AC DCEN/DCEP independent current control on PP256?

[acannell]

I just got my power pro 256 and its great.

I'm wondering if there is anyway to independently control the current levels for the DCEN and DCEP portions of the AC waveform while in AC mode, like millers advanced squarewave technology.

For instance, you could Tig weld aluminum in AC mode, and adjust it to 240 amps for the DCEN part of the waveform, and 110 amps for the DCEP part of the waveform, which would allow you to weld 1/4" aluminum with a 3/32" tungsten instead of a 3/16" tungsten. Much less heat, and much more precise arc because of the smaller electrode!

I'm pretty sure the PP256 does not have this feature.

BUT, is it modifiable somehow to have this feature? (I'm an EE)

Maybe you should sell an upgrade kit or something.

[performance]

ACannell,

No that is not a current or modifiable feature of the 256 or the 250EX. Only the Dynasty 350 and up have this feature, not the 200.

First,
You must understand what AC bias does, in practical terms while you are welding. In essence, it controls penetration and cleaning, same as the balance control of + vs. - stages of the AC cycle. This is in many respects doing the same thing as the balance control. It can offer a little additional "fine" tuning of the properties, but is definitely a redundant feature from a practical application standpoint.

Some of our new product legislated for next years production will have this feature...but it is a bonus feature, not anything that would prevent making a high quality weld or limit the adjustability of the welder in the slightest.

[acannell]

ACannell,

No that is not a current or modifiable feature of the 256 or the 250EX. Only the Dynasty 350 and up have this feature, not the 200.

First,
You must understand what AC bias does, in practical terms while you are welding. In essence, it controls penetration and cleaning, same as the balance control of + vs. - stages of the AC cycle. This is in many respects doing the same thing as the balance control. It can offer a little additional "fine" tuning of the properties, but is definitely a redundant feature from a practical application standpoint.

Some of our new product legislated for next years production will have this feature...but it is a bonus feature, not anything that would prevent making a high quality weld or limit the adjustability of the welder in the slightest.

Okie dokie. I got all this started in my head from the miller tig handbook. Maybe I mis-interpreted it, as follows:

On page 4 of chapter 6 of their TIG handbook, here: http://www.millerwelds.com/resources...Book_Chpt6.pdf

They have two tables showing machine and electrode setups for aluminum. The first table was just "AC", without even listing balance control. There, it says you need a whopping 5/32" to 3/16" electrode, at 250+ amps.

The table below it is for "advanced squarewave", and it says, for the same weld, you need only a 3/32" electrode. It shows AC balance settings, and also the independent current control setting.

So I think what you are saying is that the AC balance alone gets you almost all the way there, and I think I forgot that the first table doesnt even have AC balance.

So what electrode sizes do you recommend for 1/4" aluminum?

[performance]

3/32 should be about right.

Yes. That is what I am saying. Just as adding pulse to AC can do some of the same things as well as the AC bias...think about it...You are pulsing between two different current values, even though the heat may be concentrated differently. They do have distinct action on the arc, but they can be used to get similar results.

[Wrenchtamer]

I have been through the gamut trying to find the proper balance settings and electrode size for aluminum and to weld a corner joint in 1/4 inch aluminum I had to step way up to 5/32.

[acannell]

I have been through the gamut trying to find the proper balance settings and electrode size for aluminum and to weld a corner joint in 1/4 inch aluminum I had to step way up to 5/32.

Please describe your problems! Everyone here can learn from you!