The Introduction of Engineering Graphics...

1. Group members Enrollment no
Prajapati Ashvinkumar 130980119079
Prajapati Hardik 130980119080
Prajapati Jay 130980119081
Prajapati Kaushik 130980119082
Branch: Mechanical
Class: B2
Semester: 2nd
Year: 2014
Topic: Introduction

2.  Engineering means “Applied science”
 Graphics means “drawings”
 “Language of Engineers”
 It is a way for communicating Engineer’s ideas, designs and
thoughts to others.
 The communication of ideas through the graphical language.
 It’s helps to reduce the time, increase the accuracy of the
object to be manufacture.

3. Freehand drawing
The lines are sketched without using instruments other
than pencils and erasers.
Example

4. Instrument drawing
Instruments are used to draw straight lines, circles, and
curves concisely and accurately. Thus, the drawings are usually
made to scale.
Example

5. Standard Code
Country Code Full name
India BIS Bureau of Indian Standards
USA ANSI American National Standard Institute
Japan JIS Japanese Industrial Standard
UK BS British Standard
Australia AS Australian Standard
Germany DIN Deutsches Institut für Normung
ISO International Standards Organization

6. Drawing Sheet
Trimmed paper of
a size A0 ~ A4.
Standard sheet size
(JIS)
A4 210 x 297
A3 297 x 420
A2 420 x 594
A1 594 x 841
A0 841 x 1189
A4
A3
A2
A1
(Dimensions in millimeters) A0

7. Drawing Scales
Length, size
Scale 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.
Size in drawing Actual size
:

8. 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 enlargement scales (X > 1)
SCALE 1:X for reduction scales (X > 1)
Dimension numbers shown in the drawing are correspond
to “true size” of the object and they are independent of
the scale used in creating that drawing.

9. Meaning of Lines
Visible lines represent features that can be seen in the
current view
Hidden lines represent features that can not be seen in
the current view
Center line represents symmetry, path of motion, centers
of circles, axis of axisymmetrical parts
Dimension and Extension lines indicate the sizes and
location of features on a drawing

10. Example : Line conventions in engineering drawing

11. Text on engineering drawing is used :
To communicate nongraphic information.
As a substitute for graphic information, in those instance
where text can communicate the needed information more
clearly and quickly.
Thus, it must be written with
Legibility - shape
- space between letters and words
Uniformity - size
- line thickness

12. Aligned Dimensioning Unidirectional Dimensioning

13. Typical Drawing Equipment
Objectives in Drawing
1. Accuracy
2. Speed
3. Legibility
4. Neatness

14.  It’s a rectangular
wooden board 22 mm
of thick and size is
650*470 mm

15. Working edge
Drawing board must be placed on the table with working edge
always to be at the left side.

16. It’s a combined form of
T-square ,Set square
Protractors and scale. One
end of the drafter is
Clamped at the left top
end.

17. High-quality drawing pencils should be used in technical drawing,
never ordinary writing pencils.
HB(soft grade) – used for lettering, freehand sketching
H ( medium grade ) - used for visible outlines, edges
2H(hard grade) - used for dimension line, hidden line

18.  The basic principle involved in arriving at the sheet size is
x1:x2 = 1:√2
 X1,X2 are sides of the sheet
 The surface area of A0 size sheet is one square meter.

20. Some drawing instruments

21.  Standard form of arrangement
 Important particulars are included
 Facilitate quick reading of important particulars – quick
references are located easily – drawings are prepared at
various locations and shared

22.  space left all around in between the trimmed edges of the sheet
a minimum of 10 mm

23. Line types

24.  Dimensions of large objects must be reduced to accommodate
on standard size drawing sheet.
 This reduction creates a scale of that reduction ratio.
 This ratio is called reducing scale
 Full scale 1:1
 Reducing scale 1:2,1:5,1:10
 Enlarging scale 2:1,5:1,10:1

25.  Point : A point is not a thing, but a place. We indicate the
position.
 Line joining of two point but no breath and think
 Polygon :it’s a plane figure more than 4 straight lines
 Depending on the number of sides the regular polygon are
classified as
1) Rectangle, 2) Pentagon, 3) Hexagon, 4) Heptagon,
5) Octagon, 6) Nonagon.
 3-1024 sides is name as polygon.

26.  Vertical plane –when the observer is viewing it from the
front.
 It shows only two dimension length and height.
 Horizontal plane – when the observer is viewing it from top.
 It shows only breath.

30.  It’s in first quadrant.
 Top view comes below to the front view

31.  It’s in third quadrant
 Top view comes above the front view

32. ENGINEERING CURVES