Introduction to Engineering
Drawings
By: Chris Vandelaar
University Machine Services
TEB Rm. 50
Resources:
Doug Phillips – Previous MME259A presentation
Interpreting Engineering Drawings
3rd edition by Jensen & Hines
Engineering Drawings:
The language of manufacturing
How we communicate our intentions as
designers
Convey all necessary information to get
things made, manufactured, modified,
assembled
Engineering Drawings:
Can be quite simple
Hydraulic Piston - Simple Part?
Engineering Drawings:
Can be complex
Engineering Drawings:
Contain only pertinent information
To ensure all engineering specifications and
requirements are met
What is pertinent
•
•
•
•
Form – shape of the part
Geometry – acceptable deviation from form
Dimensions – sizes of forms and shapes
Tolerances – acceptable deviation from
dimensions
• Surface finish and or treatment
• Other General information - notes
Pertinent information???
Form:
Shown with pictures
Orthographic projection
Orthographic views
This shows: Third Angle
Projection
Projection Standard is communicated by
Simple Projection Symbols
First Angle Projection: ISO/Europe
• Like rolling the part on a table
Third Angle Projection: North America
• Like walking around the part
Projection Symbols:
The very first thing a manufacturer looks for.
EXTREMELY IMPORTANT!
Orthographic Views
Sometimes can’t show everything
Additional Views may be required
Additional Views Include:
• Section Views
• Cut-away Views
• Broken Views
• Revolved Section Views
Not as common
Section view – shows part form along
specified line(s) – “SECTION LINE” (dashed)
Cut-away View
– shows part form behind front face
Break Views:
• Allow use of larger scale for larger parts
– Smaller drawings
Break View – for long parts
Break Lines
Shorten views to
better fit the page
Notice Important Features of Break View:
•Instance numbers-Indicate number of spaces and holes
•Break line in overall length dimension – Indicates the presence
of a break view
Revolved Section Views – Show
profile forms
Difficult to do
using solidworks
Not very common
these days
Engineering Drawings:
Contain only pertinent information
Pictures
Orthographic and alternate views
Lines – Different lines mean different things
Line Types
• Object Lines – Show Part Geometry or Form
– Visible – (Solid Lines)
• Illustrate external features and outlines
• As if looking at the part
– Hidden – (Dashed Lines)
• Illustrate anything behind the front face of the view
• As if looking through the part
– Phantom –
• Show non existent/alternate parts or features
Object and Hidden Lines
Phantom Lines:
Line Types
• Object Lines – Show Part Geometry or Form
– Visible – (Solid Lines)
– Hidden – (Dashed Lines)
– Phantom – (Dotted or short /long dash lines)
• Reference Lines – Show references
– Center Lines – Long/short dash (alternating)
– Section Lines – indicate views (short dash)
Reference Lines:
Line Types: Review
Engineering Drawings:
Pertinent information
Pictures
Orthographic views
Lines – Different types
Dimensions – Show feature sizes
Dimension Types:
Standard - incremental
Base Line – absolute
Ordinate – absolute
Incremental: point to point – one position to
the next
Absolute: reference one single point
(DATUM)
Dimension Types: ANSI Standards shown
Standard
Incremental
Ordinate
Absolute
Baseline Ordinate
Absolute
Other Dimensioning:
Simple holes
(mm)
More complex holes
(SAE – Inches)
Other Dimensioning:
Engineering Drawings:
Pertinent information
Pictures
Orthographic and alternate views
Lines – Different types
Dimensions – Show feature sizes
Tolerances – Allowable deviation from size
Tolerance Types:
• Basic – standard tolerance from title block
• Bilateral – shows allowable deviation from nominal –
above or below
• Limit – gives two dimensions – anything in between
accepted
• Symmetric – gives one tolerance – above or below
nominal
• Min/Max – anything over or under
• Fits – alone, with, or without tolerance
– References standard Engineering fits
Standard Fits:
Engineering Drawings:
Pertinent information
Pictures
Orthographic and alternate views
Lines – Different types
Dimensions – Show feature sizes
Geometric Dimensioning and tolerancing – (GD&T)
Geometric Dimensioning and
Tolerancing:
GD&T
• The allowable deviation from
nominal form
GD&T Uses:
1. Datum – point of reference
– Face, Edge or Hole
2. Symbol – type of deviation
3. Tolerance – allowable variation
– Given as distance
Example of Geometric tolerance:
Example of Geometric tolerance: Labelled
GD&T uses symbols to communicate geometric specifications
Which area of this block is
out of tolerance?
GD&T is the only way to
guarantee correct form
Dimensions only guarantee
size
Drawing views:
Contain some or all of the following:
1. Dimensions
2. Tolerances
3. Geometric Tolerancing
4. Surface finish information
5. Allowable tool mark information
Drawings Contain:
1. Drawing Templates or Borders
2. Drawing Views
3. Title Block
4. Revision Block
5. Notes – special or standard
Title Blocks:
Can vary in:
– Size
– Content
– Location
TITLE BLOCKS :
Contain any information that cannot be
communicated through orthographic views and
dimensions.
Examples: (not limited)
•Part materials
•Part quantities
•Authors – supervisors – inspectors
•Inspection information/standard
•Finishing info – Painting, anodizing, heat treating
•Customer info
•Company Info
Special Notes:
•Can be located anywhere on the drawing – In title block or specific views.
•Some times drawing views have notes that simply say, “SEE NOTE #”
referring to standard notes in the notes field.
Examples:
1. See Note #? (in drawing pain)
2. Supplier info (notes field)
3. Clearance hole only (in drawing pain view attached to dimension)
4. Remove all sharp edges unless specified (Notes field)
5. Part to be painted as per manufacturers instruction and specification
(notes field)
6. Surface treatments as per ASTM standard “- - - -“ (notes field)
7. Any information at all required to achieve design intention.
FOR NON-STANDARD INFORMATION
THE END
Introduction to Engineering
Drawings
By: Chris Vandelaar
University Machine Services
TEB Rm. 50
Resources:
Doug Phillips – Previous MME259A presentation
Interpreting Engineering Drawings
3rd edition by Jensen & Hines