Lincoln Electric IM590 PRO-CUT 55 - Manual (Page 18)

B-6 OPERATION B-6
PILOT ARC DISCUSSION
The PRO-CUT has a smooth, continuous pilot arc.
The pilot arc is only a means of transferring the arc to
the workpiece for cutting. Repeated pilot arc starts, in
rapid succession, is not recommended as these starts
will generally reduce consumable life. Occasionally,
the pilot arc may sputter or start intermittently. This is
aggravated when the consumables are worn or the air
pressure is too high. Always keep in mind that the
pilot arc is designed to transfer the arc to the work-
piece and not for numerous starts without cutting.
When the pilot arc is started, a slight impulse will be
felt in the torch handle. This occurrence is normal and
is the mechanism which starts the plasma arc. This
impulse can also be used to help troubleshoot a "no
start" condition.
PROCEDURE RECOMMENDATIONS
When properly used, plasma arc cutting or gouging is
a very economical process. Improper use will result in
a very high operating cost.
General - In All Cases
• Follow safety precautions as printed throughout
this operating manual and on the machine.
Thin Gauge Sheet Metal:
Output set below mid-range.
• The nozzle may be dragged on the metal sur-
face, touching it lightly to the surface after pierc-
ing a hole. Current control should be set below
the mid range.
• Do not allow cable or body to contact hot sur-
face.
Thick Sections of Metal
Output set above mid-range.
• The best quality and consumable life will be
obtained by holding the torch off the surface
about 3/16". Too long an arc may compromise
cut quality and consumable life. The nozzle
should NOT be dragged on the work.
• Use of the S22151 Drag Cup will maintain the
proper standoff. The only reason not to use the
Drag Cup when the output control is set above
mid-range is in special, tight corners. Always
hold at least a 1/8" standoff in those situations.
• If piercing is required, slowly lower the torch at
an angle of about 30 ° to blow the dross away
from the torch tip and slowly rotate the torch to
a vertical position as the arc becomes deeper.
This process will blow a lot of molten metal and
dross. Be careful! Blow the dross away from
the torch, the operator and any flammable
objects.
• Where possible, start the cut from the edge of
the work piece.
• Keep moving! A steady speed is necessary.
Do not pause.
• Do not allow torch cable or body to contact hot
surface.
PRO-CUT 55
Torch Standoff
DRAG thru 1/16"
Standoff
Output Setting
Min. thru Mid. Range
Machine Output Setting
Torch Standoff
1/8" thru 3/16"
Standoff
Output Setting
Mid. thru Max. Range
Machine Output Setting