chapter 01 introduction

Chapter 1

Introduction

Contents

Drawing standards

Engineering drawing

Drawing sheet

Scale

Lettering

Line types

EngineeringDrawing

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

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 inEngineering 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

A drawing can be created in 3 ways

Ways to Create anEngineering Drawing

1. Freehand sketch

2. Using typical drawing instruments

3. 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 specificationof the object.

Text on drawings : Example

Generalnotes Title

block

Dimensions&

Notes

Knowledge and Skills Require

Graphicslanguage

Wordlanguage

Dimensions & Notes

Visualization is the ability to mentally picture things that do not exists.

VisualizationUsing line types

Geometricconstruction

Projectionmethod

Engineering Drawing

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.

ISO International Standards Organization

Standard Code

ANSI American National Standard InstituteUSA

JIS Japanese Industrial StandardJapan

BS British StandardUK

AS Australian StandardAustralia

Deutsches Institut für NormungDINGermany

Country Code Full name

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 StandardDrawing Sheet

Drawing standard Contents

Drawing Sheet : Standard size

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 space

Drawingspace

Title block

d

d

c

c

cBorder 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 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 represent

the “true size” of an object and they are independent of

the 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 StandardLettering


- Size (or text height)

- line thickness

- Shape

- Space between letters

- Space between words

Recommendation

Legibility

Uniformity

Text’s style on the drawing

must have the following

2 properties

Examples

GOOD

Not uniform in style.

Not uniform in height.

Not uniformly vertical.

Not uniform inthickness of stroke.

Inappropriate spacebetween 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 CurvedHorizontal

1 1 2

3

“I” letter “A” letter

1

2

3

4 5

6

“B” letter

Examples

Suggested Strokes SequenceStraight 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


Skip section

N M K Z

Y A 4


Skip section

O Q C G


Skip section

D U P B

R J


Skip section

5 7


1 2

Skip section

6

8 9

0S 3


Skip section

l i

Stroke Sequence : Lower-case

Skip section

v w x k

z


Skip section

j y f

r

t


Skip section

c o a b

d p q e


Skip section

g n m h

u s


Skip section

DRAWING

Word Composition

Non-uniformspacing

Uniformspacing DR A WING

Space between the letters depends on the adjacent

contour of the letters.

Word having non-uniform spacing is more readable.

Word Composition

Contour

DRAWINGContour can be denoted as “straight”, “slant” and “curve”.

Adjacent contour can be1. 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.

Spa

cing

Leave the space between words equal to the spacerequires for writing a letter “O”.

Example

Sentence Composition

ALL DIMENSIONS ARE INMILLIMETERS

O O OO UNLESS

OTHERWISE SPECIFIED.O

Drawing StandardLine Types


Basic Line Types &Name according to application

Continuous

DashChain

Style

Thickness Thick Thin 1. Dimension line2. Extension line3. 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

chapter 01 introduction

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