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

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

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

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

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

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

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

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

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)

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

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

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

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

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

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

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

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

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

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

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

Bases for Blueprint Reading and Sketching Assignment-Unit 1