CIGWELD weldskill 100, Operating Manual, Page: 43 / 60

weldskill 100, 135, 150 MiG
4-7
Operation
3. Nozzle Angle. This refers to the position of
the welding gun in relation to the joint. The
transverse angle is usually one half the in-
cluded angle between plates forming the joint.
The longitudinal angle is the angle between
the centre line of the welding gun and a line
perpendicular to the axis of the weld. The lon-
gitudinal angle is generally called the Nozzle
Angle and can be either trailing (pulling) or
leading (pushing). Whether the operator is left
handed or right handed has to be considered
to realize the effects of each angle in relation
to the direction of travel.
Transverse and Longitudinal
Nozzle Axes
Art # A-08998_AB
Longitudinal
Angle
Axis of Weld
Transverse
Angle
Figure 4-13
Art # A-08999_AC
Nozzle Angle, Right Handed Operator
Direction of Gun Travel
Leading or “Pushing”
Angle
(Forward Pointing)
Trailing or “Pulling”
Angle
(Backward Pointing)
90°
Figure 4-14
establishing the Arc and Making weld Beads
Before attempting to weld on a finished piece of work,
it is recommended that practice welds be made on
a sample metal of the same material as that of the
finished piece.
The easiest welding procedure for the beginner to
experiment with MIG welding is the flat position. The
equipment is capable of flat, vertical and overhead
positions.
For practicing MIG welding, secure some pieces
of 16 or 18 gauge (0.06” 1.5mm or 0.08” 2.0mm)
mild steel plate 6” x 6” (150 x 150mm). Use 0.024”
(0.8mm) flux cored gasless wire or a solid wire with
shielding gas.
setting of the Power source
Power source and Wirefeeder setting requires some
practice by the operator, as the welding plant has two
control settings that have to balance. These are the
Wirespeed control and the welding Voltage Control.
The welding current is determined by the Wirespeed
control, the current will increase with increased Wire-
speed, resulting in a shorter arc. Less wire speed will
reduce the current and lengthen the arc. Increasing
the welding voltage hardly alters the current level, but
lengthens the arc. By decreasing the voltage, a shorter
arc is obtained with a little change in current level.
When changing to a different electrode wire diameter,
different control settings are required. A thinner
electrode wire needs more Wirespeed to achieve the
same current level.
A satisfactory weld cannot be obtained if the Wire-
speed and Voltage settings are not adjusted to suit
the electrode wire diameter and the dimensions of
the work piece.
If the Wirespeed is too high for the welding voltage,
“stubbing” will occur as the wire dips into the molten
pool and does not melt. Welding in these conditions
normally produces a poor weld due to lack of fusion.
If, however, the welding voltage is too high, large
drops will form on the end of the wire, causing spatter.
The correct setting of voltage and Wirespeed can be
seen in the shape of the weld deposit and heard by a
smooth regular arc sound.
electrode wire size selection
The choice of Electrode wire size and shielding gas
used depends on the following
• Thickness of the metal to be welded
• Type of joint
• Capacity of the wire feed unit and Power
Source
• The amount of penetration required
• The deposition rate required
• The bead profile desired
• The position of welding
• Cost of the wire