CE En 112 Engineering Drawing with CAD Application

Chapter 1: Introduction to Graphics Communication

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Lecture Outline

• Introduction (1.1 – 1.5, 1.7)

• What will you learn? (1.9)

• Drawing tools (1.8)

• Media (1.8.2)

• Alphabet of lines (1.6)

• Scales (1.8.3 – 1.8.5)

• Next class

Section numbers shown here apply to Chapter 1 of Textbook (B) from Bertoline-Wiebe-Miller “Fundamentals of Graphics Communication, 3/e)

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After completing this chapter, you will be able to:

1. Describe why the use of graphics is an effective means of communicating when designing

2. Define standards and conventions as applied to technical drawings

3. Describe the design process4. Identify the important traditional tools used to create

technical drawings5. Use sketching to draw lines, circles, arcs, and curves6. Read and use scales7. Identify the types and thickness of the various lines in the

alphabet of lines8. Create a design sketch using pencil9. Identify and use sketching tools10. Follow good hand-lettering practice

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Introduction (1.1-1.5, 1-7)

• Engineers: Creative people who use technical means to solve problems. They design products, systems, devices, and structures to improve our living conditions. (p.4)

• Technical Drawings: a clear, precise language (non-verbal) used in the design process for communicating, solving problems, quickly and accurately visualizing objects, and conducting analyses

• A graphical representation of objects and structures is done using freehand, mechanical, or computer methods

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Introduction (con’t)

• 92% of the design process is graphical• The remaining 8% is mathematics and written

communicationBreakdown of Engineer’s time

Who uses engineering graphics?

All aspects include graphics communicationFig. 1.1

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Introduction (con’t)

• Practice Exercise 1.1– Attempt to describe

the part shown in this figure verbally to the person seatednext to you

– How easy is it to describe a part such as this without the use of graphics?

Fig. 1.89

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Introduction (con’t)

Traditional: A linear, segmented activity involving problem identification, preliminary ideas, design refinements, analysis, optimization, and documentation

Concurrent: A team activity involving coordination of the technical and non-technical functions of design and manufacturing within a business

The CAD database becomes a communication medium.

An evolving design process:

Fig. 1.12 Fig. 1.14 Fig. 1.15

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What Will You Learn? (1.9)

Visualization Learn to mentally control visual information

Graphics theory

Learn to construct engineering geometry and master basic projection techniques

Standards Learn a set of rules that govern how parts are made and technical drawings are represented

Conventions Master commonly accepted practices and methods used for technical drawings

Tools Learn how to use drafting tools, both hand-held and computer tools

Applications Learn how technical graphics are used in engineering design

CE En 112

Manual Drafting

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What Will You Learn? (con’t)

Artistic drawing vs. Technical drawing

What’s the difference?

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What Will You Learn? (con’t)

Parallel projection Orthographic Axonometric (Isometric)

Multiview (& auxiliary)

Oblique Cabinet

Cavalier

Perspective projection Linear One-point

Two-point

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What Will You Learn? (con’t)

Multiview vs. Isometric

Cavalier vs. Cabinet oblique

Perspective vs. Oblique

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What Will You Learn? (con’t)

Drawing Conventions (1.5): commonly accepted practices, rules, or methods (e.g., dashed line for hidden feature)

Standards (1.5): set of rules that govern how technical drawings are represented (e.g., ANSI standards)

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Drawing Tools (1.8)

Two mechanical pencils: 0.7 and 0.5 mm, or 0.5 and 0.3 mm combinations; Pencil grades – HB and H, or F and 2H combinations

One compass and one divider

One set of 45- and 30/60-degree triangles

Two scales (one English unit and one Metric unit)

One irregular curve (French curve)

One protractor

One good eraser (and if you can afford, one erasing shield)

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Drawing Tools (con’t)

The use of drafting tools

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Media (1.8.2)

• Media: surfaces upon which an engineer or technologist communicates graphical information. Different types include:– Tracing paper (a thin, translucent paper used for detail

drawings)– Vellum (tracing paper chemically treated to improve

translucency)– Polyester film (transparent, waterproof, and difficult to

tear, “Mylar”)

• The American National Standard Institute (ANSI) has established standard sheet sizes and title blocks for media used in technical drawings

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Media (con’t)

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Alphabet of Lines (1.6)

• Pencil Grades

• Line Weight

Remember that Accuracy, Neatness, and Speed count in technical drawing

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Alphabet of lines (con’t)

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Alphabet of lines (con’t)

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Alphabet of lines (con’t)

• AutoCAD®

Linetypes

ACAD ISO series lines are very large.

For this class, use standard line types starting from BORDER to PHANTOM lines.

We will see these line types in AutoCAD.

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Scales (1.8.3 – 1.8.5)

• Civil Engineering Scale

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Scales (con’t)

• Reading a civil engineer’s scale

Refer to the Chapter 1 Supplement for other types of scales.

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Next Manual Drafting Lecture (Jan 29)

• Purchase drafting tools needed for manual drafting portion of class if you have not done so

• Read Chapter 2 in the graphics communication book