Cutting Operation; Preliminaries; Cutting - Helvi PC75 Manual De Uso

PRELIMINARIES

WARNING
unplug the unit from the power supply
before assemble or disassemble piled
parts, single parts, parts of the torch,
torch assemblies or cables.
• Check and follow instructions as foreseen in
the paragraphs "Safety and Installation" of
the present instructions manual.
PARTS OF THE TORCH
• Check the torch for proper assembly (refer
to Section called Torch Consumable Parts
Mounting).
• Install proper torch parts for the desired ap-
plication (refer to Section called Torch Consu-
mable Parts Selection).
INPUT POWER
• Check the power source for proper input vol-
tage.
• Plug unit in and close main disconnect switch
to supply primary power to the system.
GROUND CABLE
• Check for a solid ground cable connection to
the workpiece.
AUTOMATIC PURGE SYSTEM
• Place the ON/OFF switch to the ON position.
Activate the torch button to initiate 3s gas
purge (pre-flow) to remove any condensation
that may have accumulated in the torch and
leads while the system was shut down. When
the gas purge is complete, pilot arc will be
initiated. To cool torch handle or to further
remove condensation in the torch and leads
push the torch gas purge button (8) on the
front panel of the unit.
WARNING
Do not initiate pilot arc during adjustment.
CHECKING AIR QUALITY
• To check air quality, deactivate the torch (post-
flow) and place filter lens in front of the torch.
Any oil or moisture in the air will be visible
on the lens. DO NOT initiate pilot arc while
checking air quality.
AIR PRESSURE REGULATION
• Adjust the air pressure by pushing the air pur-
ge button (8) and by acting on the air regu-
lator (9) The display shows the adjusted air
pressure in bars. The Bar Led (11) is on.
CUTTING CURRENT REGULATION
• Adjust the cutting current by acting on the ou-
tput current knob (2).
EN-10

CUTTING OPERATION

CUTTING

CUTTING WITH A HAND TORCH
• The torch can be comfortably held in one
hand or steadied with two hands. Choose the
technique that feels most comfortable and
allows good control and movement. Position
the index finger or thumb to press the control
switch on the torch handle.
• For edge starts, hold the torch perpendicular
to the workpiece with the front of the tip on
the edge of the workpiece at the point where
the cut is to start - Fig. 15.
Figure 15
• For piercing, angle the torch slightly to direct
sparks away from the torch until the pierce is
complete - Fig. 16
Figure 16
• For drag cuts keep the torch in contact with
the workpiece. For standoff cutting, hold the
torch 2-3 mm from the work.
• With the torch in starting position, press the
control switch. After an initial gas purge (pre-
air), the pilot arc will come on and remain on
for 3 seconds until the cutting arc starts.
• Once on, the main arc remains on as long
as the control switch is held down, unless the
torch is withdrawn from the work or torch
motion is too slow. Keep moving while cut-
ting. Cut at a steady speed without pausing.
Maintain the cutting speed so that the arc lag
is about 30° behind the travel direction. Fig.
17. If the cutting arc is interrupted, and the
torch trigger is still pressed, the pilot arc co-
mes back on automatically for 3 seconds.
• To shut off the torch simply release the control
switch. When the switch is released a post-
flow will occur. If the torch trigger is pressed
during the post-flow, the pilot arc will restart.