Transcript Chapter 1 Introduction Contents Engineering drawing Drawing standards Drawing sheet Scale Lettering Line types Engineering Drawing The words of the language, as they are written or spoken, do not.

Chapter 1
Introduction
Contents
Engineering drawing
Drawing standards
Drawing sheet
Scale
Lettering
Line types
Engineering
Drawing
The words of the language, as they are written or spoken, do not seem to play any role in my
mechanism of thought. The psychical entities which seem to serve as elements in thought are
certain signs and more or less clear images which can be “voluntarily” reproduced and
combined--this combinatory play seems to be the essential feature in productive thought before
there is any connection with logical construction in words or other kinds of signs which are
communicated to others
--Albert Einstein
Contents
Effectiveness of Graphic Language
1. Try to write a description of
this object.
2. Test your written description
by having someone attempt
to make a sketch or visualize
from your description.
You can easily understand that …
The word language is inadequate for describing the size,
shape and features completely as well as concisely.
Graphic Language in
Engineering Drawing
“Engineering drawing” or “blueprint” uses lines to
represent the features of an object.
Features of an object are surface (include plane) and
edge.
Surface
Edge
Ways to Create an
Engineering Drawing
A drawing can be created in 3 ways
1. Freehand sketch
2. Using typical drawing instruments
3. Using a computer
Create a Drawing : Freehand sketch
The lines are drawn using only pencil and erasers on a
blank or grid paper.
Example
Pictorial sketch
Orthographic sketch
Create a Drawing : Using instruments
Drawing instruments are used to
draw straight lines, circles, and
curves concisely and accurately.
Drawings are usually made to scale.
Example
Create a Drawing : Using a computer
Computer aided drafting (CAD) software is used.
Example
2D drawing
Solid modeling
Elements of a Drawing
A clear and precise engineering drawing requires both
graphics and word languages.
Graphics language
Describe a shape (mainly).
Word language
Describe an exact size,
location and specification
of the object.
Text on drawings : Example
Dimensions
&
Notes
General
notes
Title
block
Knowledge and Skills Require
Engineering Drawing
Word
language
Graphics
language
Geometric
construction
Using line types
Projection
method
Dimensions & Notes
Visualization
Visualization is the ability to mentally picture things that do not exists.
Contents
Drawing Standard
Drawing sheet
Scale
Lettering
Line types
Contents
Definition and Necessity
Drawing standards are set of rules that govern how
technical drawings are represented.
Drawing standards are used so that drawings convey
the same meaning to everyone who reads them.
Standard Code
Country
Thailand
USA
Code
Full name
มอก./TIS สำนักงำนมำตรฐำนผลิตภัณฑ ์อุต
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
Examples of TIS Standard
Contents
Code number
มอก. 210 2520
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Examples of JIS Standard
Contents
Code number
JIS Z 8311
Sizes and Format of Drawings
JIS Z 8314
Scales
JIS Z 8312
Line Conventions
JIS Z 8313
Lettering
JIS Z 8315
Projection methods
JIS Z 8316
Presentation of Views and Sections
JIS Z 8317
Dimensioning
Drawing Standard
Drawing Sheet
Drawing standard
Contents
Drawing Sheet : Standard size
Trimmed paper of
a size A0 ~ A4.
Standard sheet size
(JIS)
A4
A3
A2
A1
A0
210 x 297
297 x 420
420 x 594
594 x 841
841 x 1189
A4
A3
A2
A1
A0
(Dimensions in millimeters)
Drawing Sheet : Orientation & Margin
c
1. Type X (A0~A4)
Border d
lines
c
c
Drawing space
Sheet size
Title block
2. Type Y (A4 only)
d
Drawing
space
Title block
A4
A3
A2
A1
A0
c (min) d (min)
10
10
10
20
20
25
25
25
25
25
Drawing Standard
Drawing Scale
Drawing standard
Contents
Drawing Scales : Definition
Length, size
Scale is a ratio between the linear dimension of a
drawn representation of an object and the actual object.
1
Drawing
:
2
Actual
Drawing Scales : Designation
Designation of a scale consists of the word “SCALE”
followed by the indication of its ratio, as follows
SCALE 1:1 for full size
SCALE X:1 (X > 1) for an enlargement scales
SCALE 1:X (X > 1) for a reduction scales
Drawing scale is commonly found in a title block.
Drawing Scales : Notes
Dimension numbers shown in the drawing represent
the “true size” of an object and they are independent of
the drawing scale used.
Drawing Scales : Standard scale
Standard reducing scales are
1:2, 1:5, 1:10, 1:20, 1:50, 1:100
Standard enlarging scales are
2:1, 5:1, 10:1, 20:1, 50:1, 100:1
Drawing Standard
Lettering
Drawing standard
Contents
Recommendation
Text’s style on the drawing
must have the following
Examples
GOOD
2 properties
Not uniform in style.
Legibility
- Shape
Not uniform in height.
- Space between letters
- Space between words
Uniformity
- Size (or text height)
- line thickness
Not uniformly vertical.
Not uniform in
thickness of stroke.
Inappropriate space
between letters
Style (this course)
Gothic vertical style.
Begin the sentence, phrase or word with a capital letter.
Text height 2~3 mm.
Space between lines of text is about of text height.
Height of the lower-case letter is about 2/3 of that of a
capital letter.
Basic Strokes
Straight
Slanted
Horizontal
Curved
Examples
“I” letter
1
“A” letter
2
1
“B” letter
1
4
3
3
2
5
6
Upper-caseStrokes
Letters &Sequence
Numerals
Suggested
Straight line
letters
Curved line
letters
&
Numerals
Lower-case Letters
Stroke Sequence : Upper-case
I
L
E
H
T
F
Skip section
Stroke Sequence : Upper-case
V
X
W
Skip section
Stroke Sequence : Upper-case
N
M
K
Y
A
4
Z
Skip section
Stroke Sequence : Upper-case
O
Q
C
G
Skip section
Stroke Sequence : Upper-case
D
U
R
J
P
B
Skip section
Stroke Sequence : Upper-case
1
2
5
7
Skip section
Stroke Sequence : Upper-case
S
0
8
9
3
6
Skip section
Stroke Sequence : Lower-case
l
i
Skip section
Stroke Sequence : Lower-case
v
w
x
k
z
Skip section
Stroke Sequence : Lower-case
j
y
f
t
r
Skip section
Stroke Sequence : Lower-case
c
o
a
b
d
p
q
e
Skip section
Stroke Sequence : Lower-case
g
u
n
m
h
s
Skip section
Word Composition
Space between the letters depends on the adjacent
contour of the letters.
Non-uniform
spacing
Uniform
spacing
DRAWING
D R A W IN G
Word having non-uniform spacing is more readable.
Word Composition
DRAWING
Contour
Contour can be denoted as “straight”, “slant” and “curve”.
Adjacent contour can be
: II, IN, IM, IP etc.
2. straight-curve (or curve-straight) : IO, QR etc.
3. straight-slant (or slant-straight)
: IV, IW etc.
4. curve-curve
: OO, OG etc.
5. slant-curve (or curve-slant)
: VO, WG, VC etc.
6. slant-slant
: VW, VX etc.
Spacing
1. straight-straight
Sentence Composition
Leave the space between words equal to the space
requires for writing a letter “O”.
Example
ALL ODIMENSIONS OARE OIN
MILLIMETERS OUNLESS
OTHERWISE O SPECIFIED.
Drawing Standard
Line Types
Drawing standard
Contents
Basic Line Types &
Name according to application
Thickness
Thick
Thin
Visible line
Style
Continuous
Dash
Chain
1. Visible line
1. Dimension line
2. Extension line
3. Leader line
Hidden line
Center line
represent features that can be seen in the current view.
2. Dimension line
Extension line indicate the sizes and location of features.
Leader line
3. Hidden line
represent features that can not be seen in the current view.
4. Center line
represents symmetry, path of motion, centers of circles,
axis of axisymmetrical parts
Example
Contents