Cutting Operations; Troubleshooting Guide - Prima PP 35 Manuel D'instructions

CUTTING OPERATIONS

PRELIMINARIES
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Check and follow instructions as foreseen in the paragraphs "Safety and Installation" of the present
instructions manual.
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Close (bring position I) automatic mains switch and general machine switch in sequence.
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Chose, by turning the cutting current potentiometer, the most suitable position to the work to be performed.
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Push and release air test trigger causing air outflow (>30s post air)
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During this phase, set air pressure till gauge indicates value in "bar" requested according to the torch in use
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Let air outflow to terminate spontaneously to facilitate removal of condense which settled on the torch.
CUTTING
Warning: the machine is protected against the chance stricking of the pilot arc.
Making an unprepared contact cut will cause rapid wear of the torch nozzle. Bring the torch nozzle near the
edge of the workpiece (3mm), press the torch button; release it and press it again within 3 seconds
(protection system against chance stricking of the pilot arc); after approx. 0.5 seconds (pre-air) the pilot
arc is struck (max duration 2 sec.) If the distance is correct, the pilot arc immediately transfers to the workpiece
causing the cutting arc to be struck.
Move the torch on the surface of the workpiece making steady progress along the ideal cutting line. Adjust the
speed according to the thickness and selected current, and check that the arc coming out of the lower surface of
the workpiece has an inclination of 5-10° to the vertical on the opposite direction to the cutting direction.
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An excessive distance torch-workpiece or the absence of material (end cut) causes the immediate
interruption of the arc.
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Interruption of the arc (cutting or pilot) is obtained by releasing the torch button.
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Piercing: if you have to make this operation or you have to start from the center of the workpiece,
ignite keeping the torch tilted and bring it to an upright position with a smooth movement.
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This procedure avoids that returns of the arc or melted parts spoil the hole of the nozzle reducing its
functionality.
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Piercing of parts with a thickness of 25% of max. usuable foreseen, may be carried out directly.
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For peculiar uses (ex. cutting of pierced sheets or cutting with mechanized torch) contact an after-
sale center.

TROUBLESHOOTING GUIDE

During cutting operations performance faults may arise which are not caused by plant malfunctioning but
by other operational faults such as:
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Insufficient penetration or excessive scoria
settlement:
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Interruption of the cutting arc:
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Tilted cutting (not perpendicular):
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Excessive wear of nozzle and electrodes:
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too high cutting speed;
torch is too tilted;
piece is too thick
electrode and nozzle are worn out;
cutting speed too low;
excessive distance between torch and workpiece;
electrode is worn out;
intervention of the protections;
Torch position not correct;
asymmetric wear of nozzle hole and/or wrong
assemblage of the torch parts;
air pressure too low;
contaminated air (humidity-oil);
nozzle holder damaged
excessive pilot arc arc ignitions in the air.