B-16

STT WAVE SHAPING PRINCIPLES

Appendix B

 

 

 

2.Pick a wire feed speed from the Wire Feed Speed pulldown menu. We wanted to start with a 130 in/min. WFS. But 130 is not a workpoint in the selected wave shape application. Use the Workpoint Editor window to change the second workpoint (170 in/min.) to 130.

3.Select 130 from the Wire Feed Speed pulldown menu. Also, be sure to set the PowerFeed’s wire feed speed to the same WFS as the selected workpoint and set the trim to 1.00. (In this exercise, the WFS is 130 in/min.) Set the PowerWave mode and Arc Control settings to ‘OFF’.

WorkPoint Editor

WorkPoint Editor

0

90

 

 

 

 

 

 

 

 

 

 

 

 

1

130

 

 

 

 

 

 

2

200

 

 

 

 

 

 

 

 

3

225

 

 

 

 

 

 

 

 

inch / min meter / min

Go Figure

 

28750067

 

STT Waveform Editor

Wire Feed Speed

200

Edit

 

90

 

 

130

 

Peak Amps

200

 

350

 

 

225

 

 

 

27850068

4.If you are using the expanded STT Editor window, check the box next to the pinch/peak variable. This will fix the ratio of pinch start to peak amps. Selecting the Simplify Editor option (see the tools menu) automatically fixes this ratio.

NOTE: The STT process reacts to changes in the arc. When a short occurs, the STT routine responds to the short in a controlled fashion. The STT process does not use an adaptive loop. The process adapts to changes in stickout only by changes in the number of times shorts occur.

5.While welding, adjust the STT variables to improve welding performance. Maintain a constant 5/8 in. stickout (torch tip to work distance.)

Our Experiment: The weld produced by this setting is too hot. We burned through the 16 gauge fillet. The arc is too long and is producing too much spatter.

First, we reduced the peak current to 250 amps. Welding again shows that the arc length is now correct, but there is still too much heat in the arc.

Second, we reduced tailout from .100 to .140 (increasing tailout reduces the heat input). We welded again and found there was still too much heat in the arc.

Next, we reduced the background to 35 amps. This resulted in very good fillet welds on 16 gauge steel.

The starting screen can be adjusted at this time if needed. The STT waveform incorporates a soft start feature. The initial pulse to start the arc can be adjusted as necessary to achieve excellent results on a wide variation of applications.

Our goal was to optimize the welding at only one workpoint. The 130 in/min. workpoint is fully developed. If desired, you can save the new application, select the next workpoint and optimize the welding at that wire feed speed in a similar fashion as the first. The Go Figure function can assist in interpolating/extrapolating the variables at the next workpoint.

WAVE DESIGNER

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Image 70
Lincoln Electric IM649 manual STT Waveform Editor