EST 200 : D ESIG N A N D

EN G IN EERIN G
MODULE 3
 SYLLABUS
Design Communication (Languages of Engineering
Design):-
Communicating Designs Graphically,
Communicating Designs Orally and in Writing.
Mathematical Modeling In Design, Prototyping and
Proofing the Design.
 ENGINEERING SKETCHES
• Drawing is very important in design because a lot of
information is created and transmitted in the drawing
process.
• D esign drawings include sketches, freehand
drawings, and
• computer-aided design and drafting (CADD)
models that extend from simple wire-frame drawings
through elaborate solid models
 ENGINEERING SKETCHES
• In brief, graphic images are used to communicate with other
designers, the client, and the manufacturing organization. Sketches and
drawings:
• serve as a launching pad for a brand-new design;
• support the analysis of a design as it evolves;
• simulate the behavior or performance of a design;
• record the shape or geometry of a design;
• communicate design ideas among designers;
• ensure that a design is complete (as a drawing and its associated
marginalia may remind us of still-undone parts of that design);
• communicate the final design to the manufacturing specialists.
 SKETCHING
• Sketching is a powerful tool in design because it enables us to
convey our design ideas to others quickly and concisely.
• Types
A.Orthographic sketches
• lay out the front, right and top views of a part
B. Axonometric sketches
• start with an axis, typically a vertical line with two lines 30
drgree from the horizontal.
C.Oblique sketches
• The front view is blocked in roughly first, depth lines are then
added, and details such as rounded edges are added last.
D. Perspective sketches
THE SEVERAL FORMS OF
ENGINEERING DRAWINGS
• When we communicate design results to a manufacturer,
we must think very carefully about the fabrication
specifications that we are creating in drawings, as well
as those we write.
• we must ensure that our drawings are both appropriate
to our design and prepared in accordance with
relevant engineering practices and standards.
 DESIGN DRAWINGS
• Layout drawings
• working drawings that show
the major parts or
components of a device and
their relationship
• They are usually drawn to
scale, do not show
tolerances, and are subject
to change as the design
process evolves.
 DESIGN DRAWINGS
• Detail drawings
• show the individual parts or components of
a device and their relationship
• These drawings must show tolerances, and
they must also specify materials and any
special processing requirements.
• D etail drawings are drawn in conformance
with existing standards, and are changed
only when a formal change order provides
authorization.
 ASSEMBLY DRAWINGS
• Assembly drawings
• show how the individual
parts or components of
a device fit together. An
exploded view is
commonly used to
show such “fit”
relationships
 DETAIL D R AW I N G S
• These drawings are used to communicate the details of our design to
the manufacturer or machinist.
• They must contain as much information as possible while being both as clear
and as uncluttered as possible.
• There are certain essential components that every drawing must have to
ensure that it is interpreted as it is intended
• standard drawing views;
• standard symbols to indicate particular items;
• clear lettering;
• clear, steady lines;
• appropriate notes, including specifications of materials;
• a title on the drawing;
• the designer’s initials and the date it was drawn;
• dimensions and units; and
• permissible variations, or tolerances.
 C A D - MODELS
• Good for digital visualization
• The making of 3D models in
computers software is called
geometric modelling
• Lots of C AD software are available
depending on the application
• These software provide many features
such as color rendering shading texting
etc. to communicate the design more
close to the reality
• The modelled part can be rotated,
sectioned and zoomed so that any
Complex shape can be
communicated to the another person
without confusion
 DETAIL DRAWINGS
Figure : A detail drawing of the
handle of a screwdriver. This drawing
uses a set of symbols and the
particular placement of these
symbols conveys information about
the size and location of certain
features of the screwdriver handle.
In addition, the drawing contains
information about the materials to
be used, the finish of the part, the
person who created it, and the
date it was created. Drawing
courtesy of R.Erik Spjut.
 C O M M U N I C AT I N G DESIGNS ORALLY
A N D IN WRI TI NG
•REPORTING is an essential part of a design project

•We communicate final design results in several ways, including

oral presentations, final reports (that may include design
drawings and/or fabrication specifications), and prototypes
and models

•The primary purpose of such communication is to inform our

client about the design, including explanations of how and
why this design was chosen over competing design
alternatives
 C O M M U N I C AT I N G DESIGNS ORALLY
A N D IN WRI TI NG
•It is most important that we convey the results of the design
process

•we should ensure that final reports and presentations are not
narratives or chronologies of our work

•Rather, the presentations and reports should be lucid

descriptions of design outcomes, as well as the processes with
which those outcomes were achieved
GUIDELINES FOR TECHNICAL
COMMUNIC ATION
1. Know your purpose
2. Know your audience
3. Choose and organize the content around yourpurpose
and your audience
4. Write precisely and clearly
5. Design your pages well
6. Think visually
7. Write ethically!
 GUIDELINES FOR TE C H NI C AL
C O M M U N I C AT I O N
1.Know your purpose
• This is the writing analog of understanding objectives and
functions for a designed artifact

• Just as we want to understand what the designed object

must be and must do, we need to understand the goals
of a report or presentation.
 GUIDELINES FOR TE C H NI C AL
C O M M U N I C AT I O N
1.Know your purpose
• design documentation seeks to inform the client about
the features of a selected design
• design team may be trying to persuade a client that a
design is the best alternative
• a designer may wish to report how a design operates to
users, whether beginners or highly experienced ones
GUIDELINES FOR TECHNICAL
COMMUNIC ATION
2.Know your audience
• When documenting a design, it is essential that a design
team structure its materials to its targeted audience
• Taking time to understand the target audience will help
ensure that its members appreciate your
documentation
GUIDELINES FOR TE C H NI C AL
C O M M U N I C AT I O N
3. Choose and organize the content around your purpose
and your audience
• The key element is to structure the presentation to best
reach the audience
• There are many different ways to organize information
• going from general concepts to specific details
(analogous to deduction in logic),
• going from specific details to general concepts
(analogous to induction or inference),
• describing devices or systems.
GUIDELINES FOR TE C H NI C AL
C O M M U N I C AT I O N

3. Choose and organize the content around your purpose

and your audience
• Once an organizational pattern is chosen, no matter which
form is used, the design team should translate it into a
written outline.This allows the team to develop a unified,
coherent document or presentation while avoiding
needless repetition
GUIDELINES FOR TE C H NI C AL
C O M M U N I C AT I O N

4. Write precisely and clearly

• Some specific elements that seem to occur in all good
writing and presentations
• These include effective use of short paragraphs that have
a single common thesis or topic
• Direct sentences that contain a subject and a verb;
and active voice and action verbs that allow a reader
to understand directly what is being said or done
GUIDELINES FOR TE C H NI C AL
C O M M U N I C AT I O N

4. Write precisely and clearly

• Opinions or viewpoints should be clearly identified as such

• As long as the designer remembers that the goals of

both technical and nontechnical communications
remain the same
GUIDELINES FOR TE C H NI C AL
C O M M U N I C AT I O N
5. Design your pages well
• A long section divided into several subsections helps
readers to understand where the long section is going,
and it sustains their interest over the journey

• Tables should be treated as a single figure and should

not be split over a page break

• Simple and direct slides encourage readers to listen to

the speaker without being distracted visually
GUIDELINES FOR TE C H NI C AL
C O M M U N I C AT I O N
5. Design your pages well
•Thus, text on a slide should present succinct concepts
that the presenter can amplify and describe in more
detail. A slide does not have to show every relevant
thought

•It is a mistake to fill slides with so many words (or other

content) that audiences have to choose between
reading the slide and listening to the speaker, because
then the presenter’s message will almost certainly be
diluted or lost
GUIDELINES FOR TE C H NI C AL
C O M M U N I C AT I O N
6.Think visually
• Just as designers often find that visual approaches are
helpful to them, audiences are helped by judicious use of
visual representation of information

• Given the enormous capabilities of word processing and

presentation graphics software, there is no excuse for a
team not to use visual aids in its reports and presentations
GUIDELINES FOR TE C H NI C AL
C O M M U N I C AT I O N
6.Think visually
• A team should not allow their graphics’ capabilities to
seduce them into clouding their slides with artistic
backgrounds that make the words illegible

• As it is with words, is to know your purpose and your

audience, and to use your medium appropriately
GUIDELINES FOR TE C H NI C AL
C O M M U N I C AT I O N
7. Write ethically!
• All results or test outcomes, even those that are not
favorable, are presented and discussed

• Ethical presentations also describe honestly and directly

any limitations of a design

• It is also important to give full credit to others, such as

authors or previous researchers, where it is due
 ORAL PRESENTATIONS
• TELLING A CROW D WHAT’S BEEN DONE
• Most design projects call for a number of both formal
and informal presentations to clients, users, and
technical reviewers

• Because of the variety of presentations and briefings

that a team may be called upon to make, it is
impossible to examine each of them in detail.
 ORAL PRESENTATIONS
• TELLING A CROW DWHAT’S BEEN DONE
• However, there are key elements common to most of
them.
• Foremost among these needs to
1. Identify the audience
2.Outline the presentation
3. Develop appropriate supporting materials
4. Practice the presentation
 K N OW I N G THE AUDIENCE

• Who’s Listening?
• a team planning a briefing should consider factors
such as varying levels of interest, understanding,
and technical skill, as well as the available time

• Once the audience has been identified, a team can

tailor its presentation to that audience
 K N OW I N G THE AUDIENCE

• As with other deliverables, the presentation must be

properly organized and structured:
• The first step is to articulate a rough outline
• The second is to formulate a detailed outline
• The third is to prepare the proper supporting materials
such as visual aids or physical models
 THE PRESENTATION: OUTLINE
•A title slide : that identifies the client(s), the project, and the
design team or organization responsible for the work
being presented.This slide should include company logos

•A roadmap : for the presentation that shows the

audience the direction that the presentation will take. This
can take the form of an outline, a flowchart, a big picture
slide, and so on

•A problem statement: which includes highlights of the

revised problem statement that the team produced after
research and consultation with the client
 THE PRESENTATION: OUTLINE
•Background material on the problem: including relevant
prior work and other materials developed through team
research. References should be included but may be
placed in a slide at the end of the presentation

•The key objectives of the client and users : as reflected in

the top level or two of the objectives tree

•The key constraints that the design must meet

•Functions that the design must perform : focusing on basic

functions, and means for achieving those functions.
 THE PRESENTATION: OUTLINE
•Design alternatives : particularly those that were considered
at the evaluation stage, including diagrams and descriptions
of each

•Highlights of the evaluation procedure and outcomes:

including key metrics or objectives that bear heavily on the
outcome

•The selected design : explaining why this design was chosen

•Features of the design : highlighting aspects that make it

superior to other alternatives and any novel or unique
features.
 THE PRESENTATION: OUTLINE

•Proof-of-concept testing : especially for an audience of

technical professionals for whom this is likely to be of great
interest

•A demonstration of the prototype : assuming that a

prototype was developed and that it can be shown.Video
or still photos may also be appropriate here

•Conclusion(s): including the identification of any future

work that remains to be done, or suggested improvements
to the design
 PRESENTATIONS ARE VISUAL EVENTS
•At the earliest stages of the presentation planning, the
design team should find out what devices (e.g., overhead
projectors, computer connections, projectors, and
whiteboards) are available and the general setting of the
room in which it will be presenting

•Tips & pointers

•Limit the number of slides

•Be sure to introduce yourself and your teammates on

the title slide
 PRESENTATIONS ARE VISUAL EVENTS
• Tips & pointers
• Beware of “clutter”. Slides should be used to highlight
key points; they are not a direct substitute for the
reasoning of the final report
• Make points clearly, directly, and simply
• Use color skillfully
• Use animation appropriately
• Do not reproduce completed design tools
• Consider carefully the size and distance of the
audience
 PRACTICE MAKES PERFECT
•To be effective, speakers typically need to practice their
parts in a presentation alone, then in front of others,
including before an audience with at least some people
who are not familiar with the topic

•we want to speak to an audience in their language, and

that we want to maintain a professional tone

•Practice sessions, whether solitary or with others, should be

timed and done under conditions that come as close as
possible to the actual environment
 PRACTICE MAKES PERFECT
• While practicing its presentation, a team ought to prepare
for questions from its audience by:
• Generating a list of questions that might arise, and their
answers;
• Preparing supporting materials for points that are likely to
arise (e.g., backup slides that may include computer
results, statistical charts, and other data that may be
needed to answer anticipated questions)
• Preparing to say “I don’t know", or “We didn’t consider
that". This is very important: A team, that is, to be caught
pretending to know has undermined its credibility and
invited severe embarrassment.
MATHEMATICAL MODELING
IN DESIGN
• MATHEMATICAL MODELS are central to design
because we have to be able to predict the
behavior of the devices or systems that we are
designing.
• It is important for us to ask: How do we create
mathematical models? How do we validate such
models? How do we use them? And, are there any
limits on their use?
SOME MA T HE MA T I CA L HABITS OF T H O U G H T
FOR D E S I G N M O D E L I N G

•We will focus on representing the behavior and function

of real devices in mathematical terms.
•Basic Principles of Mathematical Modeling
•Why do we need a model?
•For what will we use the model?
•What do we want to find with this model?
•W hat data are we given?
•What can we assume?
 SOME MA T HE MA T I CA L HABITS OF T H O U G H T
FOR D E S I G N M O D E L I N G

•How should we develop this model, that is, what are the
appropriate physical principles we need to apply?
•What will our model predict?
•Can we verify the model’s predictions (i.e., are our
calculations correct?)
•Are the predictions valid (i.e., do our predictions conform to
what we observe?)
•Can we improve the model?
 A BSTRAC TIO N S, SC A LIN G , A N D LU M PED
ELEMENTS
• Abstractions: An important decision in modeling is choosing the right level
of detail for the problem, which thus dictates the level of detail for the
model.
• Stated differently, thinking about finding the right level of abstraction or
detail means identifying the right scale for our model means thinking
about the magnitude or size of quantities measured with respect to a
standard that has the same physical dimensions.
• we often say that a “real", three-dimensional object behaves like a simple
spring.When we say this, we are introducing the idea of a lumped
element model in which the actual physical properties of a real object
or device are aggregated or lumped into less detailed, more abstract
expressions.
SOME MATHEMATIC AL TOOLS FOR DESIGN
MODELING
• Dimensions and Units
• Every independent term in every equation we use has to be
dimensionally homogeneous or dimensionally consistent, that is, every
term has to have the same net physical dimensions.
• The physical quantities used to model objects or systems represent
concepts, such as time, length, and mass, to which we attach numerical
measurements or values.
• Fundamental or primary quantities can be measured on a scale that is
independent of those chosen for any other fundamental quantities. For
example, mass, length, and time are usually taken as the
fundamental mechanical dimensions or variables.
• Derived quantities generally follow from definitions or physical laws, eg :
force is a derived quantity that is defined by Newton’s law of motion.
 DIMENSIONS A N D UNITS
• If mass, length, and time are chosen as primary quantities,
then the dimensions of force are (mass x length)/(time)2.
We use the notation of brackets [ ] to read as “the
dimensions of ". If M, L, and T stand for mass, length, and
time, respectively, then

• Similarly, [A=area]=(L)2 and [ρ = density] = M/(L)3.

• The units of a quantity are the numerical aspects of a
quantity’s dimensions expressed in terms of a given
physical standard
SOME MATHEMATIC ALTOOLS FOR DE SIGN
MODELING
• Significant Figures
• In scientific notation, the number of significant figures is equal to the
number of digits counted from the first nonzero digit on the left to
either
• (a) The last nonzero digit on the right if there is
no decimal point, or
• (b) The last digit (zero or nonzero) on the right when there is a
decimal point.
• we should always remember that the results of any calculation or
measurement cannot be any more accurate than the least
accurate starting value.
• any calculation is only as accurate as the least accurate value we
started with
SOME MATHEMATIC AL TOOLS FOR DESIGN
MODELING
SOME MATHEMATIC AL TOOLS FOR
DESIGN M O D E L I N G

• Dimensional Analysis
• We can learn a lot about some behavior by doing dimensional
analysis, that is, by expressing that behavior in a dimensionally
correct equation among certain variables or dimensional groups.
• The basic method of dimensional analysis is an informal unstructured
approach for determining dimensional groupings that depends on
constructing a functional equation that contains all of the relevant
variables, for which we know the dimensions
• We then identify the proper dimensionless groups by thoughtfully
eliminating dimensions.
SOME MATHEMATIC ALTOOLS FOR DESIGN
MODELING
• Physical Idealizations, Mathematical Approximations,
and Linearity
• First, we identify those elements that we believe are
important to the problem.
• Second, we translate our physical idealization into a
mathematical model
• Third, try to build models that are, mathematically
speaking, linear models. Linearity shows up in other
contexts. Consider geometrically similar objects, that is,
objects whose basic geometry is essentially the same.
 CONSERVATION A N D B ALANCE LAWS
• Many of the mathematical models used in engineering
design are statements that some property of an object
or system is being conserved.
• Such balance or conservation principles are applied to
assess the effect of maintaining levels of physical attributes.
• Conservation and balance equations are related:
Conservation laws are special cases of balance laws.
 PROTOTYPING A N D
P R O O F I N G THE DESIG N

•Focus on how to translate our design ideas into models

and prototypes that can be used to test our design
concepts and communicate our ideas to the client.
•Often the first step in such a process involves sketching or
drawing our design, we can use these representations to
create the prototype or model

•3D representation
•as an input to a computational modeling program to
simulate the design’s performance under specified
conditions;
 PROTOTYPING A N D
P R O O F I N G THE DESIG N

• 3D representation
• as an input into a variety of rapid prototyping
technologies, such as 3D printing;
• to generate detailed engineering drawings of the design;
• to guide the tool path in computer numerical-controlled
(CNC) machining
 PROTOTYPES
• “original models on which something is patterned.” They are
also defined as the “first full-scale and usually functional forms
of a new type or design of a construction
• prototypes are working models of designed artifacts.
• They are tested in the same operating environments in which
they’re expected to function as final products.
 MO DE L
• “a miniature representation of something,” or a “pattern of
something to be made,” or “an example for imitation or
emulation.”
• We use models to represent some devices or processes.
• They may be paper models or computer models or physical
models.
 MO DE L
• We use them to illustrate certain behaviors or phenomena as
we try to verify the validity of an underlying (predictive)
theory.
• Models are usually smaller and made of different materials
than are the original artifacts they represent, and they are
typically tested in a laboratory or in some other controlled
environment to validate their expected behavior.
 PROOF OF C O N C E P T

• refers to a model of some part of a design that is used

specifically to test whether a particular concept will
actually work as proposed
• Doing proof-of-concept tests means doing controlled
experiments to prove or disprove a concept
 W H E N D O WE BUILD A PROTOTYPE?
• “It depends.”
• the size and type of the design space,
• the costs of building a prototype,
• the ease of building that prototype,
• the role that a full-size prototype might play in ensuring the
widespread acceptance of a new design,
 W H E N D O WE BUILD A PROTOTYPE?
• the number of copies of the final artifact that are expected
to be made or built.
• There is no obvious correlation between the size and cost of
prototyping—or the decision to build a prototype—and the
size and type of the design space.
• it is that the project schedule and budget should reflect
plans for building them.
 BUILDING MODELS A N D PROTOTYPES

• The important questions we must ask are:

• What do we want to learn from the model or prototype?
• Who is going to make it?
• W hat parts or components can be bought?
• How, and from what, is it going to be made?
• How much will it cost?
 BUILDING MODELS A N D PROTOTYPES
•There are many options for constructing
prototypes and models
•Mock-ups: One option for making basic
models or prototypes is to construct a
mockup of a 3D part from 2D cutouts.
These 2D parts can be made using a vinyl
cutter or a laser cutter, and parts are then
assembled into 3D mock-ups of a design.
Materials used for these mock-ups might
be foam, thin plastic, or wood.
 BUILDING MODELS A N D PROTOTYPES
•Machining: We may have the option of machining parts
or all of our prototypes ourselves in a machine shop.
 BUILDING MODELS A N D PROTOTYPES

• Rapid prototyping technologies: Rapid prototyping

technologies have emerged in recent years as relatively
fast and cheap ways to fabricate prototypes that would
otherwise need to be injection molded. Rapid prototyping
techniques use 3D CAD models as inputs, and convert
these 3D files into thin 2D layers to build the 3D part. Rapid
prototyping technologies include stereo-lithography and
selective laser sintering, which involve using a laser to
harden either a resin bath or a polymer powder in a
particular configuration to build each layer.
 REFERENCES

• “ENGINEERING DESIGN: A PROJECT-BASED INTRODUCTION,” By

CLIVE L. DYM, PATRICK LITTLE, and ELIZABETH J.ORWIN, fourth edition,
wiley
• DESIGN & ENGINEERING : Basics of product development By Dr.
SADIQ A