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Unformatted text preview: Chapter 12
Working Drawing TOPICS
Assembly section Introduction DEFINITION
Working drawing is a set of drawing used
during the work of making a product. Working drawing Detail
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 working positions. PURPOSE
Detail drawing conveys the information
and instructions for manufacturing the part.
Assembly drawing conveys
1. completed shape of the product.
2. overall dimensions.
3. relative position of each part.
4. functional relationship among various
components. Detail Drawing INFORMATION IN
1. General information Title block 2. Part’ s information
2.1 Shape description Object’s 2.2 Size description views 2.3 Specifications Notes GENERAL INFORMATION
Name of company
Title of drawing (usually part’s name)
Drawing sheet number
Name of drafter, checker
Relevant dates of action
(drawn, checked, approved etc.)
Method of projection PART’ S INFORMATION
Shape Orthographic drawing
Pictorial drawing Size Dimensions and Tolerances Specifications Part number, name,
Type of material used
General tolerances RECOMMENDED PRACTICE
Draw one part to one sheet of paper.
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.
Standard parts such as bolt, nut, pin, bearing
do not require detail drawings. PLACING AN INFORMATION Completed dimension
orthographic drawing Part No., Part name, material, Number required
Unit, fillets & rounds sizes etc. Title block EXAMPLE : Interpreting detail drawing 1. Orthographic
Gen. tolerance Projection
Revision table Assembly Drawing TYPES OF ASSEMBLY DRAWING
1. Exploded assembly drawings
The parts are separately display, but they are aligned
according to their assembly positions and sequences. 2. General assembly drawings.
All parts are drawn in their working position. 3. Detail assembly drawings
All parts are drawn in their working position with a
completed dimensions. 1. EXPLODED ASSEMBLY
Finished product 1. EXPLODED ASSEMBLY
Isometric representation 1. EXPLODED ASSEMBLY
Orthographic representation 2. GENERAL ASSEMBLY
Orthographic NO DIMENSION AT ALL 2. GENERAL ASSEMBLY Only dimensions relate to
machine’s operation are
given. Only dimensions relate to
machine’s operation are given
in tabulated form (not shown). 2. GENERAL ASSEMBLY 3. DETAILED ASSEMBLY
(working-drawing assembly) REQUIRED INFORMATION IN
GENERAL ASSEMBLY DRAWING
1. All parts, drawn in their operating position.
2. Part list (or bill of materials, BOM)
1. Item number
2. Descriptive name
3. Material, MATL.
4. Quantity required (per a unit of machine), QTY.
3. Leader lines with balloons around part numbers.
4. Machining and assembly operations and critical
dimensions related to operation of the machine. PLACING AN INFORMATION - Assembled parts
- Reference numbers Part list
Title block PART LIST (BOM)
Locate above or beside the title block.
Fill the table from the bottom. 3 SET SCREW 1 Stainless Steel,
M3 HEX SOCK CUP PT 2 SHAFT 1 Stainless Steel 1 SUPPORT 2 Cast Iron NO. PART NAME REQD. MATL. & NOTE PART LIST (BOM)
Also can be locate at top-right corner.
Fill the table from the top. EXAMPLE : Another allowable place for BOM STEPS TO CREATE
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.
3. Choose major parts, i.e. parts that have
several parts assembled on.
4. Draw a view of major parts according to a
selected viewing direction. STEPS TO CREATE
5. Add detail view of the remaining parts at their
6. Apply section technique where relative
positions between adjacent parts are needed
7. Add balloons, notes and dimensions (if any).
8. Create BOM. GENERAL PRACTICE
The number of views can be one, two, three
or more as needed, but it should be minimum.
A good viewing direction is that represents all
(or most) of the parts assembled in their working
position. EXAMPLE : Selection of a necessary view
Given Part A
Student A Part B
Student B Which is an appropriate view for assembly drawing ? GENERAL PRACTICE
Hidden lines usually omit unless they are
absolutely necessary to illustrate some
important feature that the reader might
otherwise miss. EXAMPLE : Hidden lines omit or not ?
A Part A B C
Part B Good Poor EXAMPLE : Hidden lines omit or not ? A
Part A B Part B Good Poor EXAMPLE : Hidden lines omit or not ?
A Part A B Part B Good Poor GENERAL PRACTICE
Section technique is usually need to clarify
mating of the parts.
Use different section line styles for adjacent parts.
Correct Part A Better
Color OFF ON SECTION LINE PRACTICE
Do not draw section lines on sectional view of
- Threaded fastener
- (longitudinal cut of) Solid shaft, Pin, Key EXAMPLE 1 : Assembly steps 1 CLEVIS, Steel, 1 REQD. 2 ARM, Steel, 1 REQD. 3 PIN, Steel, 1 REQD. EXAMPLE : Section line practice
Which is an appropriate
full section view of this
assembly ? Good Poor Color OFF ON EXAMPLE 2 : Assembly steps 1 SUPPORT, Steel, 1 REQD. 2 SHAFT, Steel, 1 REQD. 3 TAPER PIN, Steel, 1 REQD. EXAMPLE : Section line practice
A Which is an appropriate
full section view of this
assembly ? Good
OFF ON B C D EXAMPLE 3 : Assembly steps 2 ARM, Steel, 1 REQD. 1 CLEVIS, Steel, 1 REQD. 3 PIN, Steel, 1 REQD. EXAMPLE : Section line practice
A B C
Which is an appropriate
section view of the joint ? Good Poor Color OFF ON LEADER LINE PRACTICE
Drawn from the inside of the part to the balloon
and placed a filled circle at the beginning of a line.
Drawn in the oblique direction.
2 EXAMPLE Shaft Bearing
Housing Mating of Parts POINTS TO CONSIDER
1. Surface finishing
- Geometry SURFACE FINISHING
Surface finishing means the quality of a surface.
It relates to the level of roughness of a surface.
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. TOLERANCE
Tolerance is the total amount dimension may vary.
It is defined as the difference between the upper
and lower limits.
1. To control an interchangeability of parts.
2. To ensures the mating part will have a
desired fit. ...
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This note was uploaded on 02/02/2012 for the course DRAW 101 taught by Professor Laosimkim during the Spring '11 term at University of Macau.
- Spring '11