I've been defeated. 1mm Ali bird droppings inside.

[Brad93]

bumped into a guy on BOC yesterday struggling to weld 1.00mm aluminium parts on a jasic machine.
Said if he couldn't get on I'd give it a shot.
He came round today and try as I might I could not get these looking nice. Even tried pulse on AC but I'm lost. Taking parts back to him now. I'm going back to school.

 

[Richard.]

Challenging job. Heat is your enemy here. If you can hang on to a set and send em to me I could have a go and pass you some ideas (if successful of course)

 

[Brad93]

Literally just require a neat tack two on bottom two on top.
Price is £3 per part so worth the money.
He supplied a steel jig.
My settings were 10% EP, 200Hz AC Frequency. 1.6mm HFT Multistrike tungsten. Couldn't stop tungsten from balling really.

 

[Richard.]

Let it ball mate. 10% ep is a big part of your problem.

 

[Brad93]

I can't go any lower that that

 

[Richard.]

That's too little cleaning mate is what I meant.
You need to make sure you have enough cleaning to remove the oxide layer or your arc won't be stable with contamination in the pool. I'd say try 20 maybe even 25%. If your tungsten ball is stopping you keeping a focused arc step up to a 2.4 and grind a sharp point.

 

[hotrodder]

I'd turn the AC frequency down a chunk too... yeah the arc is more focused and stiffer but it's also harsher and more prone to dancing about when striking up usually. While more EP will round the tip off more it'll also soften the arc and make it less prone to dancing between each side of the joint while placing the intial tacks IME i.e. i'd rather use a blunt 1.6 for tacking even if i switch to a sharper 2.4 for welding because i'm running too many amps for a 1.6 to survive any length of time

The top looks easy enough to me as it's a thicker lump so can strike up on that, wash the pool over and add a dab of wire.

The bottom... if someone asked me to make a batch of them i'd ask if the design can be changed slightly. If the tab could be a little larger it'd be sooooooo much easier to weld. Ideally i'd want the centre hole to be a nats larger so the 'split tube' would fit inside. If that can't happen 'cause the tab will end up too big then i'd strike up where the green circle is



and instead of a single dab tack move and add a couple more so it can be tickled with a belt sander if necessary without removing most of the weld. The red arrow suggest arc length is a bit excessive to me

 

[Brad93]

Everything your saying sounds all too familiar haha.
Yes arc was jumping between sides couldn't draw a pool into the corner of joint at all.
It's a tube for a thermometer in oil.

Where the red arrow I just kept trying and failing and that's when I gave up.

 

[Brad93]

I did ask for some spare material to get settings dialed but it's a rush job he needs to courier out tomorrow and it was all laser cut. I think I will buy some 1mm material of my own and practice some of these.

 

[Richard.]

I don't think the thickness is creating your issues, 1mm Alu is very easy to weld in more sizeable parts. It's the size of the bottom plate.
As said above if it was a fraction bigger it would be waaaaaaaay easier to get a decent stitch on it without heat fighting against you
I too would happily tack that with a 1.6 and a balled tip wouldn't cause too much of a problem. Far less than a sharp tungsten with next to zero cleaning action going on. Personally to weld those your not going to need that much current and I can't imagine a 1.6 getting too balled up before it stabilises even with 25-30% ep and I'd probably just stick with it for the duration.
I don't think personally 200hz is too far off the figure where I'd be. 150-200 somewhere in that region would work for me as I'd strive to keep that arc as tight and focused as possible.

 

[Shox Dr]

Not that its going to happen this time, but if there is a 'next time' Id ask for the base to be wider, once welded the excess could trimmed off

 

[Brad93]

Probably just get farmed out to the guy who done them before in Chelmsford, it was only that it was a rush job that he brought them round on a Sunday

 

[Richard.]

Probably just get farmed out to the guy who done them before in Chelmsford, it was only that it was a rush job that he brought them round on a Sunday

WHHHOOOOA. Just hold on a min.
Don't let someone else do them. That's admitting defeat. Your more than capable of doing it.
I'd never pass on a welding job on to someone else because it was hard. I'd make dam sure they went out.

 

[hotrodder]

Personally i'd rather redesign the part than practice/dial in the settings to do them consistantly and quickly. It's an odd, fiddly and difficult way to make a thermometer mount IMO... whether it's laser cut from flat sheet and the split tube is formed or it's laser cut from a mix of tube and sheet there's simpler and more elegant ways to make those

 

[Brad93]

WHHHOOOOA. Just hold on a min.
Don't let someone else do them. That's admitting defeat. Your more than capable of doing it.
I'd never pass on a welding job on to someone else because it was hard. I'd make dam sure they went out.

I wouldn't usually mate but the guy has left it late, and needs them out the door tomorrow. Personally if I had this job come in and I had plenty of time, I would have bought a sheet of 1mm 1050 and practiced until I was content I could make a nice job of it.
I've also got two days of training and tests wednesday for MMA so could do without the stress.

I will say this, it seemed that I was just blowing holes the moment I arced up so I just went down the workshop and ended up spending the best part of an hour playing around with the other settings on the Lorch, and discovered a few things.
It has start current, which I already had set to 15% (I am using a pedal though) but I had not altered the start current time, upon changing this, bang first improvement arc started a bit softer.
Like suggested I turned the Frequency down to 150 which has softened the arc immensely, also balance up to 25% EP much better arc starting and stabilisation. I then found this little pair of settings on the additional parameters list, adjusts the positive amperage on start up and during welding.
I can lay a bead on the cut edge of a roughly 3cmx7cm piece of 1.5mm 1050 whilst now keeping a pointed 1.6mm tungsten.

 

[Brad93]

It was the two settings at the top I played with. Can't remember which way round it was but i changed one to 50% and one to 10% think it was the setting 1PE i changed to 50%. The tungsten then stayed pointed and only the very tip balled. Before hand my tungsten was balling completely even on 10-15% EP, the minute I lit the arc.

 

[Brad93]

This setting has also drawn my attention, not sure if I am reading it right? Does this mean the minimum current I can get on the machine when using the pedal is 10amps? How does it know the size of the electrode I am using? @matt1978

 

[Brad93]

What I will do tomorrow is ask the guy if he can do me a favour and let me keep a few, and I'll post them out to anyone who fancies having a go. If not, I will mock some up once ive got the 1mm sheet.