Telwin 954056 Manuel D'instructions page 8

- Insert the control cable connector into the relative socket.
The compressed air vents do not have to be connected.
6. WELDING (Spot welding)
6.1 PRELIMINARY OPERATIONS
Before carrying out any spot welding operation, a series of checks and adjustments
must be made with the main switch at "O" and the padlock closed.
- Make sure the electrical connection has been carried out correctly as indicated in
the previous instructions.
- Check the compressed air connection; connect the supply hose to the pneumatic
network, adjust the pressure using the reduction knob until a value of between 4
and 8 bar (60 - 120 psi), according to the thickness of the plate to be spot welded,
can be read on the gauge.
- Place a shim of the same thickness between the electrodes; make sure the arms,
which have manually been brought closer, are parallel and the electrodes are
aligned (coinciding tips).
Adjust if necessary, by loosening the locking screws of the arms that can be rotated
or moved in both directions along their axis; after adjusting, carefully tighten the
locking screws.
- The work stroke can be adjusted using the electrodes. Always remember that a
stroke that is 6-8 mm longer than the spot welding position is necessary, to exercise
the required force on the workpiece.
FIG. G shows a "standard" adjustment of the electrode position with clamp resting.
- Using the manual clamp, consider that the power of the electrodes during the spot
welding phase can be adjusted with the knurled nut (FIG. H); turn it clockwise (to
the right) to increase the force proportional to the increase in the sheet thickness,
selecting adjustments that make it possible to close the clamp (and relative micro
switch activation) using very limited power. The correct position of the arms and
electrodes is the same as that of the pneumatic clamp.
6.2 PARAMETER ADJUSTMENT (in spot welding)
The parameters that determine the diameter (section) and mechanical seal of the
spot are:
- Force at the electrode.
- Spot welding current.
- Spot welding time.
If there is no specific experience, it is a good idea to carry out some spot welding tests
using sheets of the same quality and thickness as those to be worked on.
Adjust the electrode power using the pressure adjusters ad indicated in 6.1, selecting
medium-high values.
The current and spot welding time parameters are adjusted automatically by selecting
the thickness of the sheet to be welded with the (+ / - icons) keys. Adjustments can
be made to the standard spot time (DEFAULT), within set limits, using the key (icon
fig. C-2).
Insert the pulse, having to spot weld sheets of thickness 0.8-1.2 mm at a high
yield point.
The pulse period is automatic, and as such does not need to be adjusted.
IMPORTANT: If the selected thickness "flashes", this means that the default
initially programmed spot welding current is insufficient for spot welding in a satisfactory
manner; compatibly with the power available in the installation area, reprogram the
spot welding machine at maximum current (see paragraph 4.2.1): high spot welding
currents combined with reduced times give better spot characteristics.
The spot is considered as correct when the nugget of the weld point can be extracted
from one of the two sheets when tension is tested.
6.3 PROCEDURE
6.3.1 PNEUMATIC CLAMP
- The squeeze time is automatic; the value varies according to the selected sheet
thickness.
- Place an electrode on the surface of one of the two sheets to be spot welded.
- Press the push-button on the clamp handle to:
a) Close the sheets between the electrodes with the pre-adjusted force (cylinder
movement).
b) Pass the set welding current for the set time, signalled by the
switches on and off.
- Release the push-button a few moments after the icon has switched off (end of
welding); this delay (maintenance) gives the weld better mechanical characteristics.
6.3.2 MANUAL CLAMPS
- Place the lower electrode on the sheets to be spot welded.
- Move the upper lever of the clamp to the end stop to:
a) Close the sheets between the electrodes with the pre-adjusted force.
b) Pass the set welding current for the set time, signalled by the
switches on and off.
- Release the clamp lever a few moments after the icon has switched off (end of
welding); this delay (maintenance) gives the weld better mechanical characteristics.
6.3.3 STUDDER GUN
ATTENTION!
- To fix or remove the tools from the gun spindle, use two hex keys in a manner
that stops the spindle from rotating.
- If working on doors or hoods, connect the earth bar to them to prevent
current from passing through the hinges, and near the area to be spot welded
(long current runs reduce spot efficiency).
6.3.4 Earth cable connection
a) Bare the sheet as close as possible to the working area, for a surface that
corresponds to the earth bar contact surface.
b1) Fix the copper bar to the sheet surface, using a JOINTED CLAMP (welding
model).
As an alternative to method "b1" (difficult t carry out):
b2) Spot weld a washer to the previously prepared sheet surface; pass the washer
through the slit in the copper bar and lock it in position with the supplied clamp.
Washer welding for mass terminal fixing
Mount the relative electrode (POS. 9, Fig. I) in the gun spindle, and insert the washer
(POS. 13, Fig. I).
Place the washer in the selected area. Place the earth terminal in contact in the
same area; press the gun push-button to weld the washer, which should be fixed as
indicated previously.
Screw, washer, nail, rivet spot welding
Fit the most suitable electrode on the gun, insert the element to be spot welded and
place it on the sheet in the necessary spot; press the gun push-button: release the
push-button only after the set time has elapsed.
Spot welding sheets on one side only
Fit the most suitable electrode on the spindle (POS. 6, Fig. I), pressing on the surface
to be spot welded. Activate the gun push-button, release the push-button only after the
set time has elapsed.
ATTENTION!
Maximum thickness of the plate that can be spot welded, on only one side: 1+1
mm. This type of spot welding cannot be used on the supporting frames of the
chassis.
To obtain correct results when sport welding sheets, some fundamental precautions
must be taken:
1 - An impeccable earth connection.
2 - Any paint, grease, oil must be cleaned from the two parts to be spot welded.
3 - The parts to be spot welded must be in contact with each other, without gaps;
if necessary press with a tool, not with the gun. Excessive pressure brings bad
results.
4 - The upper piece must not be thicker than 1 mm.
5 - The electrode tip must have a diameter of 2.5 mm.
6 - Tighten the nut that locks the electrode well, make sure the welding cable
connectors are locked.
7 - When spot welding, position the electrode and push it slightly (3-4 kg). Press the
push-button and allow the spot welding time to elapse, and only then remove the
gun.
8 - Never distance yourself further than 30 cm from the earth fixing point.
Contemporaneous spot welding and drawing of special washers
This function can be carried out by assembling and fully tightening the spindle (POS.
4, Fig. I) on the body of the extractor (POS. 1, Fig. I): hook and fully fasten the other
end of the extractor on the gun. Insert the special washer (POS. 14, Fig. I) into the
spindle (POS. 4, Fig. I), and lock it with the relative screw (Fig. I). Spot weld in the
relative area, adjusting the spot welding machine as if spot welding washers, and start
drawing.
At the end, rotate the extractor by 90° to release the washer, which can be spot welded
in a new position.
Sheet heating and upsetting
or
In this mode the TIMER is disabled.
Operation duration is therefore manual, being determined by the time in which the gun
push-button is kept pressed.
Current intensity is adjusted automatically according to the thickness of the selected
sheet.
Fit the carbon electrode (POS. 12, FIG, I) into the gun spindle, locking it with the ring
nut. Touch the area, that was previously bared, with the carbon tip and press the gun
push-button. Work from the outside to the inside, using a circular movement to heat
the sheet which undergoes work hardening and returns to its original position.
To prevent the sheet from drawing too much, treat small areas and immediately after
wipe using a damp cloth to cool the treated part.
Sheet upsetting
From this position operate on the relative electrode to flatten sheets that have localized
deformations.
icon that
Intermittent spot welding
This function is suitable for spot welding small rectangles of sheet in order to cover
holes caused by rust or other reasons.
Place the relative electrode (POS. 5, Fig. I) on the spindle, accurately tighten the ring
nut. Bare the involved area and make sure the piece of sheet to be spot welded is
clean and free from grease or paint.
Position the workpiece and place the electrode against it, then press the gun push-
button. Keeping it constantly pressed move forward rhythmically, following the work/
pause intervals given by the spot welding machine.
N.B.: Press lightly while working (3-4 kg), following a line that is ideally 2-3 mm from
icon that the edge of the new piece to be welded.
To obtain good results:
1 - Remain within 30 cm from the earth fixing point.
2 - Use cover sheets that are no more than 0.8 mm thick, better if of stainless steel.
3 - Move forward in time with the spot welding machine rhythm. Move forward during
the pause moments, and stop while spot welding.
Using the supplied extractor (POS. 1, Fig. I)
Washer hooking and drawing
This function is carried out by assembling and tightening the spindle (POS. 3, Fig.
I) onto the body of the electrode (POS. 1, Fig. I). Hook the washer (POS. 13, Fig. I),
spot welded as described previously, and begin drawing. When finished, rotate the
extractor by 90° to detach the washer.
Plug hooking and drawing
This function is carried out by assembling and tightening the spindle (POS. 2, Fig. I)
onto the body of the electrode (POS. 1, Fig. I). Make the plug enter (POS. 15-16, Fig.
I), after spot welding it as described previously, the spindle (POS. 1, Fig. I) keeping the
terminal tightened towards the extractor (POS. 2, Fig. I). When completely introduced,
release the spindle and start drawing. When finished, pull the spindle towards the
hammer to remove the plug.
STUDDER TOUCH
The studder can be supplied in the version without push-button.
To spot weld, just place the tool against the piece to be welded, which is connected to
the earth cable: after a few moments, the machine recognises the contact and starts
the stop automatically.
ATTENTION: DO NOT PLACE THE STUDDER ON THE PIECE WITHOUT
WELDING!
- 8 -