Lincoln Electric IM542-D manual Overview of Welding Procedures, Pulse Procedures, Wave Control

B-16 B-16

OPERATION

OVERVIEW OF WELDING

PROCEDURES

FLUX CORED ARC WELDING (FCAW) AND GMAW PROCEDURES

For each wire feed speed, a corresponding voltage is preprogrammed into the machine by welding experts. This preprogrammed voltage is the best average volt- age for the procedure at the given wire feed speed. If the wire feed speed is changed on the wire feeder, the voltage automatically changes with it.

In some cases, the operator may want to change the preprogrammed voltages; for example, to compensate for cable and fixture voltage drops. The preset voltages can be adjusted on the wire feeder’s Voltage display. When a change is made to the voltage at one wire feed speed, this change is applied to all other wire feed speed settings. For example, if the operator turns up the voltage by 10 percent, the machine automatically increases the preset voltages at all the other wire feed speeds by 10 percent. In the GMAW and FCAW process, the display shows The Procedure Description, WFS and Preset Voltage. The preset voltage which was pro-grammed at the factory, may be changed on the wire feeder voltage display. Note that if you change the

default preset voltage up or down a respective “ ” or “ ” V sign will be dis-played after the preset value. When the

gun trigger is pulled note that the display changes to show WFS, Actual Arc Volt-age and Actual Arc Current. See Table B.4 for display summary.

PULSE PROCEDURES

In these procedures, the actual voltage greatly depends on the waveform used. The peak currents, background currents, rise times, fall times, and pulse times all affect the actual volt-age. The actual voltage for a given wire feed speed is not directly predictable unless the waveform is known. In this case, it is not practical to preset an actual voltage for the pro-cedure. Instead, an arc length adjustment is provided. The machine “knows” what the best arc length is at the given wire feed speed but allows the operator to change it.

The arc length can be adjusted between 0.5 and 1.5 on the wire feeder’s Voltage display. An arc length trim of

1.0means that no adjustments will be made to the pre- set arc lengths. An arc length trim greater than 1.0 increases the preset arc lengths. An arc length trim less than 1.0 decreases the pre-set arc lengths. The arc length adjustment is factored in at all wire feed

speed settings.

Increasing the arc length by 10 percent at a given wire feed speed also increases all the other arc length set- tings of the procedure by 10 percent. In the Pulse process, the display shows the Procedure Description, WFS and Arc Length Trim. Arc length trim is pro- grammed to a default at the factory and may be adjust- ed on the wire feeder. When the trigger is pulled, the WFS, Actual Arc Voltage and Actual Arc Current are dis-played.

WAVE CONTROL

The wave control settings of all procedures can be changed on the Power Wave 450 GMAW Pulse, GMAW and FCAW, Stick Process Selection Overlay. The wave control is a setup parameter that may be adjusted when the welding procedures are set. This feature pro-vides an easy way to change the arc behavior without creating a new procedure. The wave control setting of a procedure limits the speed at which the current waveform of that procedure can change. Typically, each procedure is programmed to have aver- age wave con-trol (at the center of the scale).

In Pulse processes:

The wave control adjustment allows the frequency set- ting to vary. Increasing the wave control allows the fre- quency setting to increase, and decreasing the wave control allows the frequency setting to decrease. Varying the wave control setting affects the droplet trans-fer and allows fine-tuning for different welding positions.

In GMAW and FCAW processes:

The wave control adjusts the inductance. (Inductance is inversely proportional to pinch.) Increasing the wave control setting decreases the inductance, which results in the arc getting colder and pinched tighter. Decreasing the wave control setting increases the induc-tance, which results in the arc getting wider.

POWER WAVE 450