Spot Welding; Aluminium Welding; Preparation For Welding - Helvi UNIMIG 298+T2E Manual De Uso

If this lamp lights up, it means that you have to add cooling fluid to the system
21 fast connections.
They are placed on the front of the wire feeder. The torch cooling pipes are connected to these fast
connections.
22 fast connections.
They are placed on the rear of the wire feeder and on the rear of the cooling unit; the interconnection
pipes are connected to these fast connections.
23 Cooling unit power cable.
24 Cable for the connection of the cooling unit safety device (pressure switch).
10.0
Only for models fitted with timer for spot welding.
It is possible to spot weld two sheets of up to 0,8mm thickness mild steel by replacing the torch gas
nozzle with a spot welding nozzle (not supplied). Select the spot welding function by adjusting the timer .
Place two sheets one upon another; place the nozzle on the upper sheet and then press the torch trigger
ensuring that the sheets are in contact. Press the trigger to spot weld the first sheet to the second one. The
spot welding will automatically stop when the adjusted time has passed. For spot welding, the machine
must be set at maximum current and maximum wire speed. It is advisable to use 0,8mm ø wire.
11.0
The machine will be set up as for mild steel except for the following changes:
• 100% ARGON as welding protective gas.
• Ensure that your torch is set up for aluminium welding:
1. The lenght of the torch cable should not exceed 3m (it is advisable not to use longer torches).
2. Install a teflon wire liner (follow the instructions for the renewing of the wire liner at paragraph 8).
3. Ensure that drive rolls are suitable for aluminium wire.
• Use contact tips that are suitable for aluminium wire and make sure that the diameter of the con-
tact tip hole corresponds to the wire diameter that is going to be used.
12.0
WARNING: make sure the polarity is correctly set. for GAS welding the torch must be
connected to the positive terminal (+), while the ground cable must be connected to the
negative terminal (-).
for NO GAS welding the torch must be connected to the negative terminal (-), while the
ground cable must be connected to the positive terminal (+).
In GAS welding, to avoid the oxidation of the weld puddle, we need a shielding gas. In
NO GAS welding the protection is given by the flux cored wire.
• Connect the ground cable to the proper
female outlet on the bottom right-hand
corner of the welder (on some models the
ground cable is already connected).
• Attach the ground clamp to the bare metal
to be welded, making sure of good con-
tact;
• Make sure that the wire-roller groove in the
roller corresponds to the diameter of the
wire being used. Refer to paragraph 7.
• Plug the machine to a suitable outlet.
• Open the gas valve on the gas cylinder re-
gulator, (turn knob counter-clockwise) and
adjust the flow rate using the regulator
knob (turn it counter-clock wise to decrea-
se the gas flow; turn it clockwise to increa-
se the gas flow). Note: The gas flow may need adjustments in order to obtain a better welding,
this depends on the type and thickness of the metal and on the welding current.

SPOT wELDINg

ALUMINIUM wELDINg

PREPARATION fOR wELDINg

-ENGLISH-
GAS
NO GAS
FIG. 20
35