Hypertherm HT4001, Instruction Manual

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OPERATION
HT4001 Instruction Manual
Dross Conditions
1. Low Speed Dross
• This type of dross is caused when the travel speed is too slow, and the arc shoots
ahead. It forms as a heavy bubbly deposit at the bottom of the kerf and can be easily
removed. Normally, increasing the speed will reduce the dross.
2. High Speed Dross
• This type of dross is caused when the travel speed is too fast, and the arc lags
behind. It forms as a thin, linear bead of solid metal attached very close to the kerf.
The dross appears to be a fused continuation of the kerf wall. It is welded to the
bottom of the cut and is very difficult to remove. Reduce high speed dross by
decreasing the travel speed. If this does not remove the dross, lower the torch
standoff distance by decreasing arc voltage.
3. Dross comes and goes
• Caused by worn consumable parts.
• Dross can be material dependent.
• Dross formation dependent on metal temperature. Warm and hot metal is much
more prone to dross accumulation than cool metal. For example, the first cut in a
series of cuts will most likely have the least amount of dross. As the workpiece heats
up, dross levels are likely to increase on the subsequent cuts.
Shape of Cut Surface
The ideal shape of the cut face is straight. Sometimes the cut face becomes either concave
or convex. Maintain the correct torch height and cut speed to keep the cut face straight.
1. Concave cut face (bevel on inside)
• Caused by standoff distance being too low. Increasing the arc voltage will increase
the standoff distance and straighten the cut face.