Friday, December 12, 2008

advantage of wjm over EDM

  • Abrasive jets are much faster than EDM.
  • Abrasive Jets machine a wider variety of materials (virtually any material).
  • Uniformity of material is not very important to an Abrasivejet.
  • Abrasive jets make their own pierce holes.
  • Abrasive jets do not heat the surface of what they machine.
  • Abrasive jets are capable of ignoring material aberrations that would cause wire EDM to lose flushing.
  • Abrasive Jet machining is useful for creating start holes for wire insertion later on. (a mill could do the job, but only after spotting the hole, changing tools to drill a pilot, then changing tools again to drill out the hole).
  • New technology allows Abrasive jets to obtain tolerances of up to +/-.003" (0.075mm) or better (I have personally done some +/-.001" (0.025mm) work, but that's the exception, not the norm, and only on certain shapes and materials.)
  • No heat affected Zone with Abrasive jets.
  • Abrasive jets require less setup.
  • Make bigger parts.
  • Many EDM shops are also buying waterjets. Waterjets can be considered to be like super-fast EDM machines with less precision. This means that many parts of the same catagory that an EDM would do can be done faster and cheaper on an abrasivejet, if the tolerances are not extreme.
Wire EDM fixturing in an abrasivejet machining center. This makes precision fixturing possible. It also allows for pre-machining on the abrasive jet to release stresses in the material, and then use the exact same fixturing on the EDM to do secondary operations and final cutting to extreme tolerance.

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