Fundamentals of Engineering Drawing Notes for Al Tech by Hafeel Sir

8/11/2019 Fundamentals of Engineering Drawing Notes for Al Tech by Hafeel Sir

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ENGINEERING DRAWING

SKV 1021

7/12/2007 1

Prepared by :

AZIZUL AZRI BIN MUSTAFFAB.Sc.(Hons.), M.Sc.(Chem.Eng.)(UTM)

Last Updated: July 2007

ENGINEERING THE RESOURCESENGINEERING THE RESOURCES


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CHAPTER 2FUNDAMENTALS OF

ENGINEERINNG DRAWING

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LEARNING OUTCOMES

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INTRODUCTION TO ENG. DRAWING

It is expected that students will be able to:

Identify and using the basics ofengineering drawing



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FUNDAMENTALS OF ENG. DRAWING

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INTRODUCTION

ALPHABETS AND NUMBERS ENGINEERING DRAWING LAYOUT

TYPES OF LINES SCALES

DIMENSIONING

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INTRODUCTION

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Elements of Engineering DrawingEngineering drawing are made up of graphicsraphics

languageanguage and word languageord language .

GraphicslanguageDescribe a shape(mainly).

Wordlanguage

Describe size, location andspecification of the object.



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INTRODUCTION (contd)

Basic Knowledge for Drafting

Wordlanguage

Graphicslanguage

Linetypes

Geometricconstruction Lettering

Projectionmethod

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ALPHABETS AND NUMBERS

Text on DrawingsText on engineering drawing is used :

To communicate nongraphic information.

As a substitute for graphic information, in those

instance where text can communicate the neededinformation more clearly and quickly.

Thus, it must be written with

Uniformityniformity - size - line thickness

Legibilityegibility - shape - space between letters and words



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ALPHABETS AND NUMBERS (contd)

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Example Placement of the text on drawing Dimension &Notes

Notes Title BlockENGINEERING THE RESOURCESENGINEERING THE RESOURCES


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ALPHABETS AND NUMBERS (contd)

Lettering StandardThis courseANSI Standard

Use a Gothic text style,

either inclined or vertical.

Use all capital letters.Use 3 mm for most

text height.

Space between lines

of text is at least 1/3

of text height.

Use only a Normal

text style .

Use both capital andlower-case letters.For letters in title block it is

recommend to use 5 mmtext height



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ENGINEERING DRAWING LAYOUT

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Organization/Company

Title of Drawing

Details of the drawer& the drawing

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TYPES OF LINES

Basic Line Types

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Types of Lines Appearance Name accordingto application

Continuous thick line Visible lineContinuous thin line Dimension line

Extension line

Leader line

Dash thick line Hidden line

Chain thin line Center line



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TYPES OF LINES (contd)

Visible linesisible lines represent features that can be seen in the

current view

Meaning of Lines

Hidden linesidden lines represent features that can not be seen in

the current view

enter lineenter line represents symmetry, path of motion, centers

of circles, axis of axisymmetrical parts

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Dimension and Extension linesimension and Extension lines indicate the sizes and

location of features on a drawingENGINEERING THE RESOURCESENGINEERING THE RESOURCES


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TYPES OF LINES (contd)

Example : Line conventions in engineering drawing



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SCALES

Drawing Scales

Scalecale is the ratio of the linear dimension of an element

of an object shown in the drawing to the real linear

dimension of the same element of the object.

Length, size

Size in drawing Actual size

:



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SCALES (contd)

Drawing Scales

Designation of a scale consists of the word SCALE

followed by the indication of its ratio , as follow

SCALE 1:1 for full size

SCALE X:1 for enlargementnlargement scales (X > 1)

SCALE 1: X for reductioneduction scales (X > 1)

Dimension numbers shown in the drawing are correspond

to true size of the object and they are independent of

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DIMENSIONING

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ENGINEERING DESIGN

TRANSFERREDINFORMATION

PROCESS RESULT

Designa part Sketches

of ideas

ShapeMultiviewDrawing

Dimensioning

1. Size, Location

2. Non-graphicinformation

Createdrawings

Manufacture



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DEFINITION

Dimensioning is the process of specifying parts

information by using of figures , symbols and notes .

This information are such as:

1. Sizes and locations of features

2. Materials type

3. Number required

4. Kind of surface finish

5. Manufacturing process

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DIMENSIONING SYSTEM

1. Metric system : ISO and JIS standards

32, 32.5, 32.55, 0.5 (not .5) etc.Examples

Thiscourse

2. Decimal-inch system

0.25 (not .25) , 5.375 etc .Examples

3. Fractional-inch system

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4

1 ,Examples etc.



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DIMENSIONING COMPONENTS

Extension lines

Dimension lines(with arrowheads)

Leader lines

Continuousthin line

Dimension figures

Notes : - local note

- general note

Using textfunction



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EXTENSION LINES

indicate the location on the objects features that are

dimensioned.



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DIMENSION LINES

indicate the direction and extent of a dimension, and

inscribe dimension figures .

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43

1 31 2 3

o



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LEADER LINES

indicate details of the feature with a local note.

10 27

43

1 31 2

3 o

10 Drill, 2 Holes

R16



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PLACEMENT OF

DIMENSION

Last Updated: July 2007 ENGINEERING THE RESOURCESENGINEERING THE RESOURCES


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RECOMMENDED PRACTICE

1. Extension lines, leader lines should not cross

dimension lines.

POOR GOOD



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2. Extension lines should be drawn from the nearest

points to be dimensioned.

POOR GOOD



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3. Extension lines of internal feature can cross visible

lines without leaving a gap at the intersection point.

WRONG CORRECT



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4. Do not use object line , center line , and dimensionline as an extension lines.

POOR

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GOOD


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5. Avoid dimensioning hidden lines.

POORGOOD

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6. Place dimensions outside the view, unless

placing them inside improve the clarity.

POOR GOOD




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6. Place dimensions outside the view, unless

placing them inside improve the clarity .

JUST OK BETTER

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7. Apply the dimension to the view that clearly show

the shape or features of an object .

POOR GOOD




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8. Dimension lines should be lined up and grouped

together as much as possible.

POOR GOOD




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9. Do not repeat a dimension.

POOR GOOD



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END

OF

CHAPTER 2


Fundamentals of Engineering Drawing Notes for Al Tech by Hafeel Sir

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