Setting At Work - Elettro plasma 75 Instruction Manual

1. Unscrew the screws M6X16 on the front panel. Slip the
flange 1 on the torch 2 and screw the torch in the adapter 3.
Insert the flange positioning the insert with the spring in the
corresponding hole on the panel of the machine. Block the
flange with the screws M6X16 in the holes with the thread
inserts.
2. For the replacement of the torch, unscrew the screw M6X16,
take away the flange 1 and unscrew the torch 2 from the
adapter 3. For the assemblage of the new torch follow the
instructions at the point 1.
Pay particular attention not to dent the power pin and not to
bend the adapter pins; a dented pin cannot be disconnected,
once fit from the fixed fitting R (pict. 1) a bent pin prevents the
adapter from being correctly mounted on the fixed fitting R
(pict.1) and the unit from working.
This machine is suitable for ELETTRO CF torches type P 70
and P 150 only, either manual or automatic and ELETTRO
CF do not assume any responsibility in case that a
different kind of torch is used.

3.2 SETTING AT WORK

The unit must be installed by skilled personnel. All fittings
must be in conformity with the existing rules and in full
compliance with safety regulations. Connect the air feed to
fitting on the air pressure reduction unit P (pict. 2) making sure
that pressure is 88PSI (6bar or KPaX100) at least with a
minimal capacity of 420 CFH (200 litres/min). Should air feed
come from a pressure reducing unit of a compressor or of a
centralized plant, the reducing unit should be adjusted at the
highest out put pressure which should not exceed 120 PSI
(8bar or KPax100). Should air feed come from a compressed
air bottle, this should be provided with a pressure regulator;
never connect compressed air bottles directly to the
reducing unit! Pressure may exceed the reducing unit
capacity and then explode!
Check that the mains power supply matches that indicated on
the technical date plate. Connect supply cable Q (pict.2) the
yellow-green wire of cable must be connected to an efficient
earth plug of the system, the remaining wires should be
connected to the feed line by means of the switch placed, if
possible, close to the cutting area so as to switch the unit off
quickly if necessary. The magnetothermic switch capacity or of
fuses in series with switch should be equal or above the current
I absorbed by the unit. Current I
1
reading the technical specifications on the unit i.e. feed voltage
U available. Any extensions should have adequate sections for
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current absorbed I .
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3.3 USE
Switch the unit on by turning knob N (pict.2) of the mains
switch; this is shown by light E (pict.1) which is on.
By pressing for a second the torch button, the compressed air
flow is opened. Check that, under this condition, the pressure
shown on gauge O (pict. 2) is about 75 PSI (4,5÷4,7 bar or
KPaX100), otherwise adjust it by means of knob of reducing
unit P (pict. 2), then lock this knob by pressing it down. Connect
work clamp to the piece to be cut. Set the cutting current by
means of the knob C (pict.1). Use the Ø 1 mm nozzle up to 45
÷ 50 A and the Ø 1,2 mm one from 45 to 70 A.
N.B. Cut quality is greatly improved if the nozzle is kept at
a distance of approx. 2 mm from the workpiece. Often for
practical reasons, however, cutting is performed with the
nozzle in contact with the workpiece. Cutting with the
absorbed is known by
1
nozzle in contact with the workpiece must not be
performed at currents above 45A as this leads to rapid
(sometimes even instantaneous) destruction of the nozzle
hole; this in turn leads to poor cutting quality. When the
red warning light D (pict.1) lights up this indicates that
cutting must be performed using the different spacer.
Clean the work piece to ensure good electrical contact of the
work clamp. Do not connect work clamp to the material to be
removed. Press torch button to start pilot arc, if cutting does not
start after 4 seconds, the pilot arc turns off and the button
should be pressed again to repeat the operation. When
possible, the torch should be pulled. Pulling is easier than
pushing. Keep torch in vertical position when cutting. Once
cutting is over and after releasing button, air continues to flow
out of the torch for about 1 minute so it enables torch to cool
down. It is recommended not to turn the unit off before that
time. Should holes be drilled or should the piece be cut starting
from its centre, torch should be tilted and then slowly straighten
to prevent molten metal from being spread on nozzle (see
picture4). This operation should be carried out with material
thickness above 1/8" (3 mm). If you have to cut near angles or
recesses (see picture 5) it is recommended to use extended
electrodes and nozzles. Should circular cut be done it is
recommended to use caliper (supplied on request).
N.B. : Avoid keeping pilot arc uselessly on, in air to avoid
electrode, diffuser and nozzle consumption.
3.4 CUTTING TROUBLE
1) Insufficient penetration
This may be due to:
• high speed. Always make sure that arc thoroughly passes
through the piece to be cut and that it is not tilted, when going
forward, by a percentage above 10 ÷ 15° (see picture 6). It is
thus avoided to wear nozzle (see pict. 7) out and to burn the
nozzle holder (see picture 8).
• Excessive thickness of piece (see graph of cutting speed and
thickness)
• Work clamp not properly in electric contact with piece
• Worn nozzle and electrode
• Too low cutting current.
N.B.: When the unit does not thoroughly pass through, nozzle
is clogged by scums.
2) Cutting arc switches off
This may be due to:
• worn nozzle, electrode or diffuser
• too high air pressure
• too low feed voltage
3) Tilted cutting
When cutting is tilted (see pict. 9) switch the unit off, loosen
nozzle holder and turn nozzle by a quarter turn, then lock and
try again. Repeat until cutting is straight (see pict. 10).
4) Excessive wear of consumable parts
This may be due to:
a) too low air pressure with respect to the recommended one.
b) excessive burns on the end part of nozzle holder.
3.5 PRACTICAL RECOMMENDATIONS
• If the system air contains much humidity and oil it is required
to use a drying filter to avoid excessive oxidation and wear of
consumable parts, to avoid torch damage or to reduce speed
and quality of cutting.
• Impurities of air favour oxidation of electrode and nozzle and
make it difficult to start pilot arc. If this occurs, clean the end
part of electrode and inside the nozzle with fine abrasive
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