Elettro MIG 2400 Manuel D'instructions page 9

4.2. POSITIONING THE COOLING UNIT FOR ITEM 271 (see
pict. 6)
Remove the eyebolts from the roof of the machine (if
mounted), and then use them to fasten the cooling support,
provided in the kit supplied with the cooling unit.
Remove the four screws from the housing of the cooling unit
(art. 560010.A25), as shown in drawing 6, and use them to
secure the cooling unit on the support provided in the kit
supplied with the cooling unit.
Connect the two extensions for cooling hoses, supplied with
the kit of the cooling unit, to the hoses of the water-cooled
torch and to the cooling unit, respecting the colours shown on
the cooling unit.
4.3. THE MACHINE IS READY TO WELD
• Connect the earth clamp to the workpiece.
• Set the switch C to 1.
• Remove the gas nozzle.
• Unscrew the contact tip.
• Insert the wire in the wire liner of the torch, making sure that it
is inside the roller groove and that the roller is in the correct
position.
• Press the torch trigger to move the wire forward until it comes
out of the torch.
• Caution: keep your face away from the gun tube
assembly while the wire is coming out.
• Screw the contact tip back on, making sure that the hole
diameter is the same as that of the wire used.
• Assemble the gas nozzle.
4.4. WELDING CARBON STEELS WITH GAS PROTECTION.
In order to weld these materials you must:
• Use a welding gas with a binary composition, usually ARGON
+ CO2 with percentages of Argon ranging from 75% up. With
this blend, the welding bead will be well jointed and attractive.
Using pure CO2 as a protection gas will produce narrow
beads, with greater penetration but a considerably increase in
splatters.
• Use a welding wire of the same quality as the steel to be
welded. It is best to always use good quality wires, avoiding
welding with rusted wires that could cause welding defects.
• Avoid welding rusted parts, or those with oil or grease stains.
4.5. WELDING STAINLESS STEEL
Series 300 stainless steels must be welded using a protection
gas with a high Argon content, containing a small percentage
of O2 or carbon dioxide CO2 (approximately 2%) to stabilize
the arc.
Do not touch the wire with your hands. It is important to keep
the welding area clean at all times, to avoid contaminating the
joint to be welded.
4.6. WELDING ALUMINIUM
In order to weld aluminium you must use:
• Pure Argon as the protection gas.
• A welding wire with a composition suitable for the base
material to be welded.
• Use mills and brushing machines specifically designed for
aluminium, and never use them for other materials.
• If only a torch prepared for steel wires is available, it must be
altered as follows:
- Make sure that the cable is no more than 3 meters long.
- Remove the brass liner nut, gas nozzle, contact tip, and
then slip off the liner.
- Insert our graphite liner (optional), making sure that it
protrudes from both ends.
- Screw the contact tip back on so that the liner adheres to
it.
- In the free end of the liner, insert the liner nipple and O-
ring, and fasten with the nut without over-tightening.
- Insert the brass tube on the liner and insert the entire unit
in the adapter, after first removing the iron sleeve.
- Cut the liner diagonally so that it is as close as possible to
the wire feeder roller.
- Use wire feeder rollers suitable for aluminium wire.
- Adjust the pressure exerted by the arm of the wire feeder
group on the roller, to the lowest possible setting.
5. WELDING DEFECTS
1 DEFECT -Porosity (within or outside the bead)
CAUSES • Electrode defective (rusted surface)
• Missing shielding gas due to:
- low gas flow
- flow gauge defective
- regulator frosted due to no preheating of
the CO2 protection gas
- defective solenoid valve
- contact tip clogged with spatter
- gas outlet holes clogged
- air drafts in welding area.
2 DEFECT - Shrinkage cracks
CAUSES • Wire or workpiece dirty or rusted.
• Bead too small.
• Bead too concave.
• Bead too deeply penetrated.
3 DEFECT - Side cuts
CAUSES • Welding pass done too quickly
• Low current and high arc voltages.
4 DEFECT - Excessive spraying
CAUSES • Voltage too high.
• Insufficient inductance.
• No preheating of the CO2 protection gas
6. MAINTAINANCE
• Shielding gas nozzle
This nozzle must be periodically cleaned to remove weld
spatter. Replace if distorted or squashed.
• Contact tip.
Only a good contact between this contact tip and the wire can
ensure a stable arc and optimum current output; you must
therefore observe the following precautions:
A) The contact tip hole must be kept free of grime and
oxidation (rust).
B) Weld spatter sticks more easily after long welding sessions,
blocking the wire flow.
The tip must therefore be cleaned more often, and replaced if
necessary.
C) The contact tip must always be firmly screwed onto the
torch body. The thermal cycles to which the torch is subjected
can cause it to loosen, thus heating the torch body and tip and
causing the wire to advance unevenly.
• Wire liner.
This is an important part that must be checked often, because
the wire may deposit copper dust or tiny shavings. Clean it
periodically along with the gas lines, using dry compressed air.
The liners are subjected to constant wear and tear, and
therefore must be replaced after a certain amount of time.
• Gearmotor group.
Periodically clean the set of feeder rollers, to remove any rust
or metal residue left by the coils. You must periodically check
the entire wire feeder group: hasp, wire guide rollers, liner and
contact tip.
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