Week 9_MIET2093_Assemblies and Technical Drawing

Prévia do material em texto

MIET2012 
1 
Lecture 9: Assembly modelling & Working 
Drawings 
MIET2093 
Computer Aided Design 
 
by: 
Dr. Toh Yen Pang 
tohyen.pang@rmit.edu.au 
9925 6128 
B251.3.22 
Teaching 
Week 
Lecture Topics Tutorial Topics Assessments/
Tasks 
Week 7 Section View 3D modelling 
(emphasise on 
Section views)
Week 8 Dimension & Tolerance Generative Drafting 
Fundamentals 
Week 9 Assembly & Drafting Assembly Design 
workbench 
Week 10 Reverse Engineering 3D scanning (AMP 
building 55, level 4) 
Quiz 3 
Week 11 Rapid Prototyping 3D printing (AMP 
building 55, level 4) 
Week 12 Revision Quiz 4 Quiz 4 
Teaching Schedule 
School of Aerospace, Mechanical & Manufacturing Engineering 3 RMIT University©2015 
AMP (Week 10 – Week 11) 
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School of Aerospace, Mechanical & Manufacturing Engineering 5 RMIT University©2015 
Written Report 
Introduction 
Report due in Week 12 (Template given)−leader 
to submit e-report. pdf and CATIA files online 
 Results 
Methodology 
Contents: 
 Discussion 
 Conclusions 
Abstract 
School of Aerospace, Mechanical & Manufacturing Engineering 6 RMIT University©2015 
Abstract 
Does it reflect the content of the article?
 ABSTRACT: The purpose of this report is to document the process of modelling a Boeing 737-800 
aircraft; involving the use of CAD (Computer Aided Design) software and rapid prototyping 
technologies. The project was to be completed using solid modelling techniques in a group consisting 
of 5 members. 2-D drawings of a base model were provided to the group, along with a scaling factor.���
Solid modelling CAD software (CATIA V5R21) was used to create the model on a computer, before 
being transferred to a 3D printer which provided the final physical model. The creation process 
involved analysing the given drawings, altering the dimensions with the scaling factor, breaking them 
in to their separate parts, and converting them in to a 3D representation on CATIA. ���
The aircraft model was broken up in to 8 parts: cockpit, fuselage, wing, engine, horizontal stabiliser, 
vertical stabiliser, base stand, and base pedestal. The creation of the fuselage model can be broken 
down into basic steps: (1) Formation of the base fuselage body, (2) Rudimentary sketch and pad of the 
fairing, (3) Variable edge filleting of the base fairing, connecting the fairing to the fuselage body, (4) 
Pocket on top of base fuselage housing the vertical stabilizer, (5) Generation of pockets and holes for 
the tabs. Holes: Cockpit; Pockets: Wings, horizontal and vertical stabilisers. (5) Dressing of product.
A final model was created which accurately reflects the base model and a simplified full scale Boeing 
737-800 aircraft. The process showed that using CAD software such as CATIA in conjunction with 
rapid prototyping tools (3D printing) is a successful method for modelling. Model creation is 
important to prototyping and design analysis in the engineering design process. The successful result 
of this project shows that CAD software can play a key role in these design areas.
Objective 
Method 
Literature 
Results 
Discussion 
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Introduction 
•  Does it describe what the author hoped to achieve accurately, 
and clearly state the problem being investigated? 
•  Normally, the introduction should summarize relevant research 
to provide context 
•  It should describe the experiment, the hypothesis(es) and the 
general design or method. 
Identify the Design 
problem 
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Method (1/2) 
•  Does the author accurately explain how the design/development/
process was conducted? 
•  Is there sufficient information present for you to replicate the 
research? 
•  Are these ordered in a meaningful way? 
Generate design idea/
possible solution 
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Method (2/2) 
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Results (1/2) 
•  This is where the author(s) should explain in words whether the 
ideas/concept meet the design criteria 
•  Report the result or design 
•  Are the tables and figures clear and succinct? 
•  Can they be "read" easily for major findings by themselves, or 
should there be additional information provided? 
Comments 
1. Need for explanation or ‘tell a story’ 
2. Label and refer all the figures and tables in text 
Document the solution 
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Results Examples 
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Results (2/2) 
•  There are no holes on the top and the holes are parallel 
to the ground to limit the direct sunlight. 
•  The geometry is done so each air inlet increases the 
airflow from the other inlet, the surrounding air is drawn 
into the airflow. 
Evaluate the ideas 
against the criteria 
School of Aerospace, Mechanical & Manufacturing Engineering 13 RMIT University©2015 
Discussion 
•  The main purpose of the discussion is to show that the results 
lead clearly to the conclusion being drawn
•  Explain the results
•  State the Major Improvement/Modification of the design
•  Include research from previous studies-whether it supports your 
findings/design or not
•  Do the authors thoughtfully address the limitations of their design 
work?
•  Make suggestions for further Research or Design
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Appendix 
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Objectives 
•  Define working drawing 
•  Major components of a complete set of working drawings 
•  Detail and Assembly drawings 
School of Aerospace, Mechanical & Manufacturing Engineering 16 RMIT University©2015 
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:
QUANTITY:
1 Off
CHECKED BY:
TPE
DATE:
THIRD ANGLE PROJECTION SCALE:
3:4 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 Round Bar SAE steel 1045
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
DRAWING NUMBER:REVISION:
001
PROJECT:
Planetary Gearbox
(SHARP EDGES BROKEN
(GENERAL TOLERANCE ISO 2768 - mK
(NOT FOR MANUFACTURE (EDUCATIONAL ONLY)
Shaft Output
SO-P001 GS-A001
2013-05-02
45
8x 
188x 
118x 
106 PCD
Front view
Scale: 3:4
A
A
Section View A-A
Scale: 3:4
1
3
0
±
0
.
1
9
0
6
2
±
0
.
5
7
2
±
0
.
1
5
0
±
0
.
2
1 5
1220
42.6 ±0.125.15
4
7
.
3
2
3
.
6
5
7
0
1 51.65 +0.1-0.3
B
60
12.7
2
4
.
1
5
4
.
5
4
5
Bottom view
Scale: 3:4
6
9
.
2
5
+
0
.
1
-
0
.
3
1 6
15R
14
Detail B
Scale: 3:2
Working Drawing 
School of Aerospace, Mechanical & Manufacturing Engineering 17RMIT University©2015 
Part Drawing 
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Assembly Drawing 
MIET2012 
Assembly Modeling 
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Introduction 
Assembly modeling enable the operator to combine 
components to create a 3D parametric assembly model. 
Assemblies, when brought in as components, are now 
considered subassemblies in the new larger assembly.
School of Aerospace, Mechanical & Manufacturing Engineering 21 RMIT University©2015 
Create an assembly 
Any assembly can be thought of as a hierarchy of 
subassemblies and/or parts and can be represented in a tree 
structure.
Construction an assembly begin with selecting a base 
component because of its central role in defining the overall 
assembly.
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Shaft 
Housing 
Bearing 
Cover 
plate 
Cap 
screw 
EXAMPLE 
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Manipulate the position 
Each successive component brought in needs to be oriented 
and located relative to other components in the assembly
Coordinate systems, both global and local, can also be used to 
orient and locate components
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EXAMPLE 1 : Assembly steps 
3 PIN, Steel, 1 REQD. 
2 ARM, Steel, 1 REQD. 
1 CLEVIS, Steel, 1 REQD. 
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Geometric relations: Mating part
Mate: Two part surfaces/construction planes are set coplanar 
with the directional vectors opposing each other
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Align: Two part surfaces/construction plane are set coplanar 
with the directional vector pointing in the same direction. 
Alternatively, two edges/construction axes are set colinear.
Geometric relations: Align
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Geometric relation 
Parallelism
Tangency
Surface intersecting
Tangency
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Degree of freedom 
Once components are inserted into the assembly, they can be 
manipulated by using the compass to pan and rotate the entire 
assembly, or by freely dragging and rotating components in it. 
School of Aerospace, Mechanical & Manufacturing Engineering 29 RMIT University©2015 
Parent-Child relationship 
When assemble two or more parts with geometry relation, we 
create parent-child relationships between the existing 
components and the new components coming in. 
School of Aerospace, Mechanical & Manufacturing Engineering 30 RMIT University©2015 
Product Structure Reordering 
You can reorder components in the specification tree to meet 
your needs. 
MIET2012 
Introduction to working 
drawings 
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Drawing Sheet 
http://en.wikipedia.org/wiki/Engineering_drawing 
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Definition (1/3)
Working drawing is a set of specialized engineering 
drawing specifying the manufacture and assembly of a 
product based on its design. 
Working drawing
Detail
drawing
Assembly
drawing
School of Aerospace, Mechanical & Manufacturing Engineering 34 RMIT University©2015 
Definition (2/2) 
Detail drawing is a multiview representation of a 
single part with dimensions and notes. 
Assembly drawing is a drawing of various
parts of a machine or structure assembled in their 
relative operating positions.
School of Aerospace, Mechanical & Manufacturing Engineering 35 RMIT University©2015 
Detail drawing 
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Assembly drawing 
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Detail drawing conveys the information and 
instructions for manufacturing the part.
4. functional relationship among various ���
 components.
1. completed shape of the product.
2. overall dimensions.
Purpose
Assembly drawing conveys
3. relative position of each part.
MIET2012 
Detail Drawings 
School of Aerospace, Mechanical & Manufacturing Engineering 39 RMIT University©2015 
Information in Detail Drawing
2.1 Shape description 
2.2 Size description 
2.3 Specifications 
1. General information 
2. Part’ s information 
Title block 
Object’s 
views 
Notes 
3. Dimensions and Tolerance 
4. Material designation 
School of Aerospace, Mechanical & Manufacturing Engineering 40 RMIT University©2015 
General Information in Title block
Ø  Name of company
Ø  Title of drawing (usually part’s name)
Ø  Drawing sheet number
Ø  Name of drafter, checker
Ø  Relevant dates of action���
 (drawn, checked, approved etc.)
Ø  Revision table
Ø  Unit
Ø  Scale
Ø  Method of projection
School of Aerospace, Mechanical & Manufacturing Engineering 41 RMIT University©2015 
Drawing Template 
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:
...
DATE:
...
QUANTITY:
1 Off
CHECKED BY:
TPE
DATE:
THIRD ANGLE PROJECTION SCALE:
1:1 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:
...
School of Aerospace, Mechanical & Manufacturing Engineering 42 RMIT University©2015 
Part list Information
v  Orthographic drawing
v  Pictorial drawing
v  Dimensions and Tolerances
Specifications
v  General notes
v  Type of material used
v  Surface finish
v  General tolerances
v  Part number, name,���
 number required
Shape
Size
v  Heat treatment
School of Aerospace, Mechanical & Manufacturing Engineering 43 RMIT University©2015 
If not the case, 
- apply enough spacing between parts.
- draw all parts using the same scale.
 Otherwise, the scale should be clearly note���
 under each part’s drawing.
Draw one part to one sheet of paper.
Recommended Practice
Standard parts such as bolt, nut, pin, bearing
do not require detail drawings.
School of Aerospace, Mechanical & Manufacturing Engineering 44 RMIT University©2015 
Placing an Information
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
Bracket
MIET 2093 Class Test
DESIGNED BY:
Thierry Perret-Ellena
DATE:
2014-04-07
QUANTITY:
1 Off
CHECKED BY:
TPE
DATE:
THIRD ANGLE PROJECTION SCALE:
1:1 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:
SIGNATURE:
FINISH:
DOCUMENT TYPE:
Part Drawing
400<t 1000 0.8
1000<t 2000 1.2
DRAWING NUMBER:
BR-P001
REVISION:
001
PROJECT:
MIET 2093
3
6
75
26R
28 THRU ALL
6
3
1
7
.
5
125
107
2
2
1
3
1 8R 18 THRU ALL
75R
12 x1.75 THRU
5R4x 
28
3R2x 
23
4
4
5
2
x
 
6 0 30
1
7
2
2
2xR THRU
7R2x 
2R2x 
5
2
2
2
5
3 6
4
9
30
52x 
2
4
5
2
4
5
3
2 3
Isometric view
Scale: 1:2
School of Aerospace, Mechanical & Manufacturing Engineering 45 RMIT University©2015 
EXAMPLE : Interpreting detail drawing 
General note 
Title block 
1. Orthographic 
 views 
2. Dimensions 
 & Tolerances 
3. Surface 
 finishing 
Projection Gen. tolerance 
MIET2012 
Assembly Drawings 
School of Aerospace, Mechanical & Manufacturing Engineering 47 RMIT University©2015 
Purpose of Assembly Drawing
The main purpose of an assembly drawing is to give a big picture view of 
the completed project and show all of the different parts in the assembly, 
and how these parts fit together to create the mechanism or product. 
http://solidworksautocad.wordpress.com/2011/06/20/assembly-montaj/ 
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1. Exploded assembly drawings 
3. Detail assembly drawings 
Types of assembly drawing
2. General assembly drawings 
The parts are separately display, but they are aligned 
according to their assembly positions and sequences. 
All parts are drawn in their working position. 
All parts are drawn in their working position with a 
completed dimensions. 
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1. Exploded Assembly (1/2)
Pictorial representation 
Finished product 
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Orthographic representation 
1. Exploded Assembly (2/2)
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2. General Assembly (1/2)
Pictorial Orthographic 
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Only dimensions relate to machine’s operation are given.
2. General Assembly (1/2)
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2. GENERAL ASSEMBLY 
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3. DETAILED ASSEMBLY
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1. All parts, drawn in their operating position.
2. Part list (or bill of materials, BOM)
3. Leader lines with balloons around part numbers.
1.  Item number
2.  Descriptive name
3.  Material, MATL.
4.  Quantity required (per a unit of machine), QTY.
4. Machining and assembly operations and critical���
 dimensions related to operation of the machine.
Required Information In
General Assembly Drawing
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Part List (BOM) 
NO. PART NAME REQD. MATL. & NOTE 
1 SUPPORT 2 Cast Iron 
2 SHAFT 1 Stainless Steel 
3 SET SCREW 1 Stainless Steel, M3 HEX SOCK CUP PT 
Locate above or beside the title block. 
Fill the table from the bottom. 
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EXAMPLE : Another allowable place for BOM 
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Steps to Create Assembly Drawing (1/2)
4. Draw a view of major parts according to a 
 selected viewing direction.
3. Choose major parts, i.e. parts that have
 several parts assembled on.
1. Analyze geometry and dimensions of all parts ���
 in order to understand the assembly steps and���
 overall shape of device or machine.
2. Select an appropriate view.
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6. Apply section technique where relative
 positions between adjacent parts are needed
 to clarify.
7. Add balloons, notes and dimensions (if any).
5. Add detail view of the remaining parts at their
 working positions. 
8. Create BOM.
Steps to Create Assembly Drawing (2/2)
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A design which depicts multiples parts which are part 
of a larger assembly. 
 
Sub-Assembly Drawing
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1. Surface finishing 
2. Tolerance 
 - Size 
 - Geometry 
POINTS TO CONSIDER 
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SURFACE FINISHING
1. To control the accuracy in positioning and ���
 tightness between mating parts.
2. To reduce the friction, especially for the part ���
 moves relative to other parts.
Surface finishing means the quality of a surface. It 
relates to the level of roughness of a surface.
Purpose
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Tolerance is the total amount dimension may vary.
It is defined as the difference between the upper and 
lower limits.
TOLERANCE
Purpose
1. To control an interchangeability of parts.
2. To ensures the mating part will have a���
 desired fit.
MIET2012 
Tolerance
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Tolerance is the total amount dimension may vary. 
It is defined as the difference between the upper 
and lower limits. 
TOLERANCE
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TOLERANCE: Purpose
1. To control an interchangeability of parts. 
2. To ensures the mating part will have a 
 desired fit. 
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TOLERANCE Representation
Tolerance can be expressed in several ways: 
Direct limit or as tolerance values applied directly 
to a dimension
Geometric tolerances
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Plus & Minus Tolerance
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Fit
The degree of tightness between mating parts is called the fit. 
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Fit Type Determination
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Summary 
•  Working drawings are a fundamental part of any manufacturing or 
construction business. 
•  Assembly models and drawings 
•  Components of drawings 
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Practice Questions 
•  Define working drawings. 
•  List the types of drawings commonly found in a complete set of 
working drawings. 
•  List the important items in a title block.