PATON
VDI-SERIES PRO
DC MMA/TIG/MIG/MAG
-18-
3.9. WELDING AT PULSE WELDING CURRENT
This function is designed to simplify the control of a welding process in various spatial
welding positions, excluding a flat welding position. This function is also used in welding
nonferrous metals. When this function is activated, the application of pulse welding
current improves the mixing of molten metals in the weld area and causes forced action
on the transfer of molten metal drops into the welding pool, therefore the stability of the
weld formation and the stability of the welding process are improved. The pulse welding
current in the manual arc welding process affects the weld parameters similar to the
movement of the operator hand in manual arc welding process, specifically at hard-to-
reach places. The proper adjustment of the welding process parameters in the welding at
pulse welding current has a direct effect on the weld quality, specifically reduces weld
metal porosity and decreases the graininess of the weld metal. As a result of the improved
weld quality, the weld strength increases.
To activate this function, it is necessary to set the following three operational parameters
of the welding process: current pulse amplitude
[Po.P]
, current pulse frequency
[Fr.P]
,
and duty cycle
[dut].
By default, the current pulse amplitude is 0
[OFF],
that is, the
function is switched off, the current pulse frequency is 50 Hz, and the duty cycle is 50 %.
To activate the function, set the current pulse amplitude
[Po.P]
higher than 0. The current
pulse amplitude should be set in percentage of the welding current specified for the
welding process.
Example:
Welding is to be performed with electrode wire 3.0 mm in diameter.
The set welding current is 90 A.
The current pulse amplitude is 40 %.
The current pulse frequency is 50 Hz (default value).
The duty cycle is 50 % (default value).
The result is the following: the welding current pulse amplitude will be in the range of
54 … 126 A, the current pulse frequency will be 50 Hz, and the current pulse length will
be equal to the length of an interval between pulses. If the duty cycle is not equal to
50 %, the current pulses will be nonsymmetrical relative to the intervals between pulses,
but the average welding current value will be equal to the set welding current value of
90 A. As a result, the average heat input to the weld will not change.
If it is required to reduce heat input to the weld, as in welding thin parts, the welding
current should be decreased by performing the standard setting operations. In this case,
current pulse parameters will be adjusted automatically according to the set welding
current, and the operator can control the reduction of the heat input, as compared with the
heat input at the initial welding current, by simultaneously varying the current pulse
amplitude and duty cycle.
The aforementioned parameters should be set differently for different welding processes,
depending on the requirements of the operator.
Operations required to set these parameters for the current welding process are described in Section
6.1
.
