8695 4387 / H
F - UTILISATION DE L
’INSTALLATION PLASMA
EASYTOME
F-27
8 - RECOMMENDATIONS FOR START AND END PORTIONS
For internal cutting (e.g. making holes):
A straight or circular start portion may be used
End portions are not recommended by LINCOLN ELECTRIC(*)
because they significantly reduce the
life of nozzles and plasma electrodes.
For external cutting:
A straight start portion is recommended when the part has a right or sharp angle.
A circular portion may be used if the entry is placed at the middle of a path
End portions are recommended by LINCOLN ELECTRIC because they allow the torch to be clear if the
part tilts.
(*) What happens in the torch when the plasma leaves the material (inside of a hole for example) :
The arc stretches and flattens the nozzle
When the arc is cut off suddenly, the molten emissive material is massively pushed out of the nozzle
The cooled material remains deposited inside the nozzle.
The plasma jet would thus be rapidly deformed (flattening and deposit) and the cutting quality would be
degraded earlier.
