1. Unit 1 Bases for Blueprint Reading and Sketching
Part 1-Section 1 Lines
Unit 1
Bases for Blueprint Reading and Sketching

2. Introduction Technical information through spoken or written word
Shape, construction, simple geometries
Methods of drawings
Picture or photography
Computer or technical sketch
More accurate and detailed information provided

3. Blueprint Reading as a Universal Language
Blueprints
Furnish information about an object to all groups involved in a project
Process of drawing interpretation
Accurate mental picture of finished object
Training includes:
Development of visual ability
Dimension application

4. Standards Governing the Preparation of Drawings
Universally adopted:
Standards
Symbols
Technical data
Principles of graphic representation
Blueprints may be uniformly interpreted throughout world

5. Standards-Setting Organizations
American National Standards Institute
International Organization for Standardization
Incorporate and complement standards developed and accepted by:
American Society of Mechanical Engineers, American Welding Society, and American Institute for Architects

6. Standards for Sheets
Published by ASME for sheets onto which blueprints are made

7. Common Elements in Drafting
Lines
Provide graphic information about object external shape and details
Dimensions
Give size and location of parts, shapes, and assemblies

8. Common Elements in Drafting (cont’d.)
Sections
Expose internal construction details when an object is cut apart by imaginary cutting planes.
Processes
Represented by symbols and notes for purposes of identifying how each part is to be produced

9. Common Elements in Drafting (cont’d.)
Geometric positioning
Deals with placing and accuracy of geometric objects in relationship to one another
Notes
Non-graphical information clearly lettered (printed)

10. Common Elements in Drafting (cont’d.)
Tolerances
Deal with accuracy related to form and size and position of finished surfaces, where high precision is required
Materials used for making parts
Includes information about weight, strength, and hardness

11. Common Elements in Drafting (cont’d.)
Computer-aided drafting (CAD) applications
Technical sketching techniques
Prepare line and form engineering and technical sketches

12. Industrial Practices Relating to Drawings
Blueprint
Traditionally produced by exposing drawing to strong light source
Originally referred to blue and white reproduction of drawing
Today, includes any type of technically reproduced drawing

14. Drawing Reproduction Processes
Highest quality reproductions made by plotters:
Flatbed plotter
Drum plotter
Multigrip plotter
Other reproduction methods:
Printers, diazo, copy machines, scanners

15. Drawing Storage Procedures
Microfilm
Flat-drawer files
Files designed for vertical hanging
Tubes
Electronic storage

16. Hardcopy and Softcopy Drawings
Drawing sheet
Permanent copy of a drawing
Produced on conventional blueprinting equipment or computer-generated
Softcopy
Drawings as they appear on computer screens

17. CAD/CAM CAM: computer-aided manufacturing
Drafting department designs product on computer
Drawing converted to coordinate data and stored
Post processor
Converts stored coordinate data into usable format for manufacturing machines

18. Some Technical Information Supplied on Drawings
Title block contains:
Name of the part (guide pin)
Quantity needed
Drawing number
Dimensional tolerance
Material

20. Universal Systems of Measurement
Linear or straight line
Most widely used measurements between two points, lines, or surfaces
Begins at reference point; ends at measured point
Line of measurement (basic size)
Straight line distance between two points
Represents actual required dimension

21. Universal Systems of Measurement (cont’d.)
Basic units of linear measurement
Dimensions are in one or combination of two units of measurement
Inch and metric units
Dimensions given as fractional parts of inch or decimal inch values
Inch subdivided into equal parts called fractional parts or decimal (mils) parts

23. Universal Systems of Measurement (cont’d.)
Metric linear units of measurement
Generally given in millimeters
Common steel rules graduated in whole and half millimeters
Millimeter (mm) is SI metric linear unit of measurement for engineering drawings
Conversion tables change dimension in one system to another

24. Bases for Blueprint Reading and Sketching
Assignment-Unit 1