Version 1.0, August 31, 2001, Copyright, Hugh Jack 1993-2001

43.2.1 NC Tapes

 

· NC Programs are preprocessed on computers, and punched onto paper or mylar tapes.

 

· Simple NC machines can use a tape reader to direct the machine.

 

· Problems,

  1. - required storage, transportation, and manual loading of NC tapes
  2. - has to reread the tape for each new part
  3. - tapes tend to wear, and become dirty, thus causing misreadings
  4. - the readers are slow, and can cause `dwell marks' on complex pieces
  5. - the mechanical parts in the readers reduced reliability
  6. - testing had to be done on the NC machine
  7. - no program editing abilities (increased lead time)

 

· The end of tapes was the result of two competing developments

  1. - DNC used remote computers to replace tape readers, these were displaced in most cases by CNC
  2. - CNC allowed the use of a local computer to overcome problems with tapes, and the problems with distant computers. While CNC was used to enhance tapes for a while, they eventually allowed the use of other storage media, and currently program transfer media are not required.