Telwin MASTERMIG 500 R.A. [6/80] Welding description of the procedure

- Turn the switch to <TIMER> position.

- Insert the welding machine plug in the power supply outlet, switch on the welding - Set the time at 1-1.5 seconds

machine, press the torch button and wait for the end of the wire to pass through the A spot of welding will therefore be carried out at the point where the head of the rivet is

whole of the wire guide hose and protrude by 10-15 cm from the front part of the located and so joining the latter to the metal sheet. The dented metal sheet can now be

torch, release the button. re-shaped using the appropriate appliance

___________________________________________________________________

6.6 METAL SHEET HARDENING (FIG.M)

This operation is only possible for compact welding machines with one or more earth

WARNING! During these operations the wire is live and subject to mechanical

___________________________________________________________________

original state. This torch is used to heat the metal sheet up to about 800° Celsius and is

then rapidly cooled using a cloth soaked with water.

- Do not direct the mouthpiece of the torch towards parts of the body.

The oxyacetylene equipment can now be replaced using the following hardening

- Keep the torch away from the gas bottle.

process:

- Re-fit the contact tip and the nozzle onto the torch (4b).

- Remove the torch nozzle and fit the special electrode holder and the coal electrode by

- Check that wire feed is regular; set the roller and spindle braking pressure to the

- Release the pressure from the towing rollers by releasing the spring in order to

- Close the reel compartment door.

prevent the wire from being dragged along the torch.

If only a small area is to be hardened, carry out the operation as if it were spot welding by

6. WELDING: DESCRIPTION OF THE PROCEDURE

placing the end of the electrode in contact with the metal sheet until this heats up. When

6.1 PRELIMINARY OPERATIONS

the sheet is sufficiently heated, cool it down using a cloth soaked with water. If a large

- Insert the earth connector into the (-) socket (for welding machines with a single earth

area is to be hardened, the electrode should be rotated.

- The indicator light comes on when there is overheating and cuts off the power supply;

material and resulting (Al) alloys, copper alloys (CuAl/CuSi).

it will reset automatically within a few minutes, after cooling down.

- quick connector (-) with min reactance ( ) or position 1-2 for stainless steel

___________________________________________________________________

(SS), carbon steel and low-alloy (Fe) steel.

- Connect the return cable to the piece being welded.

- Turn on and adjust the protective gas using the pressure reducing valve (5-7 l/min)

7. MAINTENANCE

NOTE: At the end of the job, remember to turn off the protective gas.

THE MAIN POWER SUPPLY.

Once the machine has been prepared for welding by carrying out the operations

___________________________________________________________________

described above, simply place the earth clamp in contact with the workpiece and press

the torch button, keeping the torch at a safe distance from the workpiece.

7.1 ROUTINE MAINTENANCE:

Before carrying out difficult sections of welding, tests should be carried out on scrap

ROUTINE MAINTENANCE OPERATIONS CAN BE CARRIED OUT BY THE

pieces. These tests should be carried out using the adjustment knob in order to obtain

OPERATOR.

suited to a specific current and wire feed speed. Therefore, for difficult sections of

- Make regular checks on the gas pipe and connector seals;

welding and welding which requires a great deal of time, wires with different diameters

- Every time the wire reel is changed, blow out the wire-guide hose using dry

should be tried so that the most suitable may be chosen.

- Before using the welding machine, always check the torch terminal parts for wear

6.3 ALUMINIUM WELDING

Aluminium MIG welding does not present any particular problems. The only difficulty is

in the pulling of the wire for the whole length of the torch, since aluminium is known to

have poor mechanical characteristics. The smaller the diameter of the wire the more this

7.2 EXTRAORDINARY MAINTENANCE

problem is accentuated.

EXTRAORDINARY MAINTENANCE OPERATIONS SHOULD BE CARRIED OUT

This problem can be avoided by making the following changes:

ONLY AND EXCLUSIVELY BY SKILLED OR AUTHORISED ELECTRICAL-

4- Replace the steel guide hose for wire feed with a Teflon guide hose.

WORKING INSIDE THE MACHINE MAKE SURE THE WELDING MACHINE IS

The above pieces for aluminium welding are available as optionals.

SWITCHED OFF AND DISCONNECTED FROM THE MAIN POWER SUPPLY

OUTLET.

6.4 SPOT WELDING (FIG.I)

___________________________________________________________________

Two overlapping metal sheets can be spot-welded together using a wire system and

If checks are made inside the welding machine while it is live, this may cause

- Inspect the welding machine regularly, with a frequency depending on use and the

In order to use the machine for spot-welding, it should be set-up as follows:

- Replace the nozzle of the torch with the nozzle required for spot-welding, which is

- Do not direct the jet of compressed air on the electronic boards; these can be cleaned

- Turn the current adjustment switch to <maximum> position.

To carry out the spot welding, rest the nozzle of the torch on the surface of the first metal

- Never, ever carry out welding operations while the welding machine is open.

sheet, then press the torch button in order to start welding: the wire will melt the first

sheet, pass through this sheet and into the second, making a molten wedge between

the two metal sheets.

The button should be pressed until the timer interrupts the welding.

This system allows spot-welding to be carried out which would not normally be possible

with conventional spot-welders, since metal sheets can be joined which do not allow

access to the rear side such as box-type sheets.