Forch AC 71 Manual Del Usuario página 96

RULES FOR THE CUTTING PROCESS
When starting the process, initially a so-called pilot arc is ignited between the electrode
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(negative pole) and the nozzle (positive pole) in the cutting torch.
When the cutting torch touches the workpiece (nozzle), then the pilot arc is transmitted
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between the electrode and the workpiece and thereby ignites the actual plasma arc.
After actuating the start button on the cutting torch, the pilot arc will ignite. If the plasma
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arc is not transmitted to the workpiece within 3 seconds (torch nozzle must touch the
workpiece), then the pilot arc will switch off for safety reasons. Air will continue to flow for a
certain length of time afterwards to cool the torch.
The cutting torch can easily be held in one hand or both hands. Select the method which is
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most comfortable for you and gives you good control and freedom of movement. Place your
thumb and index finger is a position so that you can press the torch button on the torch handle.
Cuts without incision, usually starting from an outer edge of the workpiece. When doing so,
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the cutting torch should always be held vertically (Fig. A). Before placing the cutting nozzle
on the workpiece, the pilot arc needs to be started. Then guide the cutting torch to the
place where you want to start the cut.
Fig. A
Fig. C
When cutting with an incision, angle the cutting torch slightly (Fig. B). This ensures that the
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melt is blown away from the cutting torch and protects the wear parts. Once the plasma arc
has penetrated through the material, then you can continue to cut with the cutting torch in a
vertical position (Fig. D).
IMPORTANT!
The recommended maximum workpiece thickness for stabbing is 2 mm. If you need to cut
a workpiece which is more than 2 mm thick and cannot start at the edge, then pre-drill a
hole at least 6 mm across before cutting.
CUTTING PROCESS WITH HAND TORCH
To start, hold the cutting torch near the starting position and press the torch button.
After the initial gas cleaning (3 seconds), the pilot arc is started. Now apply the cutting
nozzle to the workpiece. If the plasma arc does not start within 3 seconds after starting the
pilot arc, then for safety reasons the start is aborted and the pilot arc is switched off.
Always apply the cutting nozzle to the workpiece when cutting. The plasma arc will only
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burn as long as the torch button is pressed or until a malfunction occurs. To avoid a mal-
function, keep the speed you are cutting at as even as possible, without stopping.
The cutting angle is right if the plasma arc is at an angle of approx. 30° from the vertical
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(Fig. C).
Fig. B
Fig. D