Top Dross; Dross Formation - ESAB B Series Installation, Operation And Maintenance Manual

SECTION 5
End View
Cut Face
Figure 5-6. Cut Quality (Arc Voltage Too Low With An Under Cut Top Edge)

5.3 TOP DROSS.

Top dross usually appears as splatter near the top edge
of the kerf. This is a result of torch standoff (arc voltage)
set too high or a cutting speed set too fast. Use the
parameter charts for recommended speed. The most
common problem is torch standoff or arc voltage control.
Simply lower the voltage settings in increments of 5 volts
until the top dross disappears. If an arc voltage control is
not being used, simply lower the torch manually until the
top dross disappears (Figure 5-7).
Arc Voltage
Under Cut
Top Edge
-/+ Cut Angle

5.4 DROSS FORMATION.

The correct cutting arc voltage also has an influence on
dross formation. If the arc voltage is set too high, the cut
angle becomes positive. In addition, dross forms on the
bottom edge of the part. This occurs because we are now
trying to cut the part with the feather tip of the plasma arc.
This dross is usually very tenacious and requires chipping
and grinding for removal. Too low of a cutting voltage
results in an undercutting of the parts or negative cut
angle. Dross formation usually occurs but in most cases
removes easily (Figure 5-6)
74
CUTTING QUALITY
ARC VOLTAGE TOO LOW
Correct Cutting Speed
Under Cut Top Edge
Negative Cut Angle
Dross
Cut Face Rough
Vertical Serrated Lag Lines