CAD

• Computer-aided drafting (CAD) is a technical process in which engineering or design-related personnel use computer systems and software to draft architecture or objects
• CAD is used to create 2D and 3D drawings, models and plans for tangible items
• Engineering drawing


  A graphical means of expression of technical details without the barrier of a language. It is the universal language for engineers since no construction/manufacturing of any (man-made) engineering objects is possible without engineering drawing
• Drafting


  A graphic language using lines, symbols, and notes to describe objects for manufacturer or construction
• Mechanical Drafting


  Drafting of heating, ventilating and air-conditioning (HVAC) systems, which is the mechanical portion of an architectural project
• Manual drafting


  Traditional drafting practice through the use of pencil or ink medium such as paper or polyester film and with the use of drafting instruments and equipment
• Computer-aided drafting (CAD)


  Computers are used for drafting instead of manual drafting
• Engineering drawings communicate a variety of concepts such as engineering requirements, instructions, and proposal to a variety of people
• An engineering drawing provides all of the data required to manufacture or construct an item or product such as a machine part, consumer product, or structure
• Prehistoric drawings


  • Pictograms and petroglyphs showing a variety of animals and human shapes, but not considered engineering drawings
• Early engineering drawings representing machines and buildings appear in the fourteenth and fifteenth centuries
• Early engineering drawings


  • Served as a reference for craft workers to construct a building or manufacture a product
• Descriptive geometry


  The system of graphic geometry that uses plane projections to describe and analyze their properties for engineering drafting applications

  
• Early drafters had degrees in engineering and began to realize the importance of creating accurate and detailed engineering drawings
• Graphic language in engineering application


  Uses lines to represent the surfaces, edges, and contours of objects
• Drafting


  The basic technical form for visual communication, translating the technical ideas, sketches, and the data of engineers and designers into clear, easy-to-read working drawings
• Interchangeability


  Parts manufactured identically within given tolerances, so one part can replace another part without the need for custom fitting
• Early drafting equipment


  • Pencil, T-square, Triangles, Irregular (French) curves, Compasses, Dividers

  
• Vertical uppercase Gothic lettering


  Specific lettering style used by engineering drafters
• Drafting machine


  Replaced the T-square, triangles, scales, and protractor for creating drawings
• Blueprint


  A contact chemical-printing process of a drawing or other image copied on paper with white lines on a blue background
• Diazo process


  Created a blue line copy with a white background, replacing the blueprint process
• Drafting equipment


  • Scales
  • Protractor
  • Used for creating drawings
• During the decades after World War II, drafting equipment suppliers introduced a variety of materials to improve the productivity of the drafting process
• Until recently, all drawing reproductions were called blueprints
• Today, offices use printers, plotters, and engineering copies that use xerography to reproduce computer-aided drafting and design (CADD) drawings
• The generic term print has replaced the term blueprint
• Drafters must possess


  • Broad understanding of drafting knowledge and skills
  • Specific knowledge of the manufacturing methods and standards in the specific industry
• Drafters must


  • Understand the basics of drafting and design
  • Be familiar with the basic types of engineering drawings
  • Clearly communicate ideas with the freehand sketches
  • Be proficient with computer-aided drafting and design systems
  • Have some skill with manual drafting instruments
• Major types of drawings


  • Multiview drawings
  • Pictorial drawings
  • Schematic drawings
  • Block diagrams
• Multiview drawings


  Two-dimensional (2-D) views of the object drawn using orthographic projection wherein the complete shape of the item with its dimension and details is shown

  
• Pictorial drawings


  Three-dimensional (3-D) drawings that show an object as in a photograph wherein usually three adjacent surfaces are shown in one drawing

  
• Schematic drawings


  Drawings that use symbols and lines to show the flow of energy or fluids
• Block diagrams


  Used to show the flow of a working process
• Drafting fields


  • Electrical Drafter
  • Electronic Drafter
  • Technical Illustrator
• Electrical Drafter


  Generate computer-aided drafting and design (CADD) models and drawings of electrical equipment, wiring diagrams, circuit-board assembly diagrams, and layout drawings used by construction crews and repairers
• Electronic Drafter


  Produce CADD models and drawings that includes wiring diagrams, layout drawings, mechanical detail drawings, intermediate and final assembly drawings used in manufacturing, assembling, installing, and repairing electronic devices and components, printed circuit boards and equipment
• Technical Illustrator


  Lay out and draw illustrations for reproduction in reference works, as well as brochures and technical manuals that deals with assembly, installation, operation, maintenance, and repair of machine, tools, and equipment
• Most industries, companies, even schools establish standards
• Standards


  Guidelines that specify drawing requirements, appearance, techniques, operating procedures, and record-keeping methods