This document provides an overview of engineering drawings, including their purpose and different types. It discusses the main reasons drawings are used in industry which are for communication, discussion, and record keeping. It also describes the different types of engineering drawings including assembly drawings, sub-assembly drawings, detail assembly drawings, and detail drawings. Finally, it discusses how drawings are produced and standards that drawings should follow.

1. ENGINEERING DRAWING
By
Norazlina bt Abdul Nasir

2. CHAPTER 1 - OVERVIEW OF ENGINEERING
DRAWING
A. The Purpose of Drawing in Industry
A. Types and Functions of Engineering Drawings
i. assembly
ii. sub-assembly
iii. detail assembly
iv. Detail
B. Producing Drawings

3. OVERVIEW OF ENGINEERING DRAWING
i. The Purpose of Drawing in Industry
 There are three main reasons for drawing in industry.
a. Communication
 Engineering drawing is the main method of communication between all
people concerned with the design and manufacture of components,
building and constructions, and engineering projects.
b. Discussion
 Drawings are very useful for developing ideas and theories and
discussing them with colleagues. For instance a manufacturer might
discuss the problems of a manufacturing process with an engineer.
c. Records
 Drawings are kept for:
1. Extra orders of components.
2. Recording previous specifications.
3. Records of current job specifications in case of faulty manufacture
or design.

4. TYPES AND FUNCTIONS OF ENGINEERING
DRAWINGS
 The basic engineering drawings are:
i. assembly
ii. sub-assembly
iii. detail assembly
iv. detail.
 Assembly drawings
 Assembly drawings show a general overview of the
completed job, with arrangements of parts and a list of
parts. They are sometimes called general assemblies.
They only show overall dimensions.

5.  Sub-assembly drawings
 Sub-assembly drawings only show the arrangement of a
particular part, or a few parts, of the general assembly.
Again, they do not show any fabrication details. Sub-assembly
drawings show how a part of the job is
assembled, not fabricated.
 Detail assembly drawings
 Detail assembly drawings show how the job is
assembled, together with all the details you need to
manufacture it.

6.  Detail drawings
 Detail drawings show all the details you need to do the
job. They generally only show a part of the job, and do
not show the complete assembly of the finished product

7. PRODUCING DRAWINGS
 Drawings are done on standard size sheets, ranging
from AO to A4.
 Methods of production
 Drawings may be made in three ways:
 freehand sketching
 by hand using drafting equipment
 computer assisted (Computer Aided Design - CAD).
 Copying or Reproducing Drawings
 Depending on the size, drawings may be reproduced by:
 photocopying
 dyeline reproduction
 computer plotting

10.  Standards
 Engineering drawings and other technical drawings
have to be done in ways that all engineers can
recognize. These ways are called standards or
conventions.
 Drawings are made to standard conventions so
that:
 they all use the same symbols, lines, dimensioning
techniques etc
 they can be understood in different places, eg interstate
or internationally.

11.  Although there are several drawing standards
available both nationally and internationally, for this
competency all our drawings should follow the rules
of:
 The Australian Standard 1100 - Drawing practice
 The Australian Standard 1101 - Graphic symbols for
electro technology
 Australian Standard is usually shortened to AS. The
drawings in this competency are on standard size
sheets, as stated in AS 1100.

12.  Features
 There are some features, which should appear on every
drawing:
 The title panel should contain the following:
 company name
 drawing name
 drawing number
 date.

13.  Depending on the type of drawing the title panel
may also include:
1. material list
2. revision panel
3. draftsman's name
4. original drawing size
5. scale of the drawing
6. general tolerances
7. projection symbol
8. drafting standard
9. surface finish
10. border.

14.  The border is important because no information
should lie outside it. If we have a copy of the
drawing and the border is complete, we can be
absolutely sure that we have all the information
contained on the drawing.
 Other useful items, which may appear near the
border, are:
 grid referencing
 camera alignment marks
 fold lines.

16.  Classification of Drawings
 As we mentioned before, our drawings can range from
the very simple, to the extremely complex - from a gee-clamp
to an aircraft carrier.
 There is a need then to classify our drawings according
to the function, which they serve.

17.  Assembly Drawings
 An Assembly Drawing may also be called an
Arrangement Drawing, General Arrangement Drawing or
General Assembly Drawing.
 The Assembly Drawing shows a general view of the
completed job, with the arrangement of the parts and
also a parts list. They show overall dimensions but do
not show any manufacturing information.
 The assembly drawing shows how the parts of the “Tee
Wrench” fit together.

20.  Sub-Assembly Drawings
 These drawings show the arrangement of a few parts of
the general assembly. Sub-assembly drawings are
referenced back to an assembly drawing, and are used
so that assembly drawings do not become
unnecessarily complicated.
 As in the assembly drawing, there is no manufacturing
information on a sub- assembly drawing, only assembly
information.
 An example of a Sub-Assembly drawing for Exhaust
Duct - Fan Support Assembly

22.  Detail Assembly Drawings
 These drawings show how the parts fit together and
information necessary to manufacture the parts.
 Detail assembly drawings are used when both the parts
and the assembling of them are simple, and separate
assembly and detail drawings are not justified.
 The detail assembly drawing, Al - 428958 - 003 – AA
(Vulcanising Clamp) shows the assembled parts, how
they are assembled and also the sizes of each of the
components.
 It is different to the sub-assembly drawing, because the
detail assembly drawing has manufactured information
on it.

24.  Detail Drawings
 Detail drawings show all the information you need to
manufacture the part and nothing else at all. The part
may end up in a car, or a gantry crane, or a ship. The
information relating to where the part fits is to be found
on the sub-assembly or assembly drawing.
 An example of a detail drawing is the Fixed Jaw
drawing

26.  Diagrams
 Most of the drawings that a mechanical tradesperson
would use on the job are a ‘pictorial representation’.
This is the type of drawing which shows the object as it
is.
 Another type of drawing, which we may have to use, is
the ‘diagram’. Diagrams usually consist of symbols
connected by lines.
 In electrical diagrams the symbols represent electrical
components and the lines represent the conductors or
wires.
 In hydraulic and pneumatic diagrams the symbols
represent the fittings and the lines represent the piping.

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