رشا

• Numerical control (NC)


  A method of automatically operating a manufacturing machine based on a code of letters, numbers, and special characters
• NC machine programming

  1. Written instructions converted into a corresponding hole pattern on tape

  2. Tape reader reads hole pattern and converts to electrical signal code

  3. Controller receives electrical signal code and causes NC machine to respond

  4. NC machine executes required motions to manufacture a part

  
• NC machine tools

  • One or more of the following functions may be automatic: starting/stopping spindle, controlling spindle speed, positioning/guiding tool tip, controlling feed rate, changing tools
• Functions of a machine tool

  • Hold work piece and cutting tool securely
  • Provide sufficient power to enable tool to cut work piece material at economical rates
  • Displace tool and work piece relative to one another to produce required work piece shape with desired accuracy and surface finish
• Computer Numerical Control (CNC)


  Characterized by availability of dedicated computer and enhanced memory in controller, providing additional capabilities over traditional NC

  
• Additional capabilities of CNC over traditional NC

  • Part program storage memory
  • Part program editing
  • Part program downloading and uploading
  • Part program simulation using tool path
  • Tool offset data and tool life management
  • Additional part programming facilities
  • Macros and subroutines
  • Background tape preparation
• The controls with the machine tools these days are all CNC and the old NC control do not exist anymore