Help with Miller XMT 350 MPa Aluminum Welding Setup

[Dan_Kingery]

Hello everyone,

I was hoping I could get some direction on our new welding setup we just purchased. We needed to get a setup for welding aluminum so we went with the Miller XMT MPa, S-74 MPa Plus wire feeder, and an XR-Aluma-Pro Plus gun. We're running it with 100% argon and ER5356 .035" wire. We got a Fume-Dog extractor for worker safety and I built a new welding table for it with our Millermatic 252. One of the other managers here was a welder before becoming an electrician and he tried setting up the new system, but it's sophistication surpasses his knowledge. We're having trouble getting proper penetration on the aluminum as we weld so it's basically just spraying onto the work pieces and only superficially joining them. Very similar to a CAD weld of copper to steel. I can break the welds with some effort.

Essentially what we're trying to do is weld 2" x 2" x 1/4" angle to the center of a 10" x 10" x 1/2 plate as a mast for conduit supports. We've tried a myriad of settings under both pulse mig and standard mig and can't seem to get it dialed in to penetrate that 1/2" plate for a good weld. We've preheated the pieces with a torch and tested the temp with a temp stick to make sure it was hot. I'm convinced the settings on the welder are what needs addressing. Has anyone got any experience with this setup and can give me some pointers?

[Munkul]

Does it show average amps during welding on that setup?
I had an older XMT setup with pulse pendant and it worked well but everything was governed off wire speed, it wasn't sophisticated enough to work its own wirespeed out.
If you're not getting the penetration you need more amps, and to get more amps you need more wirespeed.

[M J D]

What are your settings now? First off you would be better suited to 3/64" or 1/16" wire for that. With .035 I would think you would need around 600 ipm to get enough amperage.

[Munkul]

As a guide, you're going to want 250 amps for that particular weld. Maybe more.

MJD is right, you want 045 wire ideally, it will also be stiffer and less likely to cause problems with birdsnesting etc.

[ccawgc]

If you still can't get a good weld. Call Miller tech support and ask for a process engineer. They are paid to help you get Miller equipment up and welding and they know all the tricks.

[djd775]

Do you have experience with aluminum MIG welding? If not, you may need to change your expectations. Needs to be hot and fast. There are tons of settings on those units that I think may actually be detrimental in some cases. To start I’d recommend turning off all the pulse and synergic features and get to the point where you can set voltage and wire speed. For what you’re describing, I expect you’d want 3/64 wire, 25 volts minimum, and dial the wirespeed in on some scrap. Don’t take my settings as gospel, they’re just a guess.


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[djd775]

A couple thoughts to add:

I wonder if using 035 wire means you will have to max your wirespeed and dial in voltage from there?

Forgive my crappy attempt at welding 1-handed while holding the phone for video, but I very quickly made a couple videos in case it’s helpful. Edit…can’t upload videos here, see pictures below. I’m confident that this can be dialed in better, but I just guessed at a couple settings and ran with it. Also: make sure your stick out is enough, be prepared to travel faster than you’re used to with steel.


Note: no preheat, no prep, and I’m sure this can be dialed in better. Just a suggestion in case it’s a helpful starting point.

Material is 2x2x1/4 angle and 1/2x3 flat bar.

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[Country Metals]

I have an Invision MPa plus 352 and 2x miller 350p aluminum with push/pullguns.

I think the one issue with my Invision, which is kind of an upgraded XMT. Is it doesnt have the upper wire speed needed. I know I need 750+/- to weld 1/2" alum with 035 wire on the 350p.

I believe you need something like 29 volts with 750 ipm wire speed.

Also, make sure you set your gun on the XMT. You also have to set your gun SUP number into the feeder or the 2 different drive rollers wont be in sinc.

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