chapter 10 convention in section - mahidol university€¦ · 3 chapter 10 conventional practice in...
TRANSCRIPT
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Example : Advantage of an oblique sketch
Isometric Oblique (cavalier)
Easier
Orthographic
Same effort
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2
RECAP
Example : Incompleted side views
Incompletedleft-side view
Incompletedright-side viewPrincipal view
Better describe an object and
facilitate dimensioning.
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Offset section : Concept & example
A section view is made by passing the bended cutting
plane completely through the part.
Example
Edge views ofthe cutting plane
are omitted
Kinds of sections
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Chapter 10
Conventional Practice in Section View
TOPICS
Section view representation
of rib, web, spoke and lug.
Aligned section
Conventional break
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Section view
representation of
rib, web, spoke and lug
TERMINOLOGY
Rib and Web are thin, flat feature of an object that
acts as a structural support.
Rib RibWeb
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Rim
Spoke is the rod radiating from the hub to the rim
of a wheel.
Spoke
Spoke
Rim
Hub
TERMINOLOGY
Hub
Lug is an ear which is built as portion of an object
for attachment.
TERMINOLOGY
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Lug is an ear which is built as portion of an object
for attachment.
TERMINOLOGY
CONVENTIONAL PRACTICE
Omit the section lines on the section view of
Rib, Web and Lug, if the cutting plane is
passed flatwise through.
Spoke, if the cutting plane is passed longwise
through.
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EXAMPLE : RIB
Normal multiview drawing
Normal section view
Section view drawing with convention
EXAMPLE : WEB : flatwise cut
Normal multiview drawing
Normal section view
Section view drawing with convention
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EXAMPLE : WEB : crosswise cut
EXAMPLE : WEB : multiple section view
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EXAMPLE : SPOKE
Misleading impression
EXAMPLE : LUG
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Aligned Section
DEFINITION
Aligned section is a section view that is drawn
by imaginary rotating the object’s features
appeared in a principal view about symmetry
axis
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Example : Hole
Gives the impression that this holes
are at unsymmetrical position.
Example : Hole
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Example : Rib
Example : Ribs & Holes
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Example : Aligned section of keywayExample : Spoke & Keyway
Example : Lug
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Conventional Break
CONVENTIONAL PRACTICE
For long objects that have to draw in a small
scale to fit them on the paper, it is recommended
to remove its long portion (which contains no
important information) and draw the break lines
at the broken ends.
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SCALE 1:1
Example
Example
SCALE 2:1
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STANDARD BREAK LINES
Rectangularcross section
Wood
Metal
Cylindricalcross section
Tubularcross section
TO DRAW CYLINDRICAL BREAK
R
R/3 R/3
30o
30o
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800
TO DIMENSION A BROKEN PART
Typicaldimensioning
method
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not to scale dimensions
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800