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Up Topic Welding Industry / General Welding Discussion / AC GMAW?????
- - By PlasmaHead2 (***) Date 05-12-2015 23:31
So whats all this Im seeing in the lincoln 2015 catalog about AC GMAW???
Anyone tried it yet? Total marketing Lies about something they are working on but isnt out yet?
http://www.lincolnelectric.com/assets/US/EN/literature/te12009.pdf
link to Linc's PDF on the over view;
http://www.lincolnelectric.com/assets/US/EN/literature/te12010.pdf
And that ones the weld process guide...
So SOMEONE'S played with it...

Heading to google to find out how much a powerwave300/500 is.....:eek: :cry:
-Clif
Parent - - By aevald (*****) Date 05-13-2015 00:22
Hello PlasmaHead2, I don't know about Lincoln's offerings, but OTC Daihen has had AC GMAW for a while now. Unfortunately I missed the demo's that were held on it to the North of where I reside. From what I have seen in the literature it's pretty impressive stuff and directed strictly at Aluminum work. I'll see about attaching what I have from them about this. Best regards, Allan
Parent - - By PlasmaHead2 (***) Date 05-18-2015 22:02
The boss only knows 2 colors.... Blue and Blue.
He even has a small collection of the bobble heads they make sitting above his desk...
If its not Miller he has no idea what it is or does...
Parent - By aevald (*****) Date 05-18-2015 22:17
Well if he likes blue he should be checking out the Invision offerings from Miller. We have one of these units and it's pretty impressive from the experience that I have had with it. There are also shops in our area that utilize these machines, most of them are employing them to perform welding on light gage stainless steel and aluminum applications. They are however not AC GMAW. Best regards, Allan
Parent - - By ssbn727 (*****) Date 05-13-2015 06:51
Kind of reminds me of the sort of set ups NASA used to use when building their main fuel tanks for the shuttle launches except that for the most part, they used PAW instead of GMAW and called it: "Variable Polarity Plasma Arc Welding" or VPPAW... And the equipment used was huge and cumbersome compared to what both Lincoln and OTC Daihen have designed for this process which is IMHO, could also be called: VPGMAW, or Variable Polarity Gas Metal Arc Welding... But since these machines are designed primarily for Aluminium, then I guess AC GMAW is satisfactory for now...:roll: I only hope that there's no sacrifice in quality with AC GMAW compared to VPPAW just so one could increase deposition rates and arc on time...
We'll soon find out.:eek::roll::smile::grin::lol::wink::cool:

Respectfully,
Henry
Parent - - By js55 (*****) Date 05-13-2015 13:06
My first instinct would be that this is a marketing gimmick. I have no doubt that there would be some benefit to AC. However, somehow I suspect the price tag will render it too expensive to justify. Though this won't prevent marketing from trying. We welded boxcars full of aluminum assemblies with DC GMAW for years and no problems. I would be curious as to the problem that is theoretically being resolved.
We have seen the same evolution with AC SAW. Perhaps in very specialized applications there is something to it. But Marketing NEVER limits itself to specialized applications.
Parent - By aevald (*****) Date 05-13-2015 13:20
Hello js55, when AWS held their convention in LA a number of years ago and before they combined to form Fabtech, I was fortunate to attend. Panasonic had a GTAW power source that utilized a DC wave component imposed over the AC current on one of their GTAW welding power sources. I got a chance to "hot rod" it. You could use 3/32" tungsten and make welds almost "instantly" without destroying the tungsten. Outside of seeing and using it at the convention I did not hear much about it anymore and I was also told that Panasonic sold off their production/rights to techology to someone else, but I can't remember who that was. Best regards, Allan
Parent - - By Lawrence (*****) Date 05-13-2015 13:50
Those are good points JS55.

Not everybody needs the whistles and bells.

But for automated GMAW on materials <10ga   AC GMAW can really do some good things with both travel speed, quality and mechanicals.  The ROI is easy to find.

As far as AC SAW goes ?    Try making a square-groove CJP on 1/2' steel with a 5/32 electrode from one side with a DC SAW.     AC SAW can do this from 1/8" up to 1/2" with 99%+  First pass UT yields.     Not everybody needs that.. But those who do are saving uncounted hours in, beveling, back gouging, material flipping and all the other issues that go along with CJP SAW joints.
Parent - - By js55 (*****) Date 05-13-2015 16:15
Lawrence,
No doubt.
But I bet we see them in fab shops from coast to coast with supervisors scratching their heads as to why they have one. Or ten.
And of course perched up on the stand at the back of the power source are two bottles of quad mix gas and a 600 lb drum of that special high priced AC carbon steel wire. :smile:
Parent - By aevald (*****) Date 05-13-2015 16:57
You make a very good point about "technology", everyone in a shop needs to buy into the use and purpose for new technologies or else they are only that, NEW and unused.

See that fairly often with aluminum welding systems in many of our local shops. Some have the Lincoln systems and others are using the Miller ones. When they take the time to work with them and get it right the results are pretty impressive, otherwise, standard CV is selected and the results are what they are, status quo. Best regards, Allan
Parent - - By 803056 (*****) Date 05-13-2015 18:10
JS55, we're on the same page with this.

A number of years back, a contractor was fabricating aluminum with GMAW-P. They were experiencing a number of issues, one being incomplete fusion. I asked the supervisor why they were using pulsing on 1/2 aluminum. I mentioned that one of the problems with aluminum is the high thermal conductivity and the need for as much heat as one could muster. I ventured to say that there was no need for pulsing on aluminum and that they would be better off with straight spray mode transfer.

His response was, "Considering what we paid for those pulsing units, if I didn't use pulsing, I would be out of here so fast, I wouldn't have a chance to put on my jacket."

Bells and whistles, how often do we see the "options" actually being used?

Best regards - Al
Parent - - By Lawrence (*****) Date 05-13-2015 18:31
GMAW of Aluminum  1/2" thick base metal .... Fillet weld

Spray Transfer will make a 5/16" fillet... Gonna be VERY difficult for the average welder to make a smaller single pass fillet

GMAWP will easily make a 1/4" fillet with the SAME AMPERAGE as the traditional spray transfer weld. 

The 1/4" fillet is a 57% reduction in volume and ARC-ON Time !

Put that in your pipe and smoke it !

The old CC  GMAWP power supplies are melted down for scrap...  Any GMAWP aluminum machine produced in the last 10 years can be set to weld on thick aluminum without lack of fusion issues.

Now if production is essentially thick Aluminum and not very much of it... Sure, save some cash.

But you can get a 350 amp GMAWP power supply for about $500 more than a Transformer unit....  If I have a business that might see expanded production or Aluminum thinner than 3/16"..... GMAWP is the way to go.
Parent - - By 803056 (*****) Date 05-13-2015 19:15
Who said anything about fillet welds?

And, yes, these were old ones, but not so old they were limited to 60 or 120 pps. There were Millers, nice machines, but no one knew how to set them up and for what they were attempting to do, spray would have been the way to go.

Pulsing on thin aluminum, I can buy that, but many of the problems I encounter with aluminum and incomplete fusion is because the contractor is attempting to use short circuiting transfer for out of position work.

Al
Parent - - By Lawrence (*****) Date 05-13-2015 20:56
I don't get the short circuit thing anyhow..

Aluminum with GMAW spray in all positions with ease... Whether it's pulsed or not pulsed... Thick or thin... Day or night, preheated or not...  Soup or Salad
Parent - By 803056 (*****) Date 05-13-2015 21:11
It is called education and experience. It was lacking.

Al
Parent - By welderbrent (*****) Date 05-13-2015 22:48
Between gas shielding composition, welding parameters, and other factors involved (and this is a question as I am not that versed in Aluminum period and especially outside GTAW) I didn't know you could truly 'short arc' aluminum? 

And as has been said many times on this forum, why would you want to and how many applications would there be for it? 

I tend to agree with others even though my observations are based primarily upon carbon steel applications, there are a good many latest, greatest, fancy, over the top gadget packed machines available anymore that you need an electrical engineers degree and 6 months worth of training to operate.  Companies buy them expecting this vast improvement in production and quality and then the guys won't use them, at least with all the gadgets working correctly, because they don't like change, don't like giving up personal control, don't like everyone else knowing what they are actually doing to get the job done (job security) and much more, so the machine sits in a corner or on top of a shelf (out of sight- out of mind) and goes to waste. 

The key is generally training and time.  Don't expect immediate results.  Encourage the time it takes to get it right and figure out how to use it.  Even send someone to special training at a school or at least the manufacturer (I wish someone would do that for me and computers, oh, wait a minute, I am that someone.  I need to send myself for training). 

He Is In Control, Have a Great Day,  Brent
Parent - - By Jarhead1 (**) Date 05-13-2015 20:07
GMAW Aluminum 3/8" and above I found needs to be preheated to achieve good penetration with a basic GMAW power source.
A good pulse machine were welding 1/2" Alum all day eliminating preheat.

Although, need to check this out AC GMAW....OTC and Miller has demos....
Parent - By ssbn727 (*****) Date 05-18-2015 08:05 Edited 05-18-2015 08:17
Oh No!:eek: Here comes the preheat Aluminium debate again...:roll: You don't preheat heat treatable Aluminium.:grin::cool:

Respectfully,
Henry
Parent - - By js55 (*****) Date 05-13-2015 19:53
Al,
I know exactly what he was experiencing. Long ago in a galaxy far far away working for a fabricator with multiple shops one of the shops bought some very expensive machines that they didn't need. Come hell or high water they were using those machines. And again, with the company I now work for we have some very VERY expensive machines that are used occasionally. One of the first things I was tasked with when coming here was finding a way to make them work in more situations. Being familiar with the technology I told them it was a waste of time. To this day they collect more dust than anything.
Parent - By aevald (*****) Date 05-13-2015 19:57
If you'd like, you could send them my way js. I'm pretty sure that we've got some room for them somewhere on our shop floor! Regards, Allan
Parent - - By PlasmaHead2 (***) Date 05-18-2015 22:00
Can you find out how much for one of them? Dust included??:wink::twisted:
Parent - By js55 (*****) Date 05-20-2015 20:06
I am not connected with them anymore.
Parent - By kcd616 (***) Date 05-19-2015 01:26
Clif,
I am interested in the Lincoln powerwave
if 1 of my machines dies
I will give it a good look
but the little woman and granddaughters have other plans for the $$$$$:eek::roll::sad::wink:
I have heard good things from my friends at lincoln about it
sincerely,
Kent
Up Topic Welding Industry / General Welding Discussion / AC GMAW?????

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