Dross Formation - ESAB ESP-101 Manuel D'instruction

SECTIoN 4
4.5

Dross formation

Cutting speed, gas selection and variations in metal composition contribute to dross formation. The correct cut-
ting standoff 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 dross can be tenacious and require chip-
ping and grinding for removal. Setting the cutting voltage too low results in undercutting the parts or negative
cut angle. Dross formation occurs but in most cases it is easily removed.
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 cutting speed set too fast. Most operators 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 used, the torch can be lowered manually
until the dross disappears.
ToP DroSS:
hIgh SPEED DroSS:
loW SPEED DroSS
SuMMarY
Arc voltage is a dependent variable. It is dependent upon cutting amperage, nozzle size, torch standoff, cut gas
flow rate and cutting speed. An increase in arc voltage can result from a decrease in cutting speed, an increase
in cutting amperage, a decrease in nozzle size, an increase in gas flow and an increase in torch standoff. Assum-
ing that all of the variables are set as recommended, torch standoff becomes the most influential variable to the
process. Good and accurate height control is a necessity in producing excellent cut quality.
Splatter appears on the top edge of
both pieces of the plate.
lower the voltage in increments of 5
volts DC (maximum) until top dross
disappears.
fine roll over dross that welds to
bottom of edge. Cleaning requires
chipping or grinding.
globular dross that forms in large
deposits. Comes off very easily.
figure 4-6. Dross formation
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oPEraTIoN