Whatever area you will

choose…

This course is fundamental.

A bit of history
• The objective need to communicate
A bit of history
• The time line
History in images
Artistic Drawing

“Paper could take about

anything”

Observe the way

the posts are crossing

Have you ever seen

such a construction?
The fundamental difference ?

Artistic Drawing Mechanical/Technical drawing

Content of the Course
Introduction to graphic language and design — means and
techniques. The third and the first angle projections.
Orthographic projection of points, lines, planes and solids.
Principal and auxiliary views. Views in a given direction.

Sectional views. Intersection of lines, planes and solids.

Development of surfaces. Drafting practices. Dimensioning,
fits and tolerancing. Computer-aided drawing and solid
modelling. Working drawings — detail and assembly
drawing. Design practice. Machine elements representation.
Case Study
 Content of the Course A, B, C, D ARE POINTS

B C
 Content of the Course A, B, C, D ARE POINTS

AB, BC, CD, DA, CA ARE LINES

A

B C
 Content of the Course A, B, C, D ARE POINTS

AB, BC, CD, DA, CA ARE LINES

A
ABC, CDA ARE PLANES

B C
 Content of the Course A, B, C, D ARE POINTS

AB, BC, CD, DA, CA ARE LINES

A
ABC, CDA ARE PLANES

ABCD IS A SOLID

B C
Content of the Course A, B, C, D ARE POINTS

AB, BC, CD, DA, CA ARE LINES

A
ABC, CDA ARE PLANES
CASE
STUDY ABCD IS A SOLID

T OP
EN EL
M EV
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INTERSECTION

C L
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O
TI
O AL

L
A
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PR AR

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N
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C
PERSPECTIVE ISOMETRIC

TE
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COMMUNI EXPLAIN R
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B C
Mechanical components
Geometry
is a fundamental thing!

In Nature

In Human Need

• http://www.webshots.com/g/55.html
Introduction
to Graphic Language and Design
• Why graphics is necessary?
– Communicate information that would not be possible to exchange
in writing

• Why not use pictures to communicate visual information?

– Usually, a drawing represents something that exists just at
conceptual level

• Why not use pictorial representation?

– The information contained in a drawing must be used to build an
accurate component/system.
What is Drawing?
• Drawing is a graphic representation of a real
thing, an idea, or a proposed design

• Why graphic representation?

• Graphic method of representation is a basic
natural form of communication of ideas that is
universal and timeless.

• It is impossible to explain things through text.

 Graphic Language
A simple component!

• How hard to
define in words?

• Try to describe in words the

following representation: A
MECHANISM
Graphic Language
• Graphics language is universal
Graphic Language

• The information can be conveyed regardless the

spoken language

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2. ÐŷƁţāŖĉ 5. Z´¶ $æÊ¿£ŠŠŠ 8. š^?%ëŢŪųĺ З— 11. ※—‘…€
3. ®@µ¶œƒ/ 6. €¶¸¹ì±®wd]Ê !;8 9. €ßu $*” éÐÐ
Graphic Language
• When spoken language is known, the information is more
accurate
Essentials of a good drawing
• Should represent the concept/idea/geometry
clearly

• Should be able to communicate with others with

out doubt

• Should respect the manufacturing feasibility

• Should favor a lot standardization

Let’s see how to make a good mechanical drawing!

Views
• An object could be represented in more ways:
 Projections/ Drawing Basics
• The way one is visualizing an object
(Simple and sufficient)
• Two basic projection types – use parallel
projection

Perspective Parallel
Projections and views (brief)
What is perspective representation
• Representation of objects based on the rule of distance: 2
identical object are seen different from different distances
– shape is deformed too
• This type of representation is not used for technical
purposes in Mechanical Engineering
What should be drawn?
• What is seen – follow certain rules
Views - Multi-view representation
Project the visible and hidden
edges/corners
Views - Multi-view representation
Multi-views
• A part is represented in multiple views (a single part is
seen as more than one part)

• The representation makes the user to fully understand

the shape of the part, to perceive the relative proportions
of the geometric features and to position the features one
with respect to another

• The parallel projection principle and the alignment of the

features is used in the representation
Type of Projections
Projection planes
• The component is aligned with
respect to the principal projection
planes
– Top (T) or Horizontal (H)
– Front (F) or Vertical (V)
– Side (S) or Profile (P)

• The projection is carried such that

each feature parallel to the
projection planes to be seen as true
length
Object orientation
Projection principles
Projection principles
Projection Types

Third angle projection First angle projection

Relative position of the views
• All views must be aligned with respect to
each other – feature to feature
Drafting strategies (3 view)
Technical procedures
• When representing the third view, scale, divider of
miter line is used to ensure the alignment of the
three views
Example

• Represent the shown component using multiple

view representation
 Example
• Start with the front view
• The edge C cannot be seen but is
represented by a dashed line (hidden
feature)

C
Example
• Align the top view with respect to the
front view

C
 Example
• Complete the representation
• Later, dimensioning and comments will
be added to the drawing
The principal projection planes

• The object should

be aligned with
respect to the
projection planes
The principal projection planes
- unfolded
• Notice the relationship
between the features

• The depth – distance

from the front to the
object is measured in
the Horizontal and
Profile
Multi-view Projection Drawing
How to generate
• Assume the given part as

shown besides.

• Position the part in a

convenient way, to simplify

the representation as much

as possible
Multi-view Projection Drawing
How to generate • Select the position of the

projection planes

• Start with one of the

projections – usually the front

view

• Each edge is represented

based on the principle of the

parallel projection
Multi-view Projection Drawing
How to generate • Complete the first view.
• Use the basic representation
Principles:
• visible edge is seen as a full
line
• non-visible feature is
represented by a dash-line
• axes of symmetric features
are represented by dash-dot
lines
Multi-view Projection Drawing
How to generate • Continue with the second view
• Make sure that you have
accurately align the two views.
• Use the same rules for
representation.
• The alignment lines must be
perpendicular to the edge of
the projection planes
• (The lines of sight are always
perpendicular to the fold line).
Multi-view Projection Drawing
How to generate • Continue with the third view
• Make sure that you have
accurately align all views.
• Use the same rules for
representation.
• The alignment lines must be
perpendicular to the edges of
the projection planes
• (The lines of sight are always
perpendicular to the
corresponding fold lines).
Multi-view Projection Drawing
How to generate

• Complete the representation

• Separate the top from the
profile view along the edge
(fold line)
• Unfold the three views to lay
them on the same plane
Multi-view Projection Drawing
How to generate

• This is the 3-view

orthographic representation
of the selected part
(FLANGE)

• * Do not erase any of the

lines when writing a test
Orthographic multi-view

• The above part will be projected on all 6

projection planes
Orthographic multi-view
Orthographic multi-view
Orthographic multi-view
Orthographic multi-view
Orthographic multi-view

Solid models
Minimum number of views
• Certain shapes could be described in less number of
views
• One must use the minimum number of views for
representation
Minimum number of views
• Do not produce more views than necessary
Centerline
• Axi-symmetric features are indicated with a
dash-point line - CENTERLINE
Hints on understanding shapes
• Try to “see” the way a solid is created out
of primitives
Hints on understanding shapes
• Complex shapes could be generated using Boolean
operations
Pay attention to edges
Projections and views (brief)
Where drawing is used?
• It is important to know the rationale of
drawing
• Drawing is an international communication
language
• Fast way to convey certain type of
information
• Limited number of concepts are better
represented by drawing, but not all
The design process
• Drawings are created to represent parts
that do not exist yet
• The designed parts are intended to be
manufactured
• The drawings must carry all the necessary
information that enables the fabrication of
the part
The design process
• Design involves constrained creation
• Constraints:
• Technology limits
• Human and environment concerns
• Durability and reliability
• Cost
• Market requirements
• Etc.
The design process
• REPRESENTATION
• PERCEPTION
Basic requirements to be able to
• KNOWLEDGE perform a design
• INTUITION All the above interacts in your
• CONCEPT judgment even if you are not
aware of it
• PURE CONCEPT
• You have to train your judgment
EMPIRICAL CONCEPT
to be able to perform solution-
• NOTION solving based thinking
• IDEA The graphic helps you to do so
The design process
• A design is created after analysis, full
understanding of requirements and
constraints and synthesis
• Two individuals may not come with the
same solution to the same problem
• Example: Connect two straight pipes ND 4” to avoid
leaking of the gas and to permit easy maintenance
of the segment
Solutions to the problem
• Multiple: flanges, clips, clamps, seals, etc.
1. Problem Defn.
2. Concept and
ideas
The design process
3. Solutions
4. Models/Prototype
5. Production and
working drawings

Concurrent engineering
approach
The design process
The design process
Drawings in product
development

Designer

Functional
Drawings Sketches

drawings
Prod.
Vendors/
Mechanical
Customers
Engineer
Production
Shops
Assembly Assembly
Drawings Drawings

Quality
Assurance Assembly
Drawings in product
development
A Component !