Hypertherm HRT - Manual (Page 89)

OPERATION
Duramax Retrofit Torch
Operator Manual
3-53
To pierce a workpiece using the machine torch
As with the hand torch, you can start a cut with the machine torch at the edge of the workpiece or
by piercing the workpiece. Piercing will result in a shorter consumable life than with edge starts.
The pierce delay must be sufficiently long that the arc can pierce the material before the torch
moves, but not so long that the arc “wanders” while trying to find the edge of a large hole.
When piercing maximum thicknesses, the ring of dross that forms during the pierce may become
high enough to contact the torch when the torch begins to move after the pierce is complete.
Remove the dross if the torch will contact it during the cut.
Common machine-cutting faults
The torch’s pilot arc will initiate, but will not transfer. Causes can be:
• The work cable is not making good contact with the cutting table or the cutting table is not
making good contact with the workpiece.
• The torch‑to‑work distance is too large.
The workpiece is not totally penetrated, and there is excessive sparking on the top of the
workpiece. Causes can be:
• The consumables are worn and need to be replaced. For optimized performance in a
mechanized application, replace the nozzle and the electrode together.
• The work cable is not making good contact with the cutting table or the cutting table is not
making good contact with the workpiece.
• The current (amperage) is set too low. See “Using the cut charts” on page 3‑3 for more
information.
• The cut speed is too high. See “Using the cut charts” on page 3‑3 for more information.
• The metal being cut exceeds the maximum capacity for the selected amperage.