresponds to 50 parts.
• If the desired production is greater than 50 parts, the automatic machine should be used.
Example
Consider there is automatic screw machine
and hand screw machine which produce 25
parts per hour and 10 parts per hour
simultaneously.
Draw production vs. cost graph for both
automatic screw machine and hand screw
machine.

SAFETY AND PRODUCT LIABILITY
STRICT LIABILITY CONCEPT
• The manufacturer of an article is liable for any damage or harm that results because of a
defect.
• It doesn’t matter whether the manufacturer knew about the defect, or even could have
known about it.
Example: Suppose an article was manufactured, say, 10 years ago. And suppose at that time
the article could not have been considered defective on the basis of all technological
knowledge then available. Ten years later, according to the concept of strict liability, the
manufacturer is still liable. Thus, under this concept, the plaintiff needs only to prove that
the article was defective and that the defect caused some damage or harm.

SAFETY AND PRODUCT LIABILITY
• Approaches to the prevention of product liability are perform better engineering analysis
and design, quality control, and comprehensive testing procedures
• Advertising managers often make glowing promises in the warranties and sales literature
for a product
• These statements should be reviewed carefully by the engineering staff to eliminate
excessive promises and to insert adequate warnings and instructions for use

ERGONOMICS
• “Ergonomics is the scientific discipline concerned with the understanding of
interactions among humans and other elements of a system, and the
profession that applies theory, principles, data, and methods to design to
optimize human well-being and overall system performance.” International
Ergonomics Association

FOCUS OF ERGONOMICS
• Interaction between person and the
machine and the designing of the interface
• Interface designs - determines how easily
and safely we can use the machine
• When faced with productivity problems,
ergonomists help to improve the interface
and the interaction between the user and
the machine
• Interactions: H>M, H>E, M>H, M>E, E>H,
and E>M
Simple work system (E-local environment, H-human operator, M-machine)

ERGONOMICS TO IMPROVE SYSTEMS
• Design the user interface to make it more compatible with the task and the user
Eg: In a manual handling task, redesign the interface by adding handles or using lighter or smaller
containers to reduce the load on the musculoskeletal system
• Change the work environment to make it safer and more appropriate for the task
Eg: Work environments can be improved by eliminating vibration and noise and providing better
seating, desking, ventilation, or lighting
• Change the task to make it more compatible with user characteristics
Eg: Change the place of keeping the vegetable crates according to worker physical characteristics
• Change the way work is organized to accommodate people’s psychological, and social needs
Eg: Enable workers to work on their own pace, to reduce the psychophysical stresses of being ‘tied to the
machine’

IMPLEMENTATION OF ERGONOMICS
• Improve the performance of systems by improving human machine interaction
• Eliminate the following aspects from a system:
 Inefficiency
 Fatigue
 Accidents, injuries, and errors-due to badly designed interfaces and excess stress either
mental or physical
 User difficulties
 Low morale and lethargy

MODERN ERGONOMICS
• Earlier times-engineer designed a whole machine
• Nowadays-design is a team effort
• Ergonomists play an important role
• in conceptual phase, detailed design analysis, and prototyping phases
• in evaluating existing products and facilities

CONTRIBUTIONS OF MODERN ERGONOMICS
o Identify, classify, and resolve the design issues involving the human component
o Generate of new concepts for the design and analysis of human-machine systems
o Evaluate of the sociotechnical effects of design options
o Identify the core trends in human and biological science and their effect on system design and
management

Product Life Cycle & Ergonomics Guide

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