Cebora PLASMA PROF 122 Instruction Manual page 14

The following may cause this problem:
• Speed too high:
Always make sure that the arc cuts completely through the
workpiece, and that it is never slanted at an angle of more than
10°-15° in the moving direction. This will avoid incorrect con-
sumption of the tip and burns on the shield cup.
• Workpiece is too thick (see cutting speed and thickness
diagram, fig. 9)
• Work clamp is not in good electrical contact with the workpiece.
• Tip and electrode are worn.
• Tip hole is too large with respect to the current value set on the
knob F.
• Cutting current is too low.
NOTE: When the arc does not penetrate, the melted metal waste
may damage the tip hole.
3.2 THE CUTTING ARC GOES OFF
The following may cause this problem:
• tip, electrode or diffusor is worn;
• air pressure is too high;
• power voltage is too low;
• advancement speed is too slow;
• cutting current is too high in relation to the thickness of the
workpiece.
3.3 THE CUT IS SLANTED
If the cut is slanted, turn off the machine and replace the tip.
Prevent the tip from coming into electrical contact with the
workpiece (even through shreds of melted metal).
This causes the nozzle hole to be destroyed rapidly, at times
instantaneously, and leads to a poor quality cut.
3.4 EXCESSIVE WEAR ON THE CONSUMABLE PARTS
The following may cause this problem:
• air pressure is too low with respect to the recommended value;
• air supply circuit is damaged.
4 HELPFUL HINTS
• If the air in the system contains considerable amounts of
moisture and oil, it is best to use a drying filter to avoid excessive
oxidation and wear on the consumable parts, damage to the
14
torch, and reduced cutting speed and quality.
• Impurities present in the air can also make it difficult to light the
pilot arc. If this occurs, clean the end of the electrode and the
inside of the tip using very fine sandpaper.
• Make sure that the new electrode and tip about to be mounted
have been thoroughly cleaned and degreased.
• To avoid damaging the torch, always use original CEBORA
replacement parts.
5 TORCH MAINTENANCE (FIG. 10)
Always cut off power to the machine before working on the torch.
5.1 REPLACING THE CONSUMABLE PARTS
The parts subject to wear are the electrode G, the diffusor F, and
the tip E.
Any of these parts may be replaced only after unscrewing the
shield cup D.
The electrode to be replaced has a crater in the middle,
approximately 1.5 mm deep.
If this is not replaced when worn, the device blocks itself and the
indicator lamp E lights (Fig. 2). To reset, you must turn off the
device, replace the electrode and turn it back on using the knob
A.
CAUTION! Do not use sudden force to unscrew the electrode;
exert a gradually progressive force until the threading is re-
leased.
Lubricate the threading of the new electrode using silicone
lubricant (provided with the machine).
The new electrode must be screwed into its housing and
fastened in place without over tightening.
The tip should be replaced when the central hole is damaged or
much wider than that of a new tip. The diffusor F should be
replaced when one of its ends tends to char. Often, due to the
thermal and mechanical stress to which it is subjected, this part
tends to stick to the electrode G or the tip E. To detach it, we
suggest that you use the extractor O provided with the device,
which allows you to detach the diffusor without damaging it.
Make sure that the electrode A, the diffusor B and the tip C have
been mounted correctly, and that the shield cup D is screwed on
tightly.
fig. 10