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ES050 – Introductory Engineering
Design and Innovation Studio
Engineering drawings
Prof. Paul Kurowski
January 13, 2010
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Creating drawings
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Creating drawings
pot.SLDPRT
pot.SLDDRW
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Creating drawings
bracket.SLDPRT
bracket.SLDDRW
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Creating drawings
hanger.SLDPRT
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Creating drawings
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Creating drawings
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
Drawings are constructed to strict standards to ensure a consistent
interpretation.

Often are part of a contractual document

Emphasis is on clarity and simplicity.

Generally prefer to use symbols over notes since manufacturer may
not speak English.
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PARTS OF A TYPICAL DETAIL DRAWING
sheet
revision
block
views
title
Block
(TOC)
notes
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DRAWING SHEET SIZES
North America
International
A
8.5”x11”
A4
210mm x 297mm
B
11”x17”
A3
297mm x 420mm
C
17”x22”
A2
420mm x 594mm
D
22”x34”
A1
594mm x 841mm
E
34”x44”
A0
841mm x 1189mm
Choose sheet size such that drawing is filled but not crowded (based on number of
views and dimensions needed).
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DRAWING SCALE

Title block indicates scale which is predominantly used for views on
drawing.

If a view uses a different scale it must be indicated under that view.

Scales are given as whole number ratios


interpret as (drawing unit) : (physical unit)

for scaling up: e.g. 2:1, 4:1, 10:1

for scaling down: e.g. 1:2, 1:5, 1:20

must have a 1 in the ratio. e.g. 2:3 not acceptable
Scale is chosen so that the features can be clearly seen.
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NOTES

Gives useful information not covered by dimensions, symbols or in
the title block.

Can also be used with arrows to indicate features of importance.

Current practice is to limit the use of notes since they may be
misinterpreted.
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DRAWING VIEWS

Only use the number of views necessary to convey information
about the part (an isometric view is the exception)

Often need only two or three views

Edges which are visible in that view are shown as solid lines

Edges which are not visible are called hidden lines

Best not to show hidden lines

you cannot dimension to hidden lines anyway

they reduce clarity in drawings of complex parts
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ORTHOGRAPHIC (PROJECTED) VIEWS

Primary views on a drawing

Set of views at 90° to each other

Created by placing part in a virtual box and look through each side.

True size and shape

angles are correct

circles are round

lengths are to scale
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ORTHOGRAPHIC STANDARD PRACTICE

Choose front view as most descriptive

Determine views to best represent object

Use minimum number of views to completely describe object

Views must be aligned

Views should not be labeled
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AUXILIARY VIEWS

It is an extra view of an object

It is used when the 6 principal views don’t describe an object (or
some of its features) clearly or completely - in particular inclined
features

Should not be labeled

It is used to show the true lengths of lines

It is used to show the true size of planes
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AUXILIARY VIEW
ORTHOGRAPHIC (PROJECTED) VIEWS
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SECTION VIEWS

Useful to show interior features without using hidden lines

Must show section line in another view which indicates the cutting
plane and the direction of view

Does not need to be aligned with parent view but often is shown
aligned to enhance clarity

Must have unique letter label
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SECTION VIEWS
section line
unique view label
cutting plane surface
cross-hatched
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ALLIGNED SECTION VIEWS
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DETAIL VIEWS

Used as enlargement of another view to enhance clarity of small
features

Must show detail area in parent view with label

Is not aligned with parent view

Must have unique letter label and scale must be indicated since it is
different from the parent view
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DETAIL VIEWS
detail
area
with label
detail view with label
and scale
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BREAK VIEWS
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ISOMETRIC VIEW

3D view of part used to help visualization

Common if 3D CAD system used to develop drawing

Used only for a visual reference. Do not dimension this view.

Common now for assembly drawings.
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ISOMETRIC VIEW
Orthographic (projected) views
isometric view
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What type of
view is this?
ES1050 PART 01.sldprt
The view indicated by the callout is:
A
Projected
B
Auxiliary
C
Section
D
Aligned section
E
Detail
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What type of
view is this?
ES1050 PART 01.sldprt
The view indicated by the callout is:
A
Projected
B
Auxiliary
C
Section
D
Aligned section
E
Detail
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What type of
view is this?
flange.sldprt
The view indicated by the callout is
A
Section
B
Aligned section
C
Detail
D
Broken out section
E
Break
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What type of
view is this?
flange.sldprt
The view indicated by the callout is:
A
Projected
B
Auxiliary
C
Section
D
Aligned section
E
Detail
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What type of
view is this?
flange long.sldprt
The view indicated by the callout is
A
Projected
B
Section
C
Detail
D
Broken out section
E
Break
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CENTRE LINES
Used to indicate centres of full circles and axis of cylindrical features
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ASSEMBLY DRAWINGS

Assembly drawings show all the parts and how they go together.

Dimensions are not usually required.

A parts list or Bill of Material (BOM) specifies the item, quantity,
description, part number, etc. for each part.

The item numbers from the parts list for each part are indicated
using numbered balloons in the view.

Common styles used for assembly drawings:


as assembled view

section view

exploded view - Preferred!
Notes are used for assembly and machining instructions
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ASSEMBLY DRAWING AS ASSEMBLED
BOM
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ASSEMBLY DRAWING SECTION VIEW
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ASSEMBLY DRAWING EXPLODED VIEW
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DIMENSIONING OUTLINE

General Rules

Linear Dimensions

Angular Dimensions

Radial Dimensions

Diameter Dimensions

Holes

Tolerances
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INTRODUCTION

Dimensions give size, location and details of all features of the part.

Manufacturing method is not specified but driven by dimensions,
material and tolerances.

Dimensions are used per a standard to ensure consistent
interpretation and clarity

Dimension standard often indicated on drawing in title block.
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GENERAL RULES

Text height for dimensions and notes typically either .12” or 3 mm.

Text is always uppercase.

Units are usually either inches or millimetres.

If using inches:


no zero precedes decimal (.250)

dimensions expressed to same number of decimals as its tolerance
(.250±.002)
If using millimetres:

zero precedes the decimal (0.5)

no trailing zeros are required (2±0.5, 3.25±0.1)

Dimension text is always horizontal.

Do not dimension to hidden lines.
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LINEAR DIMENSIONS
dimension
line
visible gap
extension
line
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DIMENSION PLACEMENT


Dimensions are placed outside the part.
Do not crowd dimensions and avoid crossing dimension lines with
extension lines.
space
space
aligned
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ANGULAR DIMENSIONS
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RADIAL DIMENSIONS


Small radii are called fillets.
Preference is to use unlocated centres (easier to measure)
Unlocated Centre
Located Centre
radius
symbol
leader line
centre
mark
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RADIAL DIMENSIONS

Never dimension to radii tangent points.
Tangent point
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DIAMETER DIMENSIONS
large diameter
diameter
symbol
centreline
small diameters
(arrows don’t fit inside)
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HOLE DIMENSIONS

Multiple holes are common on parts so standardized symbols have
been adopted.
Thru Hole
Blind Drilled Hole
depth
symbol
depth of full
diameter
note drill
point
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COUNTERBORED HOLES
Thru Hole
Blind Hole
counterbore
diameter & depth
counterbore
symbol
Note: depths always
measured from top surface
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DIMENSIONING TECHNIQUES

Must give position and size of each feature but only once on the
drawing.

do not dimension the same feature again in a different view
unless dimension for reference only

Dimension based on the function of the feature.

Dimension to reduce tolerance stack-up for critical features.

Always dimension position of holes to their centre not their edge.

Tolerance scheme in the solid model may not be suitable for the
drawing.
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OVER DIMENSIONED
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REPEATED FEATURES
Repeat symbol
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WHAT IS WRONG?
lever.sldprt
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WHAT IS WRONG?
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WHAT IS WRONG?
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WHAT IS WRONG?
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WHAT IS WRONG?
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WHAT IS WRONG?
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WHAT IS WRONG?
flange.sldprt
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WHAT IS WRONG?
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WHAT IS WRONG?
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