Dr. Anagha's Guide to Product Design

Unit I
 Introduction to Product design, Man machine dialog
and Industrial design
 user-centered design, five elements of successful design
 cognition, ergonomics, utility, image, ownership
 Packaging and factors
 design for manufacture, assembly and disassembly
 wiring, temperature, vibration and shock. Safety
 noise, energy coupling,
 grounding, filtering and shielding.
2
Electronic Product Design Unit I as per BE E & TC SPPU syllabus by Dr. Anagha P. Khedkar

Introduction to product design &
product life cycle
 Product design and development : Systematic efforts
 Systems engineering- systematic approach and set of
methods for solving complex problems.
 Systems engineering – provides a framework to
develop product
 Product development path : concept, design, test,
delivery, upto documentation and finally disposal
 Result- best product at lowest cost
3
Electronic Product Design Unit I as per BE SPPU
syllabus by Dr. Anagha P. Khedkar

Flowchart: Aspects of systems
engineering
4

Product Life Cycle (PLC)
 It is the course that a product sales & profits
take over its lifetime.
 It shows the stages that products go through
from development to decline from the market.
 Phases of PLC: Product development,
Introduction/launch, growth, maturity, decline
5

Product development: Constraints
 Functionality: does the product fulfill the need?
 Cost : Is cost as low as possible?
 Safety : Is product safe enough?
 Reliability: how long will it function?
 Maintainability: how easy is it to fix?
 Utility: How easy is it to use?
 Time: how long will it take to develop?
6

Constraints
 Constraint forces to measure both the progress of
development and conformance to the requirements.
 Within such constraints, a product passes through a
life cycle.
7

Concept development
 Define the problem.
 Understand the problem.
 Find out what, where, who, when of problem
 Before definition,
 customer objectives
 User needs
 Regions of operation
 Constraints
 Regulations and standards
8

Customer requirements
 Culture of customer
 Corporate, social, economic, political etc.
 Requirements define What of the system but not how.
9

Identifying the customer
requirements
 Product development typically starts by
 identifying-
 – what the customer wants
10

Identifying the customer
requirements
 Understand the requirement: Marketing or
sales person should understand the customer
requirement thoroughly.
 Proper solution : Large number of meetings are
conducted to correctly understand the process and arrive at
a proper solution.
 A proper solution is the one that is techno-commercially
acceptable to both buyer and supplier of the product
11

Outline of requirements
 General Types:
1. Performance: range, speed, throughput, resolution,
size, weight,power consumption, EMI
2. Reliability & maintainability:mean time betn failures,
failure rate
3. Human factors & user interface: response latency, ease
of use, expertise required
4. Safety & failure mode: hazard analysis
5. Operational regimes & environment: temp. extremes,
stress range, location, duty cycle
12

Requirements : refinement
13

Requirements to specifications
 Customer’s requirement must be
correctly translated in to the technical
specification of a product.
 SRS document
 SDS document
14

Designing the product
• It indicates how of the design?
 Various approaches to design
 Designed to specifications
– paper design
– prototyping with acceptable method(s),
– development of R & D prototype
• R & D prototype is thoroughly tested for technical
and functional specifications
• Field trials
• May requires some design modifications
15

Engineering prototype
 To validate the design, do rapid prototyping/field
testing
 Rapid prototyping – short duration
 Useful for human interface aspects (ease of use,
response latency)
 Field testing – longer duration
 Breadboard evaluation of ckts – falls between rapid
prototyping & field testing
16

Validation, Verification &
Integration
 Validation: determines how well the requirements suit
the intent of system.
 Verification: evaluates how well the system satisfies
the requirements.
 Integration: process of assembling the components &
subsystems & performing the acceptance tests of
validation & verification.
 Integration & Testing determines how well the
solution fits the requirements.
17

Production
 Once the field trials are over (Satisfying the Design
Engineer),
 Product Documentation is prepared & handed
over to production department
 Production department will undertake the
making of a small batch of units (typically
5 units)
 This batch is known as Pilot Production Batch.
18

Pilot Production Batch
 Pilot Production Batch
 The main purpose of making a pilot
product batch is to weed-out marginal
design problems.
 MARGINAL DESIGNS WILL FAIL IN THE FIELD.
19

Quality Assurance (QA) testing
 Once the production department and
R & D are sure of the design meeting the
specification
 Quality Assurance department test results data on
pilot batch units.
 They are the final authority to declare the
product has passed all the tests
 Periodically random checks performed on products.
20

Reliability
 Reliability is the probability that a system
will perform its specified function in a given
environment
 quality over time and environmental conditions
 The reliability definition emphasizes
 – Probability,
 – Intended function
 – Time and Operating Conditions.
21

Failures
 A failure is the partial or total loss or change in
those properties of a device or system in such a way
that its functioning is seriously affected or completely
stopped.
 Investigating failure mechanisms helps in
increasing the reliability of the designed product.
22

Causes of failure
 Components used have incorrect resistance,
impedance, voltage, current, capacitance, or dielectric
properties. These are called as-Electrical Overstress
(EOS) failures.
 Due to improper shielding for EMI or due to
Electrostatic Discharge (ESD).
 Improper Thermal Management causes thermal
Failures.
23

Completion of product
development
 Launching the product
 Monitoring its growth, profit and duration
 Checking maintenance aspects
 Observing product decline in the market
 disposal
24

Conclusion
 Development phases of product
 Need to consider all aspects carefully in each phase for
better design and development.
 Importance : testing, failure mechanisms, reliability
 Product life cycle.
25

Man M/C dialogue and Industrial
Design
 Dialogue: human interface of product(HMI)
 Defines: user’s view, set of interactions, understanding
of instrument
 Affects entire design of product
 It is communication and establishes the message and
dialogue.
26

Industrial design
 Multidisciplinary process – uses many concepts to
refine the design of human interface.
 It involves:
 Design team: engineers(h/w, s/w), graphic designers,
model makers
 Stakeholders: end users, customers, influencers
 Repeated discovery, development & delivery
 Designer and user view- may differ
 Integrate users into design process to understand their
needs, wants & desires.
27

User interface
 Define carefully the interface before
 Code is written & ckts are designed/packages are built.
28

User Centered Design
 Successful design – understanding users
 Involve users in design process
 Website visits, resident knowledge, user profile, focus
groups, concept descriptions
 Capabilities & expectations of end users/customers
 Start with the needs of user.
 Consider interface design seriously as an independent &
imp. Problem.
 Users, Influencers & Customers
 User-operator of device, customer-purchaser, influencer-
control over purchase & use
29

User interface: prescription &
process
 Purpose of device
 Prescription: what should be done-serve user
 Process: how it is done
 Elements of user interface:
 Analyze user needs.
 Specify:
 Performance requirements
 Tasks
 Methods to do task
 Design for error recovery
30

Analysis
 Refinement of HMI needs analysis as:
 Task analysis- get to know potential users
 Questionnaires
 Informal & formal interviews
 Focus groups
 Alpha test sites
 Beta test sites.
31

User centered design: rapid
prototyping & field testing
 Rapid prototyping & field testing: interaction between
designer & user
 Essential in successful product development
 Users cannot accurately describe operational
requirements.
 Testing by real operators in operational environment
 Rapid prototyping : alpha test sites
 Field testing: beta test sites
32

5 elements of successful design
 Elements contributing to good design:
 Cognition
 Ergonomics
 Utility
 Image
 Ownership
 Elements define user interface & ensure a useful &
functional dialogue.
33

 Cognition: mental tasks & computations involved in
operating device, relates to expectations of device.
 Ergonomics: concerns of human factors.
 Utility: measures ease of use, imp. for a product in
competitive market.
 Image: user’s perception of product & its operation.
 Ownership: level of commitment a user exercises to
use your product
34

35

 Users want to understand product & control over
events
 Remote control for TV, VCR
 People never learn to use full range of functions
36

Cognition
 Aspects: learning, memory, organization, consistency
 Learning: by user
 Provide incremental instructions for inexperienced
users
 Use short cuts around simple operations
 Give users relevant context so that they can choose next
steps.
 Use examples in instruction
 GUI-Icons, windows, menus, buttons, knobs etc.
 (desktop PC user interface- power, headphone, mic,
USB interface) )
37

Cognition : memory
 Memory recall : ease of use
 Simplify amount, content, structure.
 User’s short term memory connects one event to next
during interface dialogues.
 Don’t require user to remember long sequences of
operations
 Memory recall-recall directed searches (expert user) &
recognition based scanning (infrequent user)
 Response latency of interface: not too long
38

Cognition : Organization
 It puts information where users expect to see.
 Organization: simple, concise , few components
 Categorical menus preferred over alphabetical
/random organization
 Avoid too many colours, windows, character sizes
 Organize menu according to user
39

Cognition : consistency
 Consistency should be in form, colour, operation –
acceptance by user
 Reduces training time
 User capabilities:
 User experience
 Frequency of use
 Occasional users
 Professional & personal preferences of user
40

Cognition : consistency
 Each user forms a mental model of
instrument/product.
 More functionality: more ease of learning: decided by
degree of consistency of use between different
functional domains.
41

Ergonomics
 Relates to human factors.
 Concerned with Physical layout of interfaces.
 It focuses on accessibility, arrangement & fit to make
product usable.
 Need to collect ergonomic data.
 This data provide starting point or base for interface
design.
42

Ergonomics
 Anthropometric data: statistics on size, weight, other
physical parameters.
 anthropology : the science of human beings;
especially : the study of human beings and their
ancestors through time and space and in relation to
physical character
 Capability of human population vary with age, size,
M/F, mobility, training, experience (smart phone use)
 Statistics constrain physical dimensions of a work
place.
43

Ergonomics
 Workplaces
 Lighting
 Cues: are indicators of function.
(visual/auditory/tactile-size,shape,force,texture)
44

Ergonomics: workplaces
 Product may be used in wide variety of situations.
 Equipment arrangement, posture, seating
 Limits comfort, angle, reachebility
 Design workplaces with rules as:
 Avoid awkward positions
 Use normal limb movement & reach limitations.
 Reduce hazards
 Minimize fatigue, control temp. & humidity
45

Ergonomics:lighting
 Illuminating instrument & workplace requires
attention
 Consider lighting intensity, angle, uniformity of
coverage
 Glare: distracting, may hide information on computer
screen, display panels
46

Ergonomics:cues
 These are indicators of functions.
 Visual indicators provide rich cues
 Lamps give active visual cues (leds on devices)
 (not use too many leds)
 Pictorial symbols describe a situation quickly & efficiently.
 Symbols for battery,fuel, temp, alarm, warning
 Shapes gives visual cues for operation(door handles,
knobs)
 Auditory cues- to signal unique & infrequent conditions
(automobile alarms, fridge alarm)
47

Packaging’s influence & its factors
 Design of instrument: affected by packaging &
enclosure
 Packaging is the mechanical structure, support &
orientation of components within electronic product.
 Shape of enclosure: power density, cooling
48

 For packaging & enclosure selection, consider
 Cost
 Size
 Shape
 Weight
 Mechanism
 Materials
 Finishes
 Appearance
 Ergonomics
 Reliability
 Regulations & standards
49

 Different markets for electronic products call for
different packaging & enclosures.
 For consumer products- cost is prime factor
 For industrial instrumentation- service support &
reliability is imp.
 Medical market-safe & rugged devices
 Military equipments- ruggedness, reliability, good
performance (cost is lower priority)
50

 Physical environment – biggest factor in selecting
package
 Physical environment includes temp, humidity,
vibration, shock, corrosion
 Industrial, medical & military products have
regulations & standards – specify operating ranges
 E.g. military electronics have to operate at ambient
temp. between -55 to +125 degree centigrade.
51

Design for manufacture, assembly
& disassembly
 Manufacturing of electronics products- accountability
of enclosures & packaging
 Manufacturing cost depends on materials, complexity,
processes, assembly & testing
 To reduce cost, do
 Simple / automated assembly
 Reduction of adjustments & caliberation
 Minimum inventory & parts handling
 Modular construction & facilitate disassembly for
maintenance
52

& disassembly
 Manufacturing of enclosures: ready made or manufacture
 Ready made enclosures: save design, tooling cost, delivered
quickly, cheaper for small/medium quantities
 Custom enclosure: fit better, cheaper for large quantities.
 Materials used for enclosure- affects price, performance
 Parameters- temp. tolerance, abrasion, chemical resistance
 Large cabinets – steel, aluminium
 Small cabinet- molded plastic
53

& disassembly
 Assembly
 Parts count – affect cost
 So reducing no. of parts will reduce assembly cost.
Maintenance & disassembly
Think on this before design
Parameters to consider while designing for disassembly:
1. Human factors
2. Reliability- how often enclosure will be opened for repair?
3. Capabilities of service men
4. Tools
5. Accessibility & maintenance frequency
54

wiring
 Wiring & cabling – interconnect signals & power
 Mechanical Failure- biggest problems
 Wiring aspect – current carrying capacity, mechanical
strength, insulation properties, shielding
 Design concerns:
Vibration, abrasion, shock
Types of connectors
EMI emission
Wire routing
Servicing
Temp., humidity, fungus.
55

Temperature
 Extremes in tem. Cause electronics failure.
 Instead of steady state high temp., large rate of change
of temp. causes reliability problem.
 Mismatched coefficients of thermal expansion during
temp. change – stress on mechanical joints & failure
 Test device for many temp. cycles
 Control temp. to minimize thermal transients &
gradients in ckts.
56

Vibration & shock
 Vibration kills electronic systems
 Frequency of Vibration failures > 4 times that of
shock failures
 Ckt boards vibrate in specific mode
 Design to reduce vibrations by
 Reducing component count
 Reducing mass at the centre of board
 Pinning the edges of ckt board
 DIP packages with longer leads are less likely to break
solder joints than leadless packges
57

Vibration & shock
58

Vibration & shock
 Use general guidelines below to reduce vibrations & also
shock:
 Clamp large components
 Use short component leads
 Add supports to long, flexible ckt boards
 Firmly anchor large components(transformers, batteries)
 Mechanically damp heavy/large structures
 Use stiff brackets
 Avoid cantilever & sliding joints
 Use special shock mounts to absorb/damp mechanical jolts
59

Safety
 Safety ground should be provided against dangerous
leakage currents & short ckts.
 For safety, voltage differentials between external
conducting surfaces should be reduced.
 Safety ground : permanent continuous low impedance
conductor with adequate capacity that runs from
power source to load.
60

Safety
61

Safety
62

Safety
63

Safety
 Ckt breakers – open for short ckts
 Leakage currents – not open ckt breaker
 So ground fault interrupters are needed
 While developing wiring for powering the user instrument,
do:
 Consider instrument & power mains as integrated system
 Always draw yr ground scheme to understand possible ckt
paths
 Do not possibly rely on building steel for a ground
conductor.
64

Noise
 Undesired electrical activity coupled from one ckt to
another
 Noise sources: (periodic/transient signal)
 Power lines
 Motors
 High voltage equipment
 Discharges & sparks (lightning, static electricity)
 High current equipment
65

Noise: block diagram
66

Noise
67

Noise: Energy coupling mechanism
 Conductive coupling: occurs at low frequencies & caused
by incorrect grounding
 Inductive coupling: Loop area of ckt determines this.
changing magnetic flux can couple ckts.
 Capacitive coupling: changing electric potentials can
drive charge thr stray capacitances.
 Electromagnetic coupling occurs at high frequencies. It
requires Tx antenna at source & Rx antenna at
susceptible receiver. Antenna must be of significant
fraction of signal wavelength to couple effectively.
68

Noise : Susceptible receiver
 Susceptibility : crosstalk on inputs, radio interference,
static discharge
 susceptibility occurs due to incorrect grounding &
improper shielding
69

Grounding
 It provides safety & signal reference.
 General principle: to minimize voltage differential
between your instrument & a reference point.
 Ground- not return path for a signal
 Safety & signal grounds – nominally conduct no
current but
 Return path – routinely conducts current
70

Grounding
 Single point grounding
 Multipoint grounding
 Single point
 It is appropriate for low current, low frequency
applications(<1 MHz)
 Ground conductor should be a short strap to reduce
high frequency noise & unsafe voltages
 E.g ADC needs single point ground for signal reference
 Separate references can generate noisy ground loops
71

Filtering
 Filtering is used to reduce noise caused due to
conductive coupling.
 A filter can either block/pass energy by 3 criteria as:
 Frequency – frequency selective filters
 Mode -common/differential
 Amplitude (surge supression)
 Common mode noise- injects current in same direction
in both signal & return lines
72

Shielding
 It prevents/supresses noise energy from coupling
between ckts.
 Types:inductive, capacitive& electromagnetic.
 Inductive: it reduces noise coupling by
reducing/rerouting magnetic flux.
 Capacitive: it reduces noise coupling by
reducing/rerouting charge in electric field.
 Electromagnetic: reduces emissions & receptions
73

Inductive Shielding
 Effective inductive shielding minimizes loop area.
 Twisting signal & return conductors in cable reduces
mutual inductance & improves shunt capacitive
balance.
 Some enclosures provide magnetic shielding by
allowing eddy currents to reflect/absorb interference
energy.
74

Capacitive shielding
 Capacitive shields shunt to ground charge that is
capacitively coupled.
 Improve capacitive shielding by reducing:
 Noise voltage & frequency
 Signal impedance
 Floating metal surfaces
75

Electromagnetic Shielding
 Emission sources: lightning, discharges, radio & TV
transmitters, high frequency ckts.
 Techniques to reduce EMI:
 Good layout & signal routing
 Reduced bandwidth
 Shielded enclosures
Openings in enclosure can leak electromagnetic radiation.
So shields must seal properly.
76

Important Questions
1. Explain the various stages in electronic product design or product life
cycle.
2. Discuss the five elements in successful human interface design of
product.
3. What is need of grounding, elaborate in detail the types of grounding.
4. Discuss noise coupling mechanisms & how to minimize these at ckt
board.
5. What is need of shielding? Explain with suitable example.
6. Write a note on: i) cognition ii) Safety iii) Grounding
7. Explain in detail Ergonomics.
8. Discuss in detail user centered design.
9. Explain DFMA approach.
10. Explain in detail: packaging & influencing factors, vibration & shock
testing.
11. How do design the wiring for the electronic product? Which are the
important factors to be considered?
77

Text Book Reference
 Kim Fowler, Electronic Instrument Design Oxford
university press.
syllabus by Dr. Anagha P. Khedkar 78

Dr. Anagha's Guide to Product Design

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