Study Lesson 1 Introduction. Contents Drawing standards Engineering drawing Drawing sheet Scale...
-
Upload
ethelbert-fleming -
Category
Documents
-
view
267 -
download
11
Transcript of Study Lesson 1 Introduction. Contents Drawing standards Engineering drawing Drawing sheet Scale...
Study Lesson 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 sizesize,
shapeshape and featuresfeatures completely as well as concisely.
You can easily understand that …
Graphic Language inEngineering Drawing
“Engineering drawing” or “blueprint” uses llinesines to
represent the features features of an object.
Features of an object are surface surface (include planeplane) and
edgeedge.
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 conciselyconcisely and accuratelyaccurately.
Drawings are usually made to scalemade 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 graphics and word 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
VisualizationVisualization 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 rulesset of rules that govern how
technical drawings are represented.
Drawing standards are used so that drawings conveyconvey
the same meaningthe 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
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 standard Contents
Drawing Scales : Definition
Drawing Actual
Length, size
:
ScaleScale 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 enlargementenlargement scales
SCALE 1:X (X > 1) for a reductionreduction scales
Drawing Scales : Designation
Drawing scale is commonly found in a title block.
Dimension numbersDimension 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
Drawing standard Contents
- Size (or text height)
- line thickness
- Shape
- Space between letters
- Space between words
Recommendation
LegibilityLegibility
UniformityUniformity
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
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
0S 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-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
Drawing standard Contents
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