How to Use Double Pulse on Longevity's MIGWeld 250 MP
Kevin is adjusting the settings on the Longevity MIGWeld MP 250 - "MP" stands for "multiple pulse." He wants to use the welder's double pulse feature, and is trying to set all the parameters set before he begins welding.
He cycles through the various options - preflow, pulse amps, arc force, pulse time, pulse frequency. He turns down the welding current, then adjusts the volts, leaves the burnback and burnback voltage where they are, and the post flow.
The pulse amps setting is for when the machine goes from your welding voltage to your pulse voltage, or pulse amps, at the bottom of the pulse. The arc force is for setting the inductance - how well the arc pentrates. The pulse time is how long the pulse is between the peaks. Pulse frequency determines how often the welding arc pulses during the pulse time. The welding current is what you're actually doing the welding with. The end amps is helpful in 4T.
With 2T, you pull the trigger it welds. When you let go, it stops. With 4T, you pull the trigger, it starts welding and you can let go of the trigger while it continues to weld. When you pull the trigger again, it stops. When you pull the trigger the second time and hold it, the amps drop down to your end amp setting to cool itself off. The burnback time is for when you let go of the trigger and the arc stops, the welder gives it just a tiny more voltage to burn that wire back up to toward the gun so you don't have too much stickout when you finish. Burnback voltage is how much power you give it to control the burnback.
As for single pulse vs. double pulse, on this machine, with single pulse, you can adjust amperage and time. With double pulse, you can adjust pulse time, pulse frequency, pulse amps, arc force, etc. - you have a lot more parameters to adjust. Single pulse is the quick and easy mode, while double pulse is more complicated, but gives you a lot more variables.
Pulse in general allows people to weld thinner metal with good penetration and with less warpage and burn through.
Next Kevin welds some beads with double pulse on, then some without pulse. You can hear the harsher, bacon sizzling sound much more with the second set of welds.
Afterward, Kevin shows the welds. The pulse welds are a little tall, with the bead standing up a bit. Kevin says it may have been a little cold. So he could add some more voltage, more amps, or cut back on the amount of pulse time - make the bottom of the pulse smaller with more welding time at the top. He did get enough penetration and enough weld that he can just grind it down smooth it off - this is a cosmetic weld, not a structural one. The section without pulse was a little tall, too, then flattened out.
Kevin says he needs more time learning how to control the pulse. You can do a lot of different things with this welder, but you have to wrap your mind around it.
Speaking of wrapping your mind around it, Kevin has to do that with simpler things, too, as you see at the very end of the video ....
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