Week 7_MIET2093_Section Views

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MIET2012 
1 
Lecture 7: Section Views 
MIET2093 
Computer Aided Design 
 
by: 
Dr. Toh Yen Pang 
tohyen.pang@rmit.edu.au 
9925 6128 
B251.3.22 
School of Aerospace, Mechanical & Manufacturing Engineering 2 RMIT University©2015 
Teaching 
Week 
Lecture Topics Tutorial Topics Assessments/
Tasks 
Week 6 Auxiliary Views 3D modelling 
(emphasise on 
isometric views)
Quiz 2 (labs)
Test 1 (1.5hr)
Saturday, 18th April
10:00-12:30pm
Building 56, level 4 
PC labs
Week 7 Section View 3D modelling 
(emphasise on 
Section views)
Week 8 Dimension & Tolerance Generative Drafting 
Fundamentals 
Week 9 Assembly & Drafting Assembly Design 
workbench 
Teaching Schedule 
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Fighter rig Rotary 
Engine Shaper Tool 
head 
Flash Light Silicon Gun 
GPS holder Plummer block Clamp Jack 
Nail 
Clipper 
Group Projects 
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Scaling Factor 
If the scaling factor for your group sf=1.01, you are to multiple all 
the dimensions in the drawing by 1.01 before you start your project 
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Part Design (6pts): Create a 3D file for the manufactured components (x parts) 
specified in the drawings, integrating your group’s scale factor in the 
dimensions.
Assembly Design (6pts): Assemble the mechanism with your created parts, the 
provided components, and the standard parts from the CATIA catalog. All parts 
listed in the Bill of Material (BOM) must be included in your assembly. 
Design modifications (7pts): In a new assembly, modify the design to make 
easier to use or more ergonomic. The handle would be a good place for 
applying changes for instance to make the gun easier to handle or operate.
Drawings creation (6pts): Generate drawings of your model, based on the 
modified design you have created. You must create one assembly drawing as 
well as one drawing per manufactured part (not standard). You must use the 
RMIT A3 template for your title block.
Tasks Description 
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Group Project 
Report due in Week 12 (Template 
given)−leader to submit e-report. pdf 
and CATIA file online 
Problem 
identification 
Analysis 
Documentation 
Refinement 
Ideation 
Decision process/ 
Design selection 
Implementation 
Generate design idea/
possible solution 
Evaluate the ideas 
against the criteria 
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Problem Identification 
1.  Weakness and prone 
to breaking 
2.  Uncomfortable to use 
3.  Hard to line up where 
hole goes on paper 
Group Project Example 
Identify the Design 
problem 
Generate design idea/
possible solution 
Evaluate the ideas 
against the criteria 
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Extra Tutorial Session 
•  Thursday 
•  3:30-6:00pm
•  Lab 56.4.84
•  Tutor: Inam Ullah
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Objectives 
•  Section views
Concept of section view
Define what is meant by a cutting plane
Type of section views
MIET2012 
Section view 
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Section view 
•  Orthographic views showing all hidden lines may not be clear 
enough to describe an object’s internal details. 
•  This shortcoming can be overcome by imagining that part of the 
object has been cut away and shown in a cross-sectional view. 
This view is called a section view. 
 
http://www.khulsey.com/exploded-illustrations.html http://en.wikipedia.org/wiki/Multiview_orthographic_projection 
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Given 
Necessity of a section view
Finish 
No 
Internal features 
make a view 
difficult to read 
or dimension? 
Orthographic 
projection 
principle 
Yes 
Section 
technique 
Orthographic 
projection 
principle 
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Purposes 
Clarify an internal feature. 
Facilitate dimensioning. 
Example 
Regular 
view 
Section 
view 
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Sectional Drawings
1 2 3 5 64 7 A3
1 2 3 4 5 6 7 8
A
B
C
D
E
F
A
B
C
D
E
F
DESIGNED BY:
Thierry Perret-Ellena
DATE:
2014 Sem 2
QUANTITY:
1 Off
CHECKED BY:
TPE
DATE:
THIRD ANGLE PROJECTION SCALE:
3:5 1/1
SHEET:
DOCUMENT TITLE:GENERAL TOLERANCE
ISO 2768 - mK
LINEAR DIMENSIONS
0.5<t 3 0.1
3<t 6 0.1
6<t 30 0.2
30<t 120 0.3
120<t 400 0.5
ANGULAR DIMENSIONS
t 10 1°
10<t 50 ±30'
50<t 120 ±20'
120<t 400 ±10'
400<t ±5'
This drawing is our property; it can't be reproduced or communicated without our written agreement.
NEXT ASSY:
DRAWING REVISION
DESCRIPTION DATE APPROVAL
01 1
ITEM REF QTY DESCRIPTION MATERIAL/DRAWING NO. REMARKS/SUPPLIER/CATALOG NO.
SIGNATURE:
FINISH:
DOCUMENT TYPE:
Part Drawing
400<t 1000 0.8
1000<t 2000 1.2
(SHARP EDGES BROKEN
(GENERAL TOLERANCE ISO 2768 - mK
DRAWING NUMBER:REVISION:
001
PROJECT:
MIET 2093
Quiz 3c
Q3C-P001
46
13R2x 
7R4x 
123
82
66
5
0
3
1
2 6
2
4
A A
B
B
21
Section view A-A
3 1
1
3
5
0
1 2 x 1.75
C
2
19
36
47
Section view B-B
24
18
12
16
8
50
4
1
2
2
1 .5 45
Detail C
Scale: 3:2
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Isomeric Section View
MIET2012 
Basic components 
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Cutting plane 
Cutting plane is an imaginary plane that cuts through the object.
Location and direction of a cutting plane depend on a hidden feature that 
is needed to be revealed.
A section view is obtained by viewing the object after removed the cover 
up part in the direction normal to the cutting plane.
Cutting 
plane 
Example 
Section view 
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Cutting plane line 
In an orthographic view, a cutting plane is presented as a 
“cutting plane line, CPL” and is drawn in an adjacent view 
of the section view. 
Given Direction 1 Direction 2 Direction 3 
Section 
view 
CPL 
CPL 
Section 
view 
Section 
view 
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Viewing 
direction 
Cutting plane line : Line styles 
The cutting plane line is presented by a chain line. 
Begin and end the line with a short visible line. 
When the line changes its direction, draw a short visible line at 
that corner. 
Draw an arrow at the end of a short visible line, the arrow head is 
pointed to this line in a viewing direction. 
Examples 
1 
2 
3 
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Cutting plane line : Placement 
If the cutting plane line is in the same position as a center line, 
the cutting plane line has precedence. 
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Multiple sectioned views 
Multiple section views can be created on a single multiview drawing 
Each section view is labeled to correspond to its cutting plane lineSchool of Aerospace, Mechanical & Manufacturing Engineering 22 RMIT University©2015 
Class activity 
Do you find something wrong in the following cutting plane lines? 
3 
1 
Yes 
No 
Right! 
Wrong! 
(The arrow on the right side 
 should be pointed downward) 
Yes 
No 
Right! 
Wrong! 
(The arrow head have to 
 touch the short visible line) 
Yes 
No 
Right! 
Wrong! 
(Because the cutting plane line used 
 in this course is a chain line ) 
2 
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Class activity 
Change the following incorrect cutting plane line style to that previously 
suggested. 
1 2 
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Section lining : Purpose 
Section lines or cross-hatch lines are added to a section 
view to indicate surface that are cut by a cutting plane. 
Examples 
Section view 
without section lines 
Section view 
with section lines 
Visible surfaces and edges behind the cutting plane are drawn in a section view. 
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The section lines are different for each type of material. 
Cast iron, 
Malleable iron 
Steel Concrete 
Sand Wood 
Practically, the cast iron symbol is used most often for 
any materials. 
Section lining : Symbol 
Examples 
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The spacing between lines may vary from 1.5 mm for 
small sectioned areas to 3 mm for large sectioned areas. 
Poor practices 
Section lining : Recommended practice 1 
Too dense Too coarse 
Uneven spacing Uneven orientation 
Examples 
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It should not run parallel or perpendicular to contour of the view. 
Section lining : Recommended practice 2 
Poor practices 
Examples 
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Section lining : Special case 
When the sectioned area is large, an outline sectioning 
may be used to save time. 
Example 
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Draw section cutting plane line and outline sectioning. 
Class activity 
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Class activity 
Which one is a good practice in section lining? 
1 2 
MIET2012 
Types of 
section 
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Types of section 
1. Full section 
2. Offset section 
3. Half section 
4. Broken-out section 
5. Revolved section (aligned section) 
6. Removed section (detailed section) 
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A skill requirement 
1. Ability in orthographic visualization 
2. Understanding in a conventional practice 
 for each kind of sections. 
 (You will learn about them from now on.) 
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Conventional practice : Treatment of a hidden line 
Hidden lines are usually omitted within the section lined area. 
Example 
Hidden lines 
are omitted. 
Hidden lines 
present. 
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Full section : Concept & example 
A section view is made by passing the straight cutting 
plane completely through the part. 
Example 
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A closer look 
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Offset section : Concept & example 
A section view is made by passing the bended cutting 
plane completely through the part. 
Example 
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Half section : Concept & example 
A section view is made by passing the cutting plane halfway 
through an object and remove a quarter of it. 
Example 
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Half section : Conventional practice
A center line is used for separating the sectioned half from the 
unsectioned half of the view. 
Hidden line is omitted in unsectioned half of the view. 
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A section view is made by passing the cutting plane normal to the 
viewing direction and removing the portion of an object in front of 
it.
Broken-out section : Concept & example 
Example 
The sectioned and unsectioned 
portions are separated by 
a break line. 
Cutting plane line is not 
necessary. 
Break line is freehand drawn 
as a thin continuous line (4H). 
Conventional practices 
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Revolved section : Concept & example 
A section view is made by revolving the cross-section view 90o 
about a cutting plane line and drawn on the orthographic view. 
Example 
a 
a 
b 
b 
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1. Superimposed to orthographic view. 
Superimposed Break 
2. Break from orthographic view. 
Revolved section : 
Placement of a cross-section view 
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Revolved section : Additional example 
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Summary 
Drafter has several choices of section techniques to reveal an internal 
feature of an object. 
Object having a symmetry, an appropriate choice is such as full 
section or half section. 
Object having several features that do not locate in-line among each 
other, an offset section may be a good choice. 
Broken-out section is usually used when a drafter need to reveal a 
local detail of each feature. 
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Comparison of a different section techniques
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Section view 
•  All visible edges and contours behind the cutting plane should be shown. 
•  Hidden lines should be omitted in section views. 
•  A section view should always be bounded by a visible outline. 
•  There should be no lines in the hatched area. 
•  Section lines should be in the same direction. 
•  Use standard section lines (hatch) to show materials. 
School of Aerospace, Mechanical & Manufacturing Engineering 47 RMIT University©2015 
Sample Exam Question Match&the&section&view&for&the&object&shown&the&pictorial.&&&
Given&
& &
&
&&
&& &
&&
&
&&
&&A& B& C& D&
 
 
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Given
Practice yourself: 
Sketch the necessary section views of the given object 
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Given
Practice yourself: 
Sketch the necessary section views of the given object 
MIET2012 
Threaded Fasteners 
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FASTENING TYPE 
 Threaded fastener 
 - bolts 
 - studs 
 - screws 
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Crest 
Root 
Thread angle 
THREAD TERMINOLOGY 
The peak edge of a thread. 
The bottom of the thread cut into 
a cylindrical body.The angle between threads faces. 
Internal Thread External Thread 
Crest Root 
Thread angle 
Crest Root 
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Major diameter 
The largest diameter on 
an internal or external thread. 
Minor diameter 
The smallest diameter on 
an internal or external thread. 
Internal Thread External Thread 
M
in
or
 d
ia
. 
M
aj
or
 d
ia
. 
THREAD TERMINOLOGY 
M
in
or
 d
ia
. 
M
aj
or
 d
ia
. 
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Pitch The distance between crests of 
threads. 
Lead The distance a screw will advance 
when turned 360o. 
THREAD TERMINOLOGY 
Internal Thread External Thread 
Pitch 
Pitch 
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External thread Internal thread 
DETAILED REPRESENTATION 
60o Pitch 
Use slanting lines to represent crest and root. 
Roots and crest are drawn in sharp Vs. 
Thread runout 
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SIMPLIFIED REPRESENTATION 
External thread Internal thread 
Use thick continuous lines for representing crest 
and thin continuous lines for representing root of 
the thread, respectively. 
Pitch/2 
Root 
Crest 
Thread runout 
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Nominal 
size 
Major 
diameter 
Pitch Minor 
diameter 
Tap drill size 
M6 6.00 1.00 4.92 5.00 
M8 8.00 1.25 6.65 6.75 
M10 10.00 1.50 8.38 8.50 
M12 12.00 1.75 10.11 10.00 
METRIC COARSE THREAD 
Minor diameter = Major diameter – Pitch 
Minor diameter ≈ Tap drill size Metric thread 
In thread drawing, the following relationship is used. 
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DIMENSIONING EXTERNAL THREAD 
M 10 ×1.5 
×1.0 Fine thread 
Coarse thread 
xx 
Thread 
length 
Use local note to specify :- thread form, nominal size, 
pitch (if it is a fine thread) 
Use typical method to specify :- thread length. 
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3. Thread form 
4. Nominal size 
5. Pitch 
1. Tap drill size 
2. Drill depth 
6. Thread depth 
8.50 Drill, 20 Deep, 
M10 Tapped, 15 Deep 
DIMENSIONING THREADED HOLE 
Use local note to 
specify 
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1) Through hole 2) Blinded hole 
φ10 
Hole’s 
depth 
φ 10, 12 Deep 
(or 10 Drill) (or 10 Drill, 12 Deep) 
Symbols for Drilling Operations 
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BOLT : Terminology 
Bolt is a threaded cylinder with a head. 
Hexagonal head 
bolt and nut 
Head 
thickness 
Thread length 
Length 
Width 
across flat 
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CAP SCREW : Counterbore hole 
x drill, 
φ y C’bore, 
z deep 
x drill,w deep, 
φ y C’bore, 
z deep 
z 
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x drill, 
CSK to φy 
CAP SCREW : Countersink hole 
x drill, w deep, 
CSK to φy 
y 
Draw 90o 
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Symbols for Drilling Operations 
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Matric thread note