Telwin Supermig 480 Serie Manual De Instrucciones página 8

5.7.2 Synthetic hose for aluminium wires
Carry out operations 1, 2, 3 as given for the steel hose (ignore operations 4, 5, 6, 7, 8).
9- Re-tighten the contact tip for aluminium, making sure it comes into contact with the
hose.
10-At the other end of the hose (torch connector end) insert the brass nipple and the OR
ring and, keeping slight pressure on the hose, tighten the hose locking nut.
Extract the capillary pipe for steel hoses from the wire feeder torch connector.
11-THE CAPILLARY PIPE IS NOT REQUIRED for aluminium hoses of diameter 1.6-
2.4mm (coloured yellow); the hose is therefore inserted into the torch connector
without it.
Cut the capillary pipe for aluminium hoses of diameter 1.2-1.6mm (coloured red) to
approx. 2mm shorter than the steel pipe, and insert it into the free end of the hose.
12-Insert and lock the torch into the wire feeder connector, mark the hose at 1-2mm
from the rollers, take the torch out again.
13-Cut the hose to the required size, without distorting the inlet hole.
Reassemble the torch in the wire feeder connector and assemble the gas nozzle.
6. WELDING: DESCRIPTION OF THE PROCEDURE
6.1 METHODS OF METAL TRANSFER
6.1.1 Short arc
The melting of the electrode wire and the detachment of the drop is produced by
repeated short circuits (up to 200 times per second) from the tip of the wire to the molten
pool.
Carbon and mild steels
- Suitable wire diameter:
- Welding current range:
- Arc voltage range:
- Suitable gases:
Stainless steels
- Suitable wire diameter:
- Welding current range:
- Arc voltage range:
- Suitable gases:
Aluminium and alloys
- Suitable wire diameter:
- Welding current range:
- Arc voltage range:
- Suitable gases:
- Wire stick out:
Generally, the contact tip should be flush with the nozzle or protrude slightly when
using the thinnest wires and lowest arc voltages; the length of free wire (stick-out) will
normally be between 5 and 12mm. Select the minimum reactance outlet for carbon or
mild steels with C0 gas (wire diameters 0.8-1.2mm) and
2
with Ar/CO gas, high for stainless steel and aluminium.
2
Application: Welding in all positions, on thin material or for the first passage in bevelled
edges, with the advantage of limited heat transfer and highly controllable pool.
Note: SHORT ARC transfer for welding aluminium and alloys should be used with great
care (especially with wires of diameter >1mm) because the risk of melting defects may
arise.
6.1.2 Spray arc
Higher voltages and currents than for "short arc" are used here to achieve the melting of
the wire. The wire tip does not come into contact with the molten pool; an arc forms from
the tip and through it flows a stream of metallic droplets. These are produeced by the
continuous melting of the electrode wire without short-circuits involved.
Carbon and mild steels
- Suitable wire diameter:
- Welding current range:
- Arc voltage range :
- Suitable gases :
Stainless steels
- Suitable wire diameter:
- Welding current range:
- Welding voltage range :
- Suitable gases :
Aluminium and alloys
- Suitable wire diameter:
- Welding current range:
- welding voltage range :
- suitable gases :
The contact tip should generally be 5-10mm inside the nozzle, the higher the arc
voltage the further inside; the length of free wire (stick-out) should normally be between
10 and 12mm. Use the minimum reactance outlet.
Application: Horizontal welding with thicknesses of at least 3-4mm (very fluid pool);
execution rate and deposit rate are very high (high heat transfer).
6.2 ADJUSTING THE WELDING PARAMETERS
6.2.1 Shielding gas
shielding gas flow rate should be:
short arc: 8-14 l/min
spray arc: 12-20 l/min
depending on welding current intensity and nozzle diameter.
6.2.2 Welding current (FIG. L)
Is determined for a given wire diameter by its own advancement speed. Remember that
for a given current the wire advancement speed is inversely proportional to the diameter
used.
Approximate values for the current in manual welding mode for the most commonly
used wires are given in the table (TAB. 4).
0.6-1.2mm
40-210A
13-23V
CO , mix Ar/CO , Ar/CO /O
2 2 2 2
0.8-1mm
40-160A
14-20V
mix Ar/O , Ar/CO (1-2%)
2 2
0.8-1.6mm
75-160A
16-22V
Ar 99.9%
5-12mm
average for the same material
0.8-1.6mm
180-450A
24-40V
mix Ar/CO , Ar/CO /O
2 2 2
1-1.6mm
140-390A
22-32V
mix Ar/O , Ar/CO (1-2%)
2 2
0.8-1.6mm
120-360A
24-30V
Ar 99.9%
- 8 -
6.2.3 Arc voltage
Can be adjusted at short intervals (steps) by switches on the power source. Voltage
must comply with the chosen speed of wire advancement (current), and with the wire
diameter and shielding gas used. This may be set out in the following equation giving the
medium value:
U = (14 + 0,05 x l )
2 2
where :U = arc voltage in volts;
2
l = welding current in amperes.
2
Remember that in comparison with the no-load voltage supplied for each step, the arc
voltage will be less 2-4V for every 100A delivered. The argon/CO mixtures require arc
voltage of 1-2V less than that required with CO .
6.2.4 Weld quality
The quality of the weld seam is higher when less spatter is produced. this is determined
principally by a correct balance of the welding parameters: current (wire speed), wire
diameter, arc voltage etc., as well as a correct choice of choke intakes.
In the same way the torch position must comply with the data in figure (FIG. M) in order
to avoid excessive spatter and faults on the weld seam. The weld speed (i.e. the
advancement speed along the joint) is also a determining factor for the correct
execution of the seam. This is particularly important for good penetration and correct
shape of the seam.
The most common welding flaws are summarized in TAB.5.
7. MAINTENANCE
_____________________________________________________________________________________________________________________
WARNING! BEFORE CARRYING OUT MAINTENANCE OPERATIONS MAKE
SURE THE WELDING MACHINE IS SWITCHED OFF AND DISCONNECTED FROM
THE MAIN POWER SUPPLY.
_____________________________________________________________________________________________________________________
7.1 ROUTINE MAINTENANCE
ROUTINE MAINTENANCE OPERATIONS CAN BE CARRIED OUT BY THE
OPERATOR.
7.1.1.Torch
- Do not put the torch or its cable on hot pieces; this would cause the insulating
materials to melt, making the torch unusable after a very short time.
- Make regular checks on the gas pipe and connector seals.
- Every time the wire reel is changed, blow out the wire-guide hose using dry
compressed air (max. 5bar) to make sure it is not damaged.
- To control, before every I use, check the wear and correct assembly of the parts at
the end of the torch: nozzle, contact tip, gas diffuser.
7.1.2 Wire feeder
- Make frequent checks on the state of wear of the wire feeder rollers, regularly
remove the metal dust deposited in the feeder area (rollers and wire-guide infeed
and outfeed).
7.2 EXTRAORDINARY MAINTENANCE
EXTRAORDINARY MAINTENANCE OPERATIONS SHOULD BE CARRIED OUT
ONLY AND EXCLUSIVELY BY SKILLED OR AUTHORISED ELECTRICAL-
MECHANICAL TECHNICIANS.
_____________________________________________________________________________________________________________________
WARNING! BEFORE REMOVING THE WELDING MACHINE PANELS AND
WORKING INSIDE THE MACHINE MAKE SURE THE WELDING MACHINE IS
SWITCHED OFF AND DISCONNECTED FROM THE MAIN POWER SUPPLY
OUTLET.
_____________________________________________________________________________________________________________________
If checks are made inside the welding machine while it is live, this may cause
serious electric shock due to direct contact with live parts and/or injury due to
direct contact with moving parts.
- Inspect the welding machine regularly, with a frequency depending on use and the
dustiness of the environment, and remove the dust deposited on the transformer,
reactance and rectifier using a jet of dry compressed air (max. 10bar).
- Do not direct the jet of compressed air on the electronic boards; these can be
cleaned with a very soft brush or suitable solvents.
- At the same time make sure the electrical connections are tight and check the wiring
for damage to the insulation.
- At the end of these operations re-assemble the panels of the welding machine and
screw the fastening screws right down.
- Never, ever carry out welding operations while the welding machine is open.
8. TROUBLESHOOTING
_____________________________________________________________________________________________________________________
WARNING! CARRYING OUT CERTAIN CHECKS IMPLIES THE RISK OF
CONTACT WITH LIVE AND/OR MOVING PARTS.
_____________________________________________________________________________________________________________________
Before carrying out any operation on the wire feeder or inside the welding machine it is
absolutely necessary to refer to section 7 " MAINTENANCE".
2
2
(TAB.6)