ENGR 2
Engineering Graphics
Week #1
Lecture Notes
Many of the materials provided in this lecture are provided by
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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Class Policies
Everything is posted on the class web site.
http://www.mpcfaculty.net/steven_pearce
Review course outcomes.
The class is a work in progress. Lecture, lab, and
homework information will be posted as it is
developed
The only enrollment restriction is that the class is
limited to students who are currently accepted into
a School of Engineering degree program.
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Class Overview
The intent of this course is to teach ENGINEERS
how to communicate by graphical means.
This NOT an AutoCAD class!
Yes… we use AutoCAD in the class, but there is no
attempt to make you proficient in it’s use.
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Graphics communication using engineering
drawings and models is a language, a clear,
precise language with definite rules that must
be mastered if you are to be successful in
engineering design.
Once you know the language of graphics
communications, it will influence the way you
think, the way you approach problems. Why?
Because humans tend to think using the languages
they know. Thinking in the language of
engineering graphics, you will visualize problems
more clearly and will use graphic images to find
solutions with greater ease.
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In engineering, 92 percent of the
design process is graphically based.
The other 8 percent is divided between
mathematics, and written and verbal
communications. Why? Because
graphics serves as the primary means
of communication for the design
process.
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Fig. 1.7
Drafting and documentation, along with design modeling,
comprise over 50 percent of the engineer's time and are purely
visual and graphical activities. Engineering analysis depends
largely on reading engineering graphics, and manufacturing
engineering and functional design also require the production and
reading of graphics.
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Courtesy of the Grumman Aerospace Corporation
Engineering graphics can
also communicate
solutions to technical
problems. Such
engineering graphics are
produced according to
certain standards and
conventions so they can
be read and accurately
interpreted by anyone
who has learned those
standards and
conventions.
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A designer has to
think about the many
features of an object
that cannot be
communicated with
verbal descriptions.
Technical drawings
are a nonverbal
method of
communicating
information.
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Engineers are creative people who use technical
means to solve problems. They design products,
systems, devices, and structures to improve our
living conditions.
Technologists assist engineers and are concerned
with the practical aspects of engineering in
planning and production. Both engineers and
technologists are finding that sharing technical
information through graphical means is becoming
more important as more non-technical people
become involved in the design/manufacturing
process.
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Fig. 1.14
Spoken language and writing are highly refined communications
systems that humans use to express emotions, information, and
other needs. Mathematics is an abstract, symbol-based
communications system built on formal human logic. Graphics is
a visual communications language incorporating text, images, and
numeric information.
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Engineering graphics is a real and complete language
used in the design process for:
1. Communicating
2. Solving problems
3. Quickly and accurately visualizing objects.
4. Conducting analyses.
Fig. 1.24
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Fig. 1.20
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• Visual science is the study of the visual and technical applications of graphics. Visualization is the process of
mentally understanding visual information. Geometry is a branch of mathematics that deals with the properties,
relationships, and measurements of points, lines, angles, planes, and solids. Visualization ability and a knowledge
of geometry combine to create both artistic and technical drawings.
• Artistic drawings are used to express aesthetic, philosophical, and abstract ideas, while technical graphics or
technical drawing is a specialized type of graphics used to communicate technical information.
• Plane geometry - the geometry of planar figures, such as circles and triangles, and their relationships.
• Solid geometry - the geometry of three-dimensional objects, such as cylinders, cubes and spheres, and their
relationships.
• Analytic geometry - the analysis of geometric structures and properties, principally using algebraic operations
and position coordinates.
• Descriptive geometry - the science of analyzing and solving space distances and relationships, using graphics.
• Conventions are commonly accepted practices, rules, or methods used in technical drawing.
• Standards are sets of rules that govern how technical drawings are represented. Standards allow for the clear
communication of technical ideas. In the United States, the American National Standards Institute (ANSI) is the
governing body that sets the standards used for engineering and technical drawings.
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A drawing is a graphical
representation of objects
and structures and is done
using freehand,
mechanical, or computer
methods. Drawings may
be abstract, such as the
multiview drawings, or
more concrete, such as
very sophisticated
computer models.
Fig. 1.25
Technical drawing is used to represent complex technical ideas
with sufficient precision for the product to be mass-produced
and the parts to be easily interchanged.
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Reprinted from ASMEY 14.5M-1994, Dimensioning and Tolerancing,
by permission of The American Society of Mechanical Engineers
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Mechanical engineering comprises a wide range of activities that
include the research, design, development, manufacture, management,
and control of engineering systems and their components. Mechanical
engineers use a wide variety of mechanical drawings and computer
models for design and analysis.
Electrical engineering includes the research, design, development,
marketing, field testing, and operation and maintenance of electrical
and electronic systems and their components. Electrical engineers use
schematic drawings and electromechanical drawings of electrical
systems for communications.
Civil engineering involves the planning, design, construction,
operation, and maintenance of transportation, environmental, and
construction systems. Civil engineers use working drawings of
construction systems, map drawings, and other detail drawings for
communications.
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As a student of engineering graphics, you will study and learn to apply
the tools used to create engineering drawings and models. Even more
important, you will also learn the underlying principles and concepts
of engineering graphics, such as descriptive geometry. You will also
learn the standards and conventions that will enable you to create
drawings and models that can be read and accurately interpreted by
engineers or technologists anywhere.
The ability to draw is a powerful skill. It gives a person’s thoughts
visible form. Engineering drawings can communicate complex ideas
both efficiently and effectively, and it takes special training to be able to
produce these complex images. If drawings are “windows to our
imaginations,” then engineering drawings are specialized windows that
give expression to the most complex, technical visions our minds can
imagine. Engineering drawing does more than communicate. Like any
language, it can actually influence how we think. Knowing how to draw
allows you to think of and deal with many problems that others may not.
A knowledge of technical graphics helps you more easily envision
technical problems, as well as their solutions. In short, engineering
graphics is a necessity for every engineer and technologist
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Technical graphics is an integral part of the
engineering design process through which
engineers and drafter/designers generate new
ideas and solve problems. Traditional
engineering design consists of closely related
steps that flow both sequentially and back and
forth. Many industries in the United States
are changing their design methodology from
a linear/sequential activity to a team approach
in which all parts of the company are working
on a project simultaneously.
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Design is the process of conceiving or inventing ideas mentally and
communicating these ideas to others in a form that is easily understood.
Most often the communications tool is graphics.
Design is used for two primary purposes: personal expression, and
product or process development.
Design for personal expression, usually associated with art, is divided
into concrete (realistic) and abstract design and is often a source of
beauty and interest.
When a design serves some useful purpose, such as the shape of a new
automobile wheel, it is classified as a design for product or process
development.
Fig. 2.1
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Fig. 2.2
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Engineering Design Components
Aesthetic design is concerned with the look and
feel of a product.
Functional design is concerned with the
function of a product or process. Function
means that a product possesses a form related
directly to the purpose of that product.
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Aesthetic design
Form is the overall physical appearance of a product and consists of many elements, the
arrangement of which is critical to the aesthetics and function of the product. These elements
are:
• Unity is the use of similar elements throughout the design or product line. The engineer
accomplishes unity by thinking of the product as a whole instead of as individual parts or
components.
• Style is the addition of decoration to a product and is closely linked to marketing.
• Line is another characteristic of a product.
• Space is the relationship of a product to its background, as well as to its negative elements
(holes, slots, voids).
• Mass is the design element that provides a sense of weight or heaviness.
• Proportion is the relationship of the smaller elements to the whole design.
• Balance is the design element that gives the product equilibrium.
• Contrast is the feature used to emphasize or de-emphasize certain elements in a design.
• Color is the element used to evoke emotions, give sensations of weight, and enhance a
design form.
Fig. 2.4
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© Michael Rosenfeld: Stone
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Engineering design is a problem-solving process that uses knowledge, resources,
and existing products to create new goods and processes. Engineering design has
both aesthetic and functional elements and can be broken into two broad
categories: product design and system design.
Product Design is the process used to create new products, such as a new
automobile model, a new appliance, and a new type of wheelchair. Product design
is a complex activity that includes market, production, sales, service, function, and
profit analyses used to produce a product that meets the wants and needs of the
consumer, is economically produced, is safe for the consumer and the environment,
and is profitable to the company.
System design is the process used to create a new system or process. A system is
an orderly arrangement of parts that are combined to serve one general function.
Examples of the system designs are: the arrangement of the assembly process in a
factory; the heating, ventilation, and air-conditioning (HVAC) system in a
structure; and the electrical system in the automobile.
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Engineering design is one of the processes normally associated with the
entire business or enterprise, from receipt of the order or product idea, to
maintenance of the product, and all stages in between. An engineering
design involves both a process and a product. A process is a series of
continuous actions ending in a particular result. A product is anything
produced as a result of some process. Graphics is an extremely important
part of the engineering design process, which uses graphics as a tool to
visualize possible solutions and to document the design for
communications purposes.
Traditional engineering design is a linear approach divided into a number
of steps. For example, a six-step process might be divided into: problem
identification, preliminary ideas, refinement, analysis, documentation, and
implementation. The design process moves through each step in a
sequential manner; however, if problems are encountered, the process may
return to a previous step. This repetitive action is called iteration or
looping.
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Traditional engineering design is a
linear approach divided into a
number of steps.
For example, a six-step process
might be divided into: problem
identification, preliminary ideas,
refinement, analysis,
documentation, and
implementation. The design
process moves through each step
in a sequential manner; however, if
problems are encountered, the
process may return to a previous
step. This repetitive action is called
iteration or looping.
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Concurrent engineering is a nonlinear team
approach to design that brings together the
input, processes, and output elements necessary
to produce a product.
The concurrent engineering model shows how
every area in an enterprise is related, and the
CAD database is the common thread of
information between each area.
Fig. 2.7
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The engineering design process
consists of three overlapping areas:
ideation, refinement, and
implementation which all share the
same CAD database.
Current engineering design practices
makes use of a number of new
practices, including Intranets and
Extranets, e-Business, and the Digital
Enterprise.
Fig. 2.8
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