- 10 -
spray arc and pulse arc:
12-20 l/min
depending on welding current intensity and nozzle diameter.
6.1.4.2 Welding current
Welding current is adjusted by the operator by turning the encoder knob
(FIG.E
(14))
. When SPRAY/SHORT ARC is selected, each turn of the encoder knob
(14)
corresponds to a wire feed rate adjustment (m/minute), which is shown on the display
(16)
; during welding, the display automatically switches to the actual current value
(amps).
When PULSE ARC or
PULSE ARC PULSE-ON-PULSE
is selected, each time the
encoder knob
(14)
is turned this corresponds to an adjustment of welding current,
which is shown on the display
(16)
; during welding, the display automatically switches
to the actual current value.
In both modes it is possible to press key (17) to pass to regulation of thickness in mm
(LED (16b) lit up) using the encoder (14). The machine automatically calculates the
current required to weld this thickness. Also in this case the display will switch to the
actual current (amps.) during welding.
It should be pointed out that in all the synergic programs the maximum and minimum
values for the settings (m/minute, amps or thickness in mm) are programmed in the
factory and cannot be changed by the user.
Indicative values for the current with the most commonly used wires are given in the
table
(TAB.5)
.
6.1.4.3 Arc voltage and arc pinch-off
In the MIG-MAG pulse-arc and pulse-on-pulse synergic programmes these two
parameters determine the arc size
during welding.
Arc voltage indicates the distance of the wire from the piece, the operator is allowed
to make a simple correction between -5% and +5% of the preset voltage value in
each programme, if it is necessary to adjust the actual arc length under specific
circumstances. The higher the value the further the wire from the piece.
Arc pinch-off, on the other hand, determines arc concentration or amplitude. The
adjustment range for this parameter is from -10% to +10% of the default value for the
programme. The higher the value the more concentrated will be the arc.
In manual programming ”PRG 0” arc voltage is defined by setting a suitable value for
the selected wire feed rate, according to the following relationship:
U
2
= ( 14+0.05 I
2
) where:
- U
2
= Arc voltage in volts
- I
2
= Welding current in amps.
Bear in mind that the selected loadless voltage will correspond to a voltage under load
(during welding) that is 2-4V lower.
6.1.5 BI-LEVEL AND PULSE ON PULSE OPERATION
The bi-level operation setting is made using key (8) and can be selected in MIG-MAG
pulse arc and short arc modes. The welding cycle starts by pressing and releasing
the torch button (as for 4-stroke), the initial working point for the welding machine is
the main welding level (LED (10a)), the machine displays the current and voltage for
this working point. If the torch button is pressed for less than 0.5 seconds the machine
will change the working point from the main level to the secondary level (LED 10(b)),
and will display the current and voltage of the secondary level. Every time the button
is pressed the machine will continue to pass from one level to the other until the
button is pressed for more than 0.5 seconds, Even though the machine displays the
instantaneous value of current and voltage during welding, it is only possible to change
the current and voltage of the main welding level.
MIG-MAG Pulse on Pulse
operation is activated by key (7) with the MIG-MAG Pulse
arc LED. This mode is a special type of bi-level because also in this case two working
points can be set with the same criteria as bi-level (LED’s (10a) and (10b)). It is
possible to set the time in each level, t
1
and t
2
(LED’s (10c) and (10d)) and they are not
decided manually as for bi-level. During welding the machine therefore automatically
continues to change the working point from the main level (time t
1
) to the secondary
level (time t
2
).
This leads to the creation of a pulse within the pulse, from which the name is derived.
If the two levels and times are set correctly it is possible to obtain a ”rippled bead” weld
that strongly resembles TIG welding.
6.2 TIG (DC) WELDING
After making the welding circuit connections as described in section 5.5.2. proceed
as follows:
- Select the TIG welding procedure on the welding machine control panel
(FIG.C (7))
.
- Set the welding current to the desired value using the encoder knob (14) (the value
can always be adjusted during welding as well). If necessary insert the current
downslope using the potentiometer (13) (indicated momentarily on the display (16)).
6.2.1 LIFT strike
Place the tip of the electrode on the piece, using slight pressure. Press the torch button
right down and lift the electrode by 2-3 mm with a slight delay, so that the arc strikes.
The welding machine will first output a base current I
BASE
, after a few moments the
current output will be equal to the welding current setting. At the end of the cycle the
current will decrease according to the slope down setting.
The table
(TAB. 5)
summarises some indicative data for welding stainless or high
alloy steel.
6.3 MMA WELDING WITH COATED ELECTRODES
After making the welding circuit connections as described in section 5.5.3 select the
MMA procedure using the corresponding button
(FIG. C (7))
:
The welding current should be adjusted to the desired value using encoder knob (14)
and if there is an “ARC FORCE” dynamic overcurrent it can be varied between 0 and
100% using encoder knob (13), with a momentary indication shown on the display
(16).
The table
(TAB. 6)
summarises some indicative values for the current in relation to
electrode diameter.
6.4 WELD QUALITY
The quality of the weld seam, and the amount of spatter, is mainly determined by the
balance of the welding parameters: current (wire feed rate), wire diameter, arc voltage
etc.
In addition, the position of the torch should be adjusted as shown in
Fig. M
, to prevent
excessive spray production and flaws in the seam.
The welding rate (i.e. advancement speed along the join) should also be taken into
consideration. This is a determining factor for correct penetration and for the shape
of the seam itself.
The most common welding flaws are summarised in the table (
TAB. 7).
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.
- At least once a day, 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 MUST ONLY BE CARRIED OUT BY
TECHNICIANS WHO ARE EXPERT OR QUALIFIED IN THE ELECTRIC-
MECHANICAL FIELD, AND IN FULL RESPECT OF THE IEC/EN 60974-4
TECHNICAL DIRECTIVE.
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.
- Periodically, and in any case with a frequency in keeping with the utilisation and with
the environment’s dust conditions, inspect the inside of the welding machine and
remove the dust deposited on the electronic boards with a very soft brush or with
appropriate 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.
- After having carried out maintenance or repairs, restore the connections and wiring
as they were before, making sure they do not come into contact with moving parts or
parts that can reach high temperatures. Tie all the wires as they were before, being
careful to keep the high voltage connections of the primary transformer separate
from the low voltage ones of the secondary transformer.
Use all the original washers and screws when closing the casing.
8. TROUBLESHOOTING (TAB.8)
WARNING! CARRYING OUT CERTAIN CHECKS IMPLIES THE RISK OF
CONTACT WITH LIVE AND/OR MOVING PARTS.
IF THE WELDING MACHINE IS NOT WORKING PROPERLY, BEFORE MAKING
MORE SYSTEMATIC CHECKS OR CALLING YOUR SERVICING CENTRE MAKE
THE FOLLOWING CHECKS:
- Make sure the welding current (adjusted using the encoder) is correct.
- Make sure there is no alarm indicating triggering of the thermal relay or of the
overvoltage, undervoltage or short circuit safeguards.
- Make sure you have not exceeded the rated duty cycle; if the thermal cutout has
triggered wait until the welding machine has cooled naturally, make sure the fan is
working properly.
- Check the main power supply voltage: if it is too low or too high the welding machine
will signal this fault (see section 4.2).
- Make sure there is no shorting at welding machine output: in such a case eliminate
the problem.
- Make sure the welding circuit connections have been made correctly, in particular
that the earth clamp is actually connected to the piece, with no insulating material
(e.g. paint) in the way .
- Make sure you are using the right protective gas, and the correct amount.
Before carrying out any work on the wire feeder or inside the welding machine, first
consult chapter 7 on “
MAINTENANCE”.
