Scheppach WSE4000-Multi Original Bedienungsanleitung Seite 33

c. Insert the appropriate welding wire and open the
pressure valve (11) on the back of the device.
3 Connect the mains cable and activate the power
supply. After connecting the earth cable, the
welding process can be started.
MIG welding
• Connect the earth clamp (5) to the workpiece to
be welded. Make sure that there is good electrical
contact.
• Rust and paint must be removed from the workpiece
at the welding point.
• Select the desired welding current to suit the welding
wire diameter, the material thickness and the desired
penetration depth.
• Guide the torch nozzle (7) to the place on the
workpiece where welding is to be done and hold the
welding shield in front of the face.
• Press the burner button (9) to feed the welding wire.
Once the arc is lit, the device feeds welding wire into
the weld pool.
• The optimum setting of the welding current can be
determined by trial and error on a test piece. A well
adjusted electric arc creates a soft, even buzzing
sound.
• If there is a rough or hard crackling sound, switch
to a higher power level (increase welding current).
• If the spot is large enough, guide the burner (8) slowly
along the desired edge. The distance between the
burner nozzle and the workpiece should be kept as
short as possible (never larger than 10 mm).
• If necessary, swing the burner nozzle slightly in
order to enlarge the weld pool a little. For those with
little experience, the initial difficulty lies in creating a
stable electric arc. The welding current must be set
correctly for this.
• The penetration depth (corresponds to the depth of
the weld seam in the material) should be as deep as
possible but the weld pool should not drop through
the workpiece.
• If the welding current is too low, the welding wire
cannot melt properly. As a result, the welding wire
repeatedly dips into the weld pool right down to the
workpiece.
• The slag should only be removed from the seam
once it has cooled. To continue a weld on an
interrupted seam:
• First remove the slag at the attachment point.
• The electric arc is struck in the weld groove, guided
to the connection point, properly melted there and
then continued along the weld seam
Creating a weld seam
Forward-pointing welding or butt welding
The burner is pushed forward. Result: The penetration
depth is smaller, seam width larger, seam top bead
(visible surface of the weld) flatter and the fusion fault
tolerance (defect in material melting) larger.
Drag weld seam or draw welding
The torch is pulled away from the weld. Result: The
penetration depth is greater, the seam width smaller,
the seam top bead higher and the fusion fault tolerance
smaller.
Welded joints
There are two basic types of connection in welding
technology:
Butt joint (outside corner) and fillet joint (inside corner
and overlap).
Butt weld joints
For butt joints up to 2 mm material thickness, the
weld edges are brought completely together. For
larger thicknesses, a distance of 0.5 - 4 mm should
be chosen. The ideal spacing depends on the welded
material (aluminium or steel), the material composition
and the selected welding method.
This distance should be determined on a test piece.
Flat butt weld joints
Welds should be carried out without interruption and
with sufficient penetration, so good preparation is
extremely important. The quality of the resultant weld
is influenced by: the current intensity, the distance
between the welding edges, the inclination of the torch
and the diameter of the welding wire. The steeper the
torch is held in relation to the workpiece, the higher the
penetration depth and vice versa.
Fillet weld joints
A fillet weld is created when the workpieces are
perpendicular to each other. The seam should have
the shape of a triangle with sides of equal length and
a slight valley.
Overlapping weld joints
The most common preparation is the one with straight
welding edges. The weld can be resolved with a normal
angled weld. The two workpieces must be brought as
close together as possible.
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