Introduction

Chapter 1 Introduction

Drawing standards
Engineering drawing
Drawing sheet
Scale
Lettering
Line types

Contents

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

EngineeringDrawing

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.
Effectiveness of Graphic Language
The word language is inadequate for describing the size, shape and features completely as well as concisely.
You can easily understand that …

Graphic Language in Engineering Drawing

“Engineering drawing” or “blueprint” uses lines torepresent the features of an object. Features of an object are surface (include plane) and edge.
Surface
Edge

A drawing can be created in 3 ways

Ways to Create an Engineering Drawing
Freehand sketch Using typical drawing instruments Using a computer

Example

Create a Drawing : Freehand sketch
The lines are drawn using only pencil and erasers on a blank or grid paper.
Pictorial sketch
Orthographic sketch

Example

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.
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

General notes
Title block
Dimensions & Notes

Knowledge and Skills Require

Graphics language
Word language
Dimensions & Notes
Visualization is the ability to mentally picture things that do not exists.
Visualization
Using line types
Geometric construction
Projection method
Engineering Drawing
Contents

Drawing sheet

Scale
Lettering
Line types
Contents

Drawing Standard

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.

Definition and Necessity

ISO
International Standards Organization
Standard Code
ANSI
American National Standard Institute
USA
JIS
Japanese Industrial Standard
Japan
BS
British Standard
UK
AS
Australian Standard
Australia


DIN
Germany
Country
Code
Full name
มอก./TIS สำนักงานมาตรฐานผลิตภัณฑ์อุตสาหกรรม Thailand

Examples of TIS Standard

มอก. 210 2520 วิธีเขียนแบบทั่วไป : ทางเครื่องกล มอก. 440 ล.1 2541การเขียนแบบก่อสร้างเล่ม 1 ทั่วไป มอก. 446 ล.4 2532ข้อแนะนำสำหรับการเขียนแผนภาพวงจรไฟฟ้า มอก. 1473 2540 การเขียนแบบเทคนิค การติดตั้งสัญลักษณ์สำหรับระบบท่อของเหลวระบบทำความร้อน การระบายอากาศและระบบท่ออากาศ Code number
Contents
ที่มา : http://library.tisi.go.th/data/lib_resources/pdf/catalog-online49/tis/02_ICS.pdf

JIS Z 8311 Sizes and Format of Drawings

JIS Z 8312 Line Conventions
JIS Z 8313 Lettering
JIS Z 8314 Scales
JIS Z 8315 Projection methods
JIS Z 8316 Presentation of Views and Sections
JIS Z 8317 Dimensioning
Code number
Contents
Examples of JIS Standard

Drawing standard

Contents

Drawing StandardDrawing 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
A0
(Dimensions in millimeters)

Drawing Sheet : Standard size

Drawing space
Drawing space
Title block
d
d
c
c
c
Border lines
1. Type X (A0~A4)
2. Type Y (A4 only)
Title block
Sheet size c (min) d (min) A4 10 25 A3 10 25 A2 10 25 A1 20 25 A0 20 25
Drawing Sheet : Orientation & Margin

Drawing standard

Contents

Drawing StandardDrawing Scale

Drawing Scales : Definition

Drawing
Actual
Length, size
:
Scale is a ratio between the linear dimension of a drawn representation of an object and the actual object.
1
2


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 Scales : Designation
Drawing scale is commonly found in a title block.


Dimension numbers shown in the drawing representthe “true size” of an object and they are independent ofthe drawing scale used. Drawing Scales : Notes

Standard reducing scales are 1:2, 1:5, 1:10, 1:20, 1:50, 1:100

Drawing Scales : Standard scale
Standard enlarging scales are 2:1, 5:1, 10:1, 20:1, 50:1, 100:1

Drawing standard

Contents

Drawing StandardLettering

- Size (or text height)- line thickness
- Shape Space between letters Space between words
Recommendation
Legibility
Uniformity
Text’s style on the drawingmust have the following2 properties Examples
GOOD
Not uniform in style.
Not uniform in height.
Not uniformly vertical.
Not uniform in thickness of stroke.
Inappropriate space between letters

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.

Style (this course)

Straight
Slanted
Curved
Horizontal
1
1
2
3
“I” letter “A” letter 1
2
3
4
5
6
“B” letter Examples

Basic Strokes

Suggested Strokes Sequence
Straight line letters
Curved line letters & Numerals
Upper-case Letters & Numerals

Lower-case Letters

I
L
T
F
E
H
Stroke Sequence : Upper-case
Skip section



V
X
W
Stroke Sequence : Upper-case
Skip section


N
M
K
Z
Y
A
4
Stroke Sequence : Upper-case
Skip section


O
Q
C
G
Stroke Sequence : Upper-case
Skip section



D
U
P
B
R
J
Stroke Sequence : Upper-case
Skip section


5
7
Stroke Sequence : Upper-case
1
2
Skip section


6
8
9
0
S
3
Stroke Sequence : Upper-case
Skip section



l
i
Stroke Sequence : Lower-case
Skip section


v
w
x
k
z
Stroke Sequence : Lower-case
Skip section


j
y
f
r
t
Stroke Sequence : Lower-case
Skip section



c
o
a
b
d
p
q
e
Stroke Sequence : Lower-case
Skip section


g
n
m
h
u
s
Stroke Sequence : Lower-case
Skip section

DRAWING

Word Composition
Non-uniform spacing
Uniform spacing
D
R
A
W
I
N
G
Space between the letters depends on the adjacent contour of the letters.
Word having non-uniform spacing is more readable.

Word Composition

Contour
DRAWING
Contour can be denoted as “straight”, “slant” and “curve”. Adjacent contour can be 1. straight-straight : 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



Leave the space between words equal to the spacerequires for writing a letter “O”. Example
Sentence Composition
ALL
DIMENSIONS
ARE
IN
MILLIMETERS
O
O
O
O
UNLESS
OTHERWISE
SPECIFIED.
O

Drawing standard

Contents

Drawing StandardLine Types

Basic Line Types & Name according to application
Continuous
Dash
Chain
Style
Thickness
Thick
Thin
1. Dimension line 2. Extension line 3. Leader line
Center line
Hidden line
Visible line
represent features that can be seen in the current view.
represent features that can not be seen in the current view.
represents symmetry, path of motion, centers of circles, axis of axisymmetrical parts
indicate the sizes and location of features.
1. Visible line
3. Hidden line
4. Center line
2. Dimension line Extension line Leader line

Example

Contents