Aluminium Problem

[Damaged]

Hi all,

Picked up the Kemppi today and have been having a play and have immediatley run into a problem:

I laid down a couple of acceptable welds on aluminium and thought wow what a machine but then the wire "bird nested" around the feed rollers, sorted that out then reset the feed tension so that i could stop the wire with very little pinch pressure, tried to weld but the wire was stalling as soon as it made contact with the work piece.

No problem I thought, have then been increasing the feed tension by a quarter of a turn and triying each time, to cut a long story short I can't get the tension so that it can stand the initial resistance of making contact with the work piece without slipping and not "bird nesting"

This is my first attemp at welding aly so what am i missing?

Many thanks,

Mick.

 

[malcolm]

The set up? Annoying stuff is aluminium. I managed to get my Clarke working with the soft grade of wire, but some prefer the stiffer stuff. To save you a bit of time keep an eye out for mentions of oversized tips on that page.

 

[shenion]

That is an issue with 4043 0.8mm wire. That is why most use spool guns.

Also use the next size larger contact tip as the wire expands considerably as it heats. 0.9mm tip on 0.8mm wire.

Alum wire is a pain, you need to tighten the rollers to get enough grip. That flattens the wire a bit as it is so soft and that causes drag in the liner.

I switched to 0.9mm 4043 wire and it was much easier to feed as it is stiffer. 5356 was much easier to use as it was harder and the feed was much slower.

 

[Damaged]

Thanks Malc,

The welder is set up with a teflon liner, I've done all I can with the tensioner, I'm running 100% Argon with 1.0 mm wire, only thing I can see is that I'm running a 1.0mm tip with 1.0mm wire.

Should I realy have to start drilling tips out or is there say a 1.2mm tip available?

Mick.

 

[malcolm]

That'll be it. I think it's because aluminium is so conductive to heat - heat comes back up the wire and makes it expand too much.

You can get much thicker wire than 1.2mm, so tips are available in that size. Though I recall I used a drill on mine to save on postage costs.

 

[matt1978]

Are you using Aluminium specific rollers?

They'll most probably have a 'A' stamped on somewhere, if you are using the rollers that came as standard, then I imagine they will be specific for hard wires.

Alu rollers are more of a U groove, where hard rollers are a V shape.

 

[Damaged]

Thanks Gent's,

Matt I asked for the welder to be set up for Aluminium but I cant see any marking on the rollers that don't relate to wire size.

Would the incorrect tip size on it's own be sufficent to cause the problems I'm having or do I need to change the rollers as well?

Thanks for your help,

Mick.

 

[matt1978]

I can only speak from experience, of Lorch and Fronius, but both companies use rollers specific to Aluminium and this is shown with a differing stamp........the Lorch ones say 1.2A for example.

4043 is one of the hardest Alu wires to feed, but 1.0mm is not that bad, certainly doesn't add up with the problems your experiencing.

Is it a 2 or 4 roll drive? Is the liner fitted correctly, (the teflon liner goes straight to the back of the rollers) so the normal steel cappilery tube is removed from inside the euro fitting?

 

[Damaged]

This Kemppi (miniarc mig adaptive 180) dosen't have an euro torch but the liner is within a couple of mill of the feed rollers, it's a two wheel feed.

I was hoping I'd bought a decent piece of kit and it was just me, hope that's still the case!

Appreciate the replys,

Mick.

 

[matt1978]

Try the 5356 wire, if you have problems with that, then it would point to a problem with the set up

 

[Damaged]

Will do,

Thanks Matt

 

[dannyweld]

at least use a 1.2 tip with alu, i use a 1.6 with 1.0 wire, why, because when the 1.0 wire passes through your roller its no longer round, but oval, measure the diameter of the wire and see what it is at its widest, thats what you need to clear. position the machine behind so the gun is straight on to the work. a small butane hand torch is handy to give the work a bit of a preheat. as soon as the rollers are tight enough to move the wire, thats about as hard as you can go, make sure the wire spool is tight, if it keeps moving after you stop welding it can wreak the wire, teflon liner for alu, if you got a kemppi gun it should do the job as there quit stiff, on my one i can rotate the nozzel which is good for alu welding.

 

[malcolm]

My understanding is that U shaped rollers do prevent aluminium wire from going out of shape, but it's more of a problem for production welders and has much to do with the life of teflon liners and little to do with actually laying a first bead with the devil's wire.

I tend to think DIY so wouldn't consider swapping rollers as the V shaped ones work fine and there are so many other ways for me to ruin my liner.

 

[Robotstar5]

For industrial use you can get a "motorized pistol", a small wire feed motor in the torch which pulls the wire to stop it kinking

 

[dannyweld]

For industrial use you can get a "motorized pistol", a small wire feed motor in the torch which pulls the wire to stop it kinking

push pull. the miller version is pnuematic (i think), costs over a grand here just for the torch, bulky also.
another tip, i always pull the alu wire at the tip with a plyers, just to get rid of any slack in the torch.

 

[Mikey D]

kemppi dont list any u shaped feed rolls , but they do some knurled feed rolls would theses be suitable for alu i wonder ? It doesnt say in the manual .
i think id drill out the tip just to eliminate that ....
cheers mike

 

[matt1978]

kemppi dont list any u shaped feed rolls , but they do some knurled feed rolls would theses be suitable for alu i wonder ? It doesnt say in the manual .
i think id drill out the tip just to eliminate that ....
cheers mike

No, Knurled rollers, will be even worse, they are for Flux cored wires.

Do they not list anything for Aluminium rollers??

Drilling tips out is not good either, because the Contact tip is the only way to pass the welding current to the wire, you need a good contact inside the tip.

 

[Mikey D]

thanks matt , now i know what the knurled ones are for ! no only two types of rolls listed standard and knurled (no u shaped or owt )
no tips bigger than 1mm either , although standard m6 tips fit ....

cheers mike

 

[dannyweld]

kemppi do alu tips example 1.0A, which has a 1.4mm hole, these tips are M8. you could change the contact tip holder. they also do a geat teflon liner. they also do a trapezoid roller with a bearing. if no bearing in yours a little bit of WD40, make sure the rollers can spin when you flick them with your finger, its easy to over tighten them. i just got a 1.2 roll of alu on monday, the tip has a 1.7 hole size.