Taking a different approach to independent EN and EP amperag - Page 2

zank · Sun Feb 04, 2018 9:49 pm

When the waveshape comes up after pressing the gas/dig button, press the amps button to toggle between EN and EP waveshape.

Turbo · Tue Feb 06, 2018 7:38 am

That worked. Thanks

Dcohee1 · Tue Sep 29, 2020 1:33 pm

Does anyone know if the basic Dynasty 280 models are capable of the independent AC card upgrade as well? Or if u get any of the other wave shapes with it? Doubt it. Just bought that machine and wanna know as much as possible before I drop $500. Kinda why I got that machine, plus the deal I got on ebay. Lol Thankyou!

Oscar · Tue Sep 29, 2020 6:33 pm

Dcohee1 wrote:Does anyone know if the basic Dynasty 280 models are capable of the independent AC card upgrade as well? Or if u get any of the other wave shapes with it? Doubt it. Just bought that machine and wanna know as much as possible before I drop $500. Kinda why I got that machine, plus the deal I got on ebay. Lol Thankyou!

I believe it is only the dx model, but Miller would be able to confirm.

LtBadd · Tue Sep 29, 2020 6:52 pm

Dcohee1 wrote:Does anyone know if the basic Dynasty 280 models are capable of the independent AC card upgrade as well? Or if u get any of the other wave shapes with it? Doubt it. Just bought that machine and wanna know as much as possible before I drop $500. Kinda why I got that machine, plus the deal I got on ebay. Lol Thankyou!

As far as I know the upgrade is for the DX model, and the quote I got for the upgrade was $642, way over priced IMO
Call Miller and know for sure 920-734-9821

sbaker56 · Wed Sep 30, 2020 7:32 pm

This makes me really want to experiment with the Dynasty 280DX at school, I don't think it has the upgrade, but It still has an overwhelming amount of options to explore and when I used it the first time I kept it pretty basic for the most part. Those welds look amazing

LtBadd · Wed Sep 30, 2020 7:57 pm

sbaker56 wrote:This makes me really want to experiment with the Dynasty 280DX at school, I don't think it has the upgrade, but It still has an overwhelming amount of options to explore and when I used it the first time I kept it pretty basic for the most part. Those welds look amazing

I have a 700dx at work and having the independent adjustment is really nice, for general work it doesn't play a big role but there are times when it great to have.

ODNT · Fri Oct 02, 2020 1:59 pm

Zank - "and went as high as a 1.0/1.5 EN/EP ratio"...Care to offer any insight as to general effects of further imbalance or frequency variations? - I'm that dangerous noob w/dyn400 - Thanks!

LtBadd · Fri Oct 02, 2020 6:45 pm

ODNT wrote:Zank - "and went as high as a 1.0/1.5 EN/EP ratio"...Care to offer any insight as to general effects of further imbalance or frequency variations? - I'm that dangerous noob w/dyn400 - Thanks!

If you're welding thinner aluminum , say 1/8" or less then your EN requirements are not as great as 1/4" (obviously) so on the 1/8 you can use more EP giving you a lot of cleaning action. Best way is get some practice material and try different settings.
While Zank found for HIS application a ratio of 1.0/1.5 EN to EP that isn't a law written in stone, just his preferred settting for his application, IOW try it yourself...

On the 1/4" your pushing towards the higher end of amperage requirements, so you'll need higher EN, so the headroom for more EP may not be available.

Also remember you may want to use larger dia. tungsten to tolerate all this.

Oscar · Fri Oct 02, 2020 7:05 pm

Also the EN/EP ratios are always in conjunction with the AC balance. One is in the current domain and the other is in the time domain. If you watch Jody's video he explains where & how the balance comes into play.

ODNT · Sat Oct 03, 2020 3:16 am

Ok...I'll give it a shot at lower amps, but I'm almost always above 250A on aluminum and generally run lower hz as I don't see (maybe missing?) advantages at the higher amps. Thanks guys!

Poland308 · Sat Oct 03, 2020 8:56 am

It’s the switching of electron flow from en to ep that breaks up the oxidized layer. When electrons flow one way the heat is directed into the metal, but is resisted by the oxidation. When it switches direction it directs the heat more into the tungsten but also the change in direction of flow breaks up the oxidation layer. The faster you switch between the two becomes a balancing act, between cleaning and penetration.

Oscar · Sat Oct 03, 2020 6:14 pm

Poland308 wrote:It’s the switching of electron flow from en to ep that breaks up the oxidized layer. When electrons flow one way the heat is directed into the metal, but is resisted by the oxidation. When it switches direction it directs the heat more into the tungsten but also the change in direction of flow breaks up the oxidation layer. The faster you switch between the two becomes a balancing act, between cleaning and penetration.

It's actually quite interesting that during the DCEN portion the electrons do indeed traverse the entire aluminum oxide layer -- this is evidenced by the pure aluminum substrate indeed melting underneath, while the oxide layer stays in place, still in it's intact "skin" layer on the top. It's only when the base metal becomes the emitter on the DCEP cycle that the oxide layer is actually broken up, and floats out of the way. I found out the reason is because it is believed when the base metal becomes the emitter, there is an electric field that is created that is not created the same way during the DCEN cycle. On the DCEP cycle, the electric field causes the oxide layer (which is normally a dielectric) to suffer dielectric-breakdown and then is "forced" to become a conductor, which causes physical breakdown of it's own grain-boundaries, and then floats out of the way as the aluminum underneath becomes molten.

Source: Cathodic Cleaning of Oxides from Aluminum Surface by Variable-Polarity Arc, SUPPLEMENT TO THE WELDING JOURNAL, JANUARY 2010, R. SARRAFI AND R. KOVACEVIC

invader28 · Sat Oct 03, 2020 11:14 pm

Great find and explanation!!