Technical Drawing with Engineering Graphics and Design in Practice_Definitions, Importance, and Applications

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Technical Drawing with Engineering
Graphics & Design in Practice:
Definitions, Importance, and
Applications
SEPTEMBER 2019
Definition of Engineering Graphics; Definition
of Graphical Engineering; What Engineering
Graphics and Design is all About; Basic
Components of Engineering Graphics—the Code
of Practice; Importance of Engineering
Graphics and Design; Uses/Applications of
Engineering Graphics and Design
EDITED
BY IHAGH GODWIN

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Motivation & Environment Presents
Technical Drawing with Engineering
Graphics & Design in Practice:
Definitions, Importance, and
Applications
Content: Definition of Engineering
Graphics; Definition of Graphical
Engineering; What Engineering Graphics
and Design is all About; Basic Components
of Engineering Graphics—the Code of
Practice; Importance of Engineering
Graphics and Design; Uses/Applications of
Engineering Graphics and Design

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2019 Edition
Motivation & Environment
Copyright Free 2019
You may distribute without permission,
and share with anybody
Edited by Ihagh G.
MSc (Water Resources & Environmental Eng.);
BSc (Civil Engineering), and 7 years of
university teaching experience
Editor, Motivation & Environment
Website: https://motenv.wordpress.com/
Email: godwinihagh@gmail.com

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Table of Contents Page
Table of Contents……………………………………………………… 4
1.0 Introduction……………………………………………………… 5
2.0 Definition of Engineering Graphics……………………….. 7
3.0 Definition of Graphical Engineering…..………………….. 7
4.0 What Engineering Graphics & Design is all About……. 8
 What is Engineering Design?.......................................8
 Application of Technical Drawing with Engineering
Graphics in Engineering Design…………………………..... 11
5.0 Basic Components of Engineering Graphics—the Code of
Practice……………………………………………………………………. 13
6.0 Importance of Engineering Graphics & Design………... 16
7.0 Uses/Applications of Engineering Graphics & Design… 17
Interested in starting and building a website?……………......20

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1.0 Introduction
In the technologically advanced world of today, technical drawing
with engineering graphics and design employs every important
cognitive and manipulative skill to aid engineering graphical
communication which uses lines, dimensions, scales, symbols,
and signs to illustrate how products, processes, services, and
systems look and work.
Technical drawing is applied in many fields, one of which is
engineering graphics and design. Many students usually study
technical drawing before gaining admission to read engineering
and study engineering graphics which is just one out of many
engineering subjects. The transition from technical drawing to
engineering graphics and further study is usually much easier for
students who have past experience in technical drawing.
Although many people assume that technical drawing is the
same as engineering graphics, there is actually a difference
between the two: technical drawing is generally employed in
producing diagrams and representations of object and shapes on
paper, while engineering graphics is a technique used by
engineers to produce engineering design drawings, including

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pictorial representations of data in computer-aided design (CAD)
and manufacture with the use of softwares.
Engineering graphics is somewhat an advanced type of technical
drawing that clearly expresses the practical requirements for
engineering forms or structures. Technical drawing goes hand in
hand with engineering drafting graphics and design. Generally,
whenever pencil and paper, or computer is used for drafting, it
must be ensured that drafts are clear and visible enough to
demonstrate how things work/would work.
The procedure, skill, or actions often used to produce engineering
graphics can be regarded as technical drawing or drafting. Note
that technical drawing is also be applied in disciplines that are
not usually regarded as fields of engineering; examples include
landscaping, architecture, environmental health science, cabinet
making, garment-making, etc.
Engineering graphics often combines many colors, various texts,
and illustrations to communicate clearly and effectively using
drawings, especially with people who understand the language of
technical, or engineering drawing.

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2.0 Definition of Engineering Graphics
Engineering graphics can be defined as a graphical language that
gives precise pictorial expressions of engineering structures and
is used to make communication possible between designers and
other people who might not necessarily be engineering
professionals. Engineering graphics, which usually provides
details that cannot be derived from engineering calculations,
helps to convey ideas to people, and convert concepts into reality
if drafts, illustrations or drawings follow universally accepted
codes, criteria, and conventions.
3.0 Definition of Graphical Engineering
Graphical engineering can be defined as the branch of
engineering that deals with the study of computer-aided design
(CAD) and imaging software aimed at creating digital sketches of
engineering models, structures, plans, and projections for
beneficial purposes.
Furthermore, graphical engineering combines the knowledge of
technical drawing with engineering graphics, and computer
software and hardware to illustrate and manipulate engineering

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data/content for practical purposes. It is quite common for
graphical engineering students to study programming language
and 3-D maths, and use programming interfaces (API) to build 3-
D engines, and rendering systems for 2-D and 3-D visuals.
4.0 What Engineering Graphics and Design
is all About
Engineering graphics and design is a combined creative activity
aimed at producing engineering structures or outcomes that are
useful to people and society. The graphic description of any
engineering structure has to be clear and presentable, and in
such a form that can be easily understood and constructed or
built without much assistance from the designer.
What is Engineering Design?
Engineering design is the type of design practiced by engineers.
Engineering design is different from planning because in
planning—unlike in engineering design—expressions or
presentations are not sufficiently complete or detailed enough to
be built like final and complete designs can.

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Application of scientific principles is the major thing that
distinguishes engineering design from the type of design
practiced by other professions: the major difference between
engineering graphics and design, and the type of design practiced
by other disciplines/professions is that, before construction,
engineers use the principles of science to prove or demonstrate to
an appreciable extent whether designs will work.
With a great degree of accuracy, scientific principles can be used
to predict the behavior of physical systems—this is where
engineering design comes in. When applying engineering design,
planned systems do not have to be real; however, they may have
to be clearly and precisely described in mathematical terms.
In many fields of engineering, one of the most important goals of
design is to ensure that all structures (bridges, buildings,
automobiles, and aircraft) are capable of carrying loads and
forces without failing or collapsing.
In order to determine whether a given bridge or building can
withstand forces without failing, existing mathematical models
have to be employed in making checks and assessments—this is
design. Loads are expressed in mathematical terms, and relevant

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scientific principles (such as Newton’s laws and Hooke’s law) are
used to estimate the stresses that would likely be produced in a
structure whenever it is acted upon by various weights of loads
or forces which could include human beings, chairs, tables, wind,
etc.
By comparing the estimated stresses with the limiting values of
the strengths of materials expected to be used, it can be
determined whether or not any structure can perform certain
functions. Engineering design is usually combined with
engineering graphics, and used to make important and precise
descriptions for geometric and material properties of structures.
Without employing the principles of science, another way to
determine whether a structure under design can perform its
intended function is to build it, test it, and expect the best result.
But in most cases, this is not a recommendable option because it
doesn’t follow any tested and trusted guidelines like the fields of
engineering do. Generally, the principles of science have an upper
hand when it comes to design because they are based on past
research and proven theories.

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Before introducing technical drawing with engineering graphics
into the scheme of planned construction, engineering designs
have to be carefully validated (proven that they are in accord with
important and applicable design criteria) to ensure that the most
important concerns have been addressed, and intended
structures will perform their functions after being built or
constructed in accordance with their design.
Application of Technical Drawing with Engineering Graphics
in Engineering Design
Technical drawing with engineering graphics has two major roles
in practical engineering design processes:
 To help communicate or pass on information easily and
understandably between participants of engineering design
processes.
 To help designers create better ideas when validating design
outcomes or decisions.
It is important to note that in engineering practice, all
graphics/drawings remain just a means to an end—successful
construction and operation of structures. Generally, engineering
graphics are created to serve and support design processes,

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which in turn assist in the construction of structures that serve
greater purposes in society.
It is in this regard that engineering graphics is significantly
diﬀerent from artistic drawings that are created by artists. Unlike
engineering drawing, the intention of most artistic drawings to
create visually or aesthetically appealing effects.
In many cases, engineering designers do not build or construct
their designs or works; for example, many engineering works are
usually constructed or built by contractors who work
independently of designers.
This implies that there is a need to communicate effectively via
drawings that can clearly and suitably describe what has been
designed to be constructed or built. Because engineering works
are usually large and spacious, many objects are scaled down
and graphically communicated in two- and three-dimensions
respectively—i.e., in 2-D & 3-D.
Most times, the complete and final graphics of objects are issued
at the end of engineering design processes and provide complete
descriptions of objects that would be constructed or built.

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Engineering graphics can also be used to communicate internally
within an organization that designs structures; for instance,
communication can be from one designer to another, or from a
designer to drafting staﬀ.
Note
In order to effectively apply technical drawing with engineering
graphics in any design process, engineers or students should be
able to produce various types of drawing, formally, and
informally. Generally, all drawings help the imagination to create
and develop new ideas.
5.0 Basic Components of Engineering
Graphics—the Code of Practice
Basic technical drawing is an essential component of all types of
engineering graphics, nationally, and internationally. Within
national and international trade, goods that are technical almost
always need to be accompanied by service diagrams or technical
illustrations that express shapes, dimensions, and how
components work whenever projections are assembled.

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Examples of services could include consultancy work, design of
communication towers, installation procedures for technological
inventions, or even instructions on how to assemble simple
devices.
Whenever information is exchanged, especially between people
who don’t understand/use a common verbal language, technical
drawings can give clarity, even when language barriers exist.
Before a unified approach was ever agreed on, IS:696: “Code of
practice for general engineering drawing” was originally issued in
1955, and revised twice in 1960 and 1972 respectively.
Growing international cooperation and exportation of technology
has necessitated the development of an internationally unified
format that consists of components, rules, codes, conventions,
and symbols that illustrate the language of technical drawing
with engineering graphics.
Since the publication of the code of practice, many countries
have made a lot of progress in standardizing the components of
technical drawing with engineering graphics because they
adhered to the mutual agreement on the use of codes in, as
established between countries.

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The basic components of the code of practice used in technical
drawing with engineering graphics include:
 List of drawing tools and items.
 Sizes/layout of drawing sheets.
 Folding of drawing sheets: how to fold drawing sheets.
 Assembly drawings.
 2-D and 3-D views.
 Methods of dimensioning.
 Methods of sectioning.
 Cross-sectional views.
 Half-sections.
 Method for indicating surface texture.
 General principles for dimensioning.
 General principles of presentation: how to present drawings.
 Linear and angular boundaries/tolerances for engineering
and technical drawings.
 Drawings for welding and metalwork.
 General scales used in drawing.
 Lines: thicknesses, spacing, and proportional dimensions.
 Lettering: dimensions and recommended sizes.

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6.0 Importance of Engineering Graphics
and Design
Just to mention a few, the importance of engineering graphics
and design include (but are not limited to) the following:
 Engineering graphics and design is important because it
provides engineering and technology students with
knowledge of techniques and standard practices generally
employed worldwide in engineering graphics and design.
This makes it easier or possible for design ideas to be
adequately communicated, produced, and used in many
countries.
 Engineering graphics and design is important because it
sharpens the imagination, and helps engineering
professionals solve more advanced technological problems
related to engineering graphics and design.

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7.0 Uses/Applications of Engineering
Graphics and Design
Although engineering graphics and design has many uses or
applications, discussions will be limited to the following:
 Engineering graphics and design can be used to produce
“layout drawings” of completely designed end products; it
can also be used in geometric studies to develop the
movement of mechanical linkages, clearances, or
arrangements.
“mono-detail drawing” which is very important because it
gives details and maximum clarity about any part of an
engineering structure without having to view a whole
structure.
“assembly drawings” for 2-D projections that have to be
joined together to form an “assembly” which gives a clear
and precise overview of structures.
“installation drawings” to provide technical information

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regarding the proper way to position and install items.
Installation drawings could also include dimensional data,
hardware descriptions, and information regarding general
configuration on installation sites where control systems,
electrical systems, hydraulic systems, and other types of
systems exist.
“modification drawings” to alter characteristics of items that
have been purchased in bulk; examples include hinges,
extrusions, channel nuts, semi-processed items as
electronic equipment drawers, castings, blank panels,
castings, etc. Drafts for altered items are usually prepared
whenever it becomes necessary to alter existing items.
“procurement control drawings” which provide criteria on
performance, and identification of supplier items that list
the engineering design characteristics required to ensure
control of interfaces, and repeatability of performance
according to design. In the commercial realm of engineering
practice, procurement control drawings can be prepared for
item identification, purchased items, alteration to

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purchased items, selection from purchased items, and
development/qualification of new items.
“mechanical systematic diagrams” whenever general
operating principles cannot be promptly determined after
studying assembly drawings. Generally, mechanical
schematic diagrams clearly illustrate design information for
hydraulic or pneumatic systems, and complex mechanical
systems such as the complex arrangement of gears, cams,
linkages, clutches, linkages, etc.
“electrical & electronic diagrams” (in accordance with ANSI
Y14.15 or ANSI/IEEE STD 991) to clearly describe the
elements and functions of electrical or electronic
tools/equipment in accordance with ANSI/IEEE STD 91 and
315.
“functional block diagrams” to clearly illustrate the
relationship between the functions of major elements in a
system, or an assembly of various systems.

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