Recurring Backflow / Abrasive Clogs

If you find that after a backflow or a abrasive clog, you get another immediately or even shortly after, the situation indicates that you have other problems waiting to be solved. There are two likely root causes.

The most likely cause of a backflow is the nozzle comes in contact with the work piece or with a popup.

Check: Is the Cut Bed Level?

  • Root Cause:  If the cutting bed is not level, you may accidentally adjust your nozzle offset at a low part of the cute piece. During the operation, the nozzle will touch one of the high parts of cut piece.
  • Corrective Action:  Leveling or Replacing the cutting bed will ensure that the nozzle does not touch the work piece.
Check: Is the Cut Bed too chewed up?
  • Root Cause: If the cutting bed is completely used up, it may not have the rigidity to keep your material flat.
  • Corrective Action:  Flip or replace the Cut Bed will ensure that the work piece is well secured and the nozzle does not touch it.

Check: Were tabs enabled in WAM?

  • Root Cause: If a part that is cut out floats up and gets between the nozzle and  the work piece this will cause a back flow
  • Corrective action:  Enable tabs in WAM.  The tabs only need to be large enough so the piece is just held

Check: Is the Z-adjusting knob tight before starting the cut?

  • Root Cause: If the head were to drop into the work piece during the cut, it would cause a backflow.
  • Corrective Action: Check that the knob is tight before every cut

Check: Is the abrasive valve fully closing?

Check: Is the low pressure inlet below 25 psi or are there sudden drops in inlet pressure?

  • Root Cause:  Low supply pressure will cause the high pressure output of the pump tp dip momentarily.  These dips mess with the suction of the of abrasive into the head and can lead to water and abrasive mixing in the abrasive hose. Lading to a clog
  • Corrective Action:  Make sure the inlet pressure is to spec and that no water hungry devices (utility sink, washer, etc) are turned on during a cut

Check is the orifice in good health? Follow the guide here to check the stream.

  • Root Cause: A slightly damaged orifice will look similar to a working one once the stream has been focused by the nozzle.  Despite how it looks the cutting potential is greatly reduced.
  • Corrective ActionReplace the Orifice

Check:  Is there a knocking coming from the pump box.  

  • Root Cause:  When the orifice is broken the pressure setting device on the pump struggles to achieve pressure and make a loud noise
  • Corrective Action  Replace the Orifice