Hi-Freq intensity

Date 08-26-2007 19:07 Edited 08-26-2007 19:46

Hello makeithot, one of the places that you may see a difference while adjusting the hi-frequency dial is in the area of cleaning around an aluminum or magnesium bead. If you weld a bead on aluminum that had been cleaned properly you will notice the nice shiney bead and then on each side of the bead there will be a whitish zone, you can reduce the width of these zones by decreasing the intensity of the hi-frequency. You can also affect the cleaning action in the arc by increasing or decreasing this setting. Having said that there is also a direct correlation to this when considering wave balance if you have a newer machine. The newer power sources may be equipped with many different wave balance functions that will affect the cleaning action of the arc. Variable hz controls can have some effect on cleaning, pulsing can sometimes have an effect due to the increase and decrease of arc energy associated with it, pps can show some effect there are a great number of new technological advances in arc control with the GTAW process. The greatest effects of the hi-frequency will likely be noticed on an older machine without wave balance adjustments or as I believe is the case that you are describing when you are using the add-on box to utilize a tig torch off of a seperate AC welder, either a gas-drive or an AC cracker box or similar power source. As far as the effects of this function when welding with the DC start only position, I have only noticed an affect as to the distance that the arc will initiate from the end of the tungsten to the work. I would also like to include that Lawrence and Tommyjoking can likely address this topic very well and give additional light. A few thoughts for consideration, Best regards, Allan

By Lawrence (*****)

Date 08-26-2007 20:31 Edited 08-26-2007 20:35

I'm going to disagree with Alan on this one... Call it a teachable moment.

The HF (high frequency) comming from a GTAW power supply has only one purpose... Establishing an arc.. It jumps from the tip of the electrode to the work and the welding current follows.

In no way does the High freq add to the cleaning action other than by eliminating of rectification.

The cleaning action comes from the DCEP or (Reverse Polarity) side of the AC half Cycle... As the current goes in one direction, Ions go another direction. On the half cycle when the Ions go to the work, they blast off surface oxides and cause what we call cleaning action.

You can test this by holding (with insulated pliers) a piece of aluminum that is not connected to the work clamp near the end of a tungsten electrode push down on the foot pedal, and watch the blue high frequency current jump from the electrode to the aluminum, some folks call this foxfire... What you won't see is any etching action.

So to get to the questioner... Adjustment of the HF may be necessary if longer welding leads are used or if rectification is a problem... if the arc is striking ok than no HF adjustment is necessary.

By aevald

Date 08-26-2007 20:54

Hello Lawrence, as I've always said I come to the forum to learn or to be corrected and to hopefully pass on what I have perceived to be correct. My statements on this subject are somewhat from experiences that I have had and somewhat from statements or information that I have read or have been told from others. I thank you for the correction and I knew that if I miss stated something someone would correct me. Part of my reasoning for making this statement in the first place has to do with the fact that AC current in the GTAW process cannot take place without the high frequency to carry the current at the transition point from DCEP to DCEN. I was also told that the oxide break-up that occurs is aided by the hi-frequency intensity, apparently this was incorrect. Another one of my reasons for this statement has to do with the use of hi-frequency in the continuous position when welding with DCEN current, when I have done this i notice a different type of arc than when using the start position only for the hi-frequency, this was the additional reasoning for considering the effects of the hi-frequency. Once again Lawrence, thank you. Regards, Allan

By ssbn727 (*****)

Date 08-27-2007 00:34 Edited 08-27-2007 01:49

Excellent response as usual Larry!!! ;)

However I'm still curious as to why "Makeithot" does'nt see, and the key words here are: "don't see a noticeable difference in the arc" while playing around with the dial... Now I have'nt serviced any of the newer ac/dc squarewave inverters as of late but, I have serviced many a Synchrowave or 330ABP's, Miller Goldstar's and many other brand name transformer rectifier/Highfrequency AC/DC, CC power sources, and I know that if you "play around with the dial" where the high frequency adjustment is, you will most definitely see a noticable difference in the arc and I don't mean in the etching effect that Larry was describing... I'm talking about the effect of the continuous delivery of high frequency which aids in maintaining the arc in all of the sinosudial wave type power sources that I worked on... Please let me attempt to elaborate...

That "Dial" Makeithot is describing is basically a knob connected to a potentiometer that's mounted behind the sheetmetal plate where the dial is painted on... It's the potentiometer that controls the amount and intensity of high frequency current that is stored in the Hi -Freq capacitor that's also part of this circuit...

As one adjusts the placement of the knob at different locations situated on the dial, the intensity/amount of hi-freq will vary accordingly, and the effect will be noticeable but not in the same way Larry describes because, I also agree with Larry that the Hi Freq does'nt actually cause the "Etching"/cleaning effect on aluminum... It's the waveform's depth & time into the negative half cycle that causes the cleaning action... The high frequency only maintains the arc from extinguishing itself as it passes in to the negative half cycle whereby with out it, the arc would die out!!! Lawrence is also correct in describing the proper reason for the need to adjust the high frequency intensity, and this is why I'm curious as to why Makeithot does'nt see a noticeable difference in the arc!

So if one does'nt move the position of the power source, and it's within the recommended distance from the circuit breaker/wall panel box, should the high frquency adjustment from let's say - 15 to 70 have any noticeable effect in the arc characteristics??? You can almost bet that it will if the components that make up the high frequency circuit are "all" working properly!!!

In other words, if there is no noticeable change in any of the arc characteristics when adjusting the intensity of the hi-freq then there might be something wrong with the potentiometer or another component within the high Frequency circuit, even the old hi-freq contact electrodes could be worn out or need to be properly adjusted in the gap because, too much hi-freq intensity does cause a very volitile arc that exhibits much inconsistensy in the plasma stream almost like a pulsing effect on the puddle as the shielding gas inconsistently ionizes at a very intense rate.

The opposite occurs in the arc characteristics when there is not enough Hi-freq intensity: The arc tends to sputter at an erratic rate like it's having a hard time keeping the arc on, and depositing alot of "black soot" due to the inconsistent shielding gas arc plasma ionization if it occurs at all!!!

So in conclusion and based on what little Makeithot describes as to what is actually going on as far as the arc characteristics are concerned, if he's not noticing any difference in the arc when adjusting the hi-freq intensity then there's something happening within the High frequency circuit that's NOT working properly!!! I'm also presuming that he's not doing these adjustments while simultaneously welding, correct??? ;) Also, if it's a squarewave inverter type, then it could be something else all together because I'm not familiar with their internal circuitry ;) :) :)

Respectfully,
Henry

By makeithot (***)

Date 08-27-2007 01:02

Henry, you are correct in your assumption that I am not adjusting the control while welding and will try that to further see the effects of which you speak. This is not a real fancy piece of gear it is a Hi-freq box added on to my portable to inable me to weld aluminum. Made by miller. It does weld quit well from my point of veiw I am trying to fiqure out why you would change the hi-freq setting and what is the criteria for doing so? It is my undrstanding then at this point that the hi-freq is used in arc intiation for stainless so that you do not have to touch or scratch your tungsten. For aluminum it is used to stabalize the arc through out the AC cycle and has nothing to do with the cleaning action of the arc.

By ssbn727 (*****)

Date 08-27-2007 01:46 Edited 08-27-2007 08:57

That's correct Makeithot! The Hi-freq box that you have if I remember correctly should have a toggle switch that gives you the option of having the High frequency on "Start" only to initiate the arc as one would want when GTAW stainless, and the other option of switching the Hi-freq to "Continuous" so that the arc does'nt extinguish itself as each half cycle otherwise known as a "hertz" in electrical terms passes through the zero current point while going towards the negative half of each hertz or cycle which occurrs 60 times (here in the US & Canada and 50 times in Europe or Asia for the most part), every second the arc is on.

Can I ask what type of portable you're using and what brand?

If there's too much High Frequency intensity when one is using a three phase power source output, one will notice that the etching/cleaning action is inconsistent in so much that there's more etching in some areas and less in other areas along the length of the weld due to the fact the the high frequency itself is superimposing current in many more hertz or cycles per second on top of the output current from the power source itself. Therefore, destabilizing the negative half-cycle or hertz of the output current. When using a single phase power source, the effects will not be as drastic yet nonetheless, very noticeable when it comes to having too much or too little high frequency current being superimposed over the output current. This is what i mean by being superimposed:
http://www.millerwelds.com/education/basicelec/

Is this the type of High frequency box you're talking about?
http://www.millerwelds.com/pdf/spec_sheets/AY5-0.pdf
Or is it one of these:
http://www.millerwelds.com/om/o136255a.pdf
http://www.millerwelds.com/om/o096906b_mil.pdf
http://www.millerwelds.com/om/o610g_mil.pdf

Respectfully,
Henry

By makeithot (***)

Date 08-27-2007 17:02

Henry, I am curently running a Miller big40 deisel. The hi-freq is the one you have indicated - HF-251-2 with the foot peddle remote ,aux power to this unit is 240volts 20amps as supplied by the welder. Thank you all for your insights, information,experiences and questions I am learning lots

By aevald

Date 08-27-2007 01:51

Hello Henry and Lawrence, after reading your post Henry can I possibly say that in an indirect manner the hi-frequency does have an effect on the cleaning action that is provided by the arc? I ask this based on the fact that if the hi-frequency isn't adjusted or working properly the arc will be lacking stability and possibly exhibiting altered cleaning action. I know I'm being a die-hard here so please forgive me.
I have another question for the two of you. A while back and I can't actually remember why, I took the leads on a syncrowave 250 and switched them(moved the torch to ground post and moved the ground to the torch post), I then tried to weld in the AC mode as normal, it was a catastrophe. The arc was all over the place and I couldn't get a puddle to save my tail end. In my mind this shouldn't have had an effect on the welding as it was being done with AC current, yet I also surmised that the hi-frequency portion of the current was being fed through one of the posts in particular and that by my changing the configuration of these I had somehow upset the proper operation of things. Just wondering what the explanation for this would be? Thanks again gentlemen and trust me, I don't doubt your information I just like to have a clear understanding. Regards, Allan

By DaveBoyer (*****)

Date 08-27-2007 04:25

I have a lot to learn from this thread too, but with regard to Allen's reversing of the leads, the problem is that the HF is induced on the terminal that is supposed to be hooked to the torch, and by reversing, You hooked the HF to the work lead. The problem is that the HF is able to bleed off to ground due to the size of the work, and its conection with watever it is resting on. HF doesn't need a good low resistance path to bleed off. I don't think the Miller Dialarc 250 HF had an ajustable HF, so I guess it was always full power. My understanding of at least one reason to be able to reduce HF intensity is to keep interference to a minimum. I have not seen any machines hooked up with the proper grounded steel [not flexable] conduit that is required by the FCC for type compliance as stated in the owner's manuals, and I do know that when the Dialarc was hooked up at My buddies garden center the HF would interfere with the electronic adding machine. In reality the HF and the feed cables are a radio transmitter, and that is why it falls under FCC regulation. As to Henry's mention of a 3 phase AC transformer TIG welder, I am curious to know which machines are configured this way, I didn't know there was such a thing.

By Tommyjoking (****)

Date 08-27-2007 05:36

makeithot

Nothing to add really to the good posts above...

Reason to change the setting: If you arc wanders, flutters, flashs and (all connections are good especially ground, tungsten in proper shape, gas, elec supply etc. parameters are proper) then increasing intensity can bring back a more desirable stable arc and increase its ability to start easily (machine without arc start boost). Why not just keep it at max all the time?? Well you are more prone to get inadvertantly bit (shocked) and increase chances for arc strikes on the ground side (think part laying on table). I always run it as low as it will run well....put a lead twice as long on the machine or a heavier lead and you might have to crank it up a bit to get the same results.

Hope that helps
Tommy

By aevald

Date 08-27-2007 05:37

Hello Dave, your explanation of the problem with reversing leads makes total sense and I thank you for that. I somewhat guessed that the hi-frequency was induced on the torch side, but it didn't really click as to the problems with reversing this orientation until you gave your explanation. Many thanks again. Best regards, Allan

By ssbn727 (*****)

Date 08-27-2007 05:57

Hi Dave!
Some machines come out of the factory with what is called a jumper link buss that is the location where the primary input cable is connected to, and basically it let's one run their power sources with either single or three phase primary input power, and at different voltages depending on the configuration one sets for the jumper links themselves and depending on which model number one orders.

All of the "Big Three" and other major welding power source/equipment manufacturers offer this similar feature on most of their power sources, and some of the models can actually adjust to the proper primary input voltages regardless of what someone might've thought was the voltage!

Btw dave, I was referring to many models of AC/DC Transformer rectifier type power sources that were either designed for single or three phase or in some instances, both single or three phase primary input and with a choice of voltages. ;)

By DaveBoyer (*****)

Date 08-28-2007 04:20

Henery: I think it would take more than just a transformer to have 3 phase primary [I mean actually USE all 3 phases] and an AC output. I know it can be done with an invertor, and there may be other technologys for square wave where power is stored and discharged that would work with 3 phase primary. With simple transformers like the Miller AB/P, or the Lincoln 300-300 the primary is single phase because there isn't an easy old tec way to do it otherwise.

By ssbn727 (*****)

Date 08-28-2007 09:20 Edited 08-28-2007 09:33

Hi Dave!

I respectfully disagree with your assumption that one cannot make a 3 phase version of a CC, AC/DC, transformer/rectifier power source because in the early eighties, I serviced many of them made by Miller/Airco, Lincoln, Linde/L-tech/Union Carbide, Westinghouse, Thermal Dynamics and other brands that I do'nt remember off the top of my head.

The only requirement was to purchase the equipment via factory notification... In other words, order the equipment through the distributor and the factory would have certain amount of time to assemble the order and ship it to the distributor direct or to the customer's location for distributor installation and of course payment had to be made prior to delivery... Now granted, some manufacturers did'nt offer certain models with the 3 phase option because they were primarily designed for the single phase market but, the majority of the many models offered by the major welding equipment manufacturers could be ordered in either single or 3 phase primary input

This was done quite often for industrial accounts that needed the equipment and were using only 3 phase primary such as the utilities like Con Edison, Automobile plants like General Motors, the Brooklyn Navy yard, Grumman aircraft, Fairchild Republic, Many of the Major Airlines maintenance facilities, municipal maintenance facilities like the NYC Department of Sanitation or the Fire Department, Police departments,and othe municipalities, a variety of other Defense contractors, Large Structural, Mechanical, Piping contractors and many other midsize to large size manufacturers in the New York Metro area.

In fact, before inverters came out into the market large scale, 3 phase primary input was the preferred option for these types of companies because, the equipment required less KW draw in order to run the equipment, and power factor correction was another option that was widely preferred if the option was available... In other words, it cost these companies more to run the equipment as often as they did using single phase as opposed to 3 phase, and they did see it in their utility bills of course, except for the utility companies - that is!!! ;)

Btw, my name is spelled: Henry - not "Henery" ;) My friends call me "Hank!"

Respectfully,
Henry

By DaveBoyer (*****)

Date 08-29-2007 04:46

Henry, sorry about misspelling Your name. Do You recall any model numbers of Miller or Lincoln machines with 3 phase primary and single phase AC secondary output? I am curious as to how they did it, and would like to look up the schematics on the Manufacturers websites.

By ssbn727 (*****)

Date 08-30-2007 09:11

Hi Dave!
It's a possibility that I either misled you into thinking or that you might've somehow misunderstood what I was alluding to in that there are power sources such as the one you described... Please let me attempt to clarify what I was alluding to...

These power sources run on 3 phase primary and produce 3 phase output that's rectified via full wave rectification using diodes, SCR's, thyristors, and are further filtered via capacitors and resistors resulting in a very smooth almost straight line of DC output when one uses a oscilliscope in either polarity with very few ripples between each of the individual sine waves that are spaced very close to each other so that there's very little chance of "self rectification" for any noticable amount of time when compared to single phase output. :)

An improvement to this was the introduction of true square wave power sources in which one could in essence, customize the shape of the sine waves in order to further smooth out the dc or ac ouput so as to eliminate the problems encountered with single phase transformer rectifier type power sources...

Another added benefit of inverters was the fact that they required less draw (KW) from their primary input to operate, and if an out fit was running 3 phase primary input, inverters did offer savings in KWhrs to operate power sources of equivalent current output by sometimes 30% or more in some locations.
I hope this info clarifies any misunderstanding that might've occured. ;)

Respectfully,
Henry

By Lawrence (*****)

Date 08-27-2007 05:46 Edited 08-27-2007 05:51

Alan

You ask about :

"I ask this based on the fact that if the hi-frequency isn't adjusted or working properly the arc will be lacking stability and possibly exhibiting altered cleaning action. I know I'm being a die-hard here so please forgive me."

Your spot on... This phenomena.. where the arc does not switch back and forth cleanly between polarities is call *rectification* A sputtering AC arc, sounds bad, welds bad, inconsistant cleaning. So we were talking about the same thing.. I just threw down the 50 cent word :)

I suggested in my first post that the HF intensity might be increased if the torch cable was longer than normal or if rectification was a problem... Sometimes corrosion or loose connections will also make HF response less than great and the intensity may be increased to deal with that.

By aevald

Date 08-27-2007 05:55

Hello Lawrence, and once again thank you, my understanding of certain terminology is lacking and your response here has cleared that up for me. This has indeed been a good thread, I feel as if I have learned volumes about the exact purpose, reasons, effects, and circuitry involved with hi-frequency. Thanks again and regards, Allan

By ssbn727 (*****)

Date 08-27-2007 07:52 Edited 08-28-2007 09:37

Hi Allan!
To answer your question:
I have another question for the two of you. A while back and I can't actually remember why, I took the leads on a syncrowave 250 and switched them(moved the torch to ground post and moved the ground to the torch post), I then tried to weld in the AC mode as normal, it was a catastrophe. The arc was all over the place and I couldn't get a puddle to save my tail end. In my mind this shouldn't have had an effect on the welding as it was being done with AC current, yet I also surmised that the hi-frequency portion of the current was being fed through one of the posts in particular and that by my changing the configuration of these I had somehow upset the proper operation of things. Just wondering what the explanation for this would be?

When read your query I could'nt agree more with what you surmised and yet you were also asking for an explanation as to why it did'nt work so here goes: As you said the hi-freq is fed through one of the posts that has the High frequency transformer connected to it, and this would be the "torch" post... When one switches the work cable to the "torch" post and the torch to the "work" post, the High frequency is fed through the work cable that's connected to the "torch" post... The high Frequency "Superimposed current which is btw, separate from the welding output current, will end up being delivered to wherever the "work" clamp is connected to in your configuration! In effect causing as you stated: "it was a catastrophe. The arc was all over the place and I could'nt get a puddle to save my tail end."

Hopefully, this may satisfy your query Allan ;)

Also, on a Synchrowave - if your balance control is'nt set right, then that could also be the cause of an erratic, unstabile arc... To correct it all one would have to do is to adjust it accordingly to get the desired arc characteristics.

Finally as Tommyjoking mentioned, set the high frequency adjustment to the minimum setting allowable so that one does'nt put unecessary stress on the Hi-freq transformer or the hi-freq capacitor because if it's set too high the transformer has to work harder and the capacitor has to discharge at a faster rate which if it's not designed to do so when compared to capacitors specifically designed for fast discharging, the end result would be premature failure to either of thse components and/or the high frequency contact points pitting prematurely, and therefore loosing the desired spark gap for proper generation and transfer of high frequency. ;)

However, unless one troubleshoots the situation properly then there could be many causes to the problems one may encounter when attempting to diagnose unstabile or erratic arc characteristics. As larry mentioned in one of his responses that a loose cable connection could also be the culprit as would a number of other conditions not directly connected to the High frequency circuit. ;)

Here's the Generic owner's manual for the Miller Synchrowave 250:
http://www.millerwelds.com/om/o353u_mil.pdf
If one looks at the shematics for this power source, one can if they can interpret electrical schematics that the high frquency transformer is connected to the torch post as Allan surmised ;)
Hope this helps!!! ;) ;) ;) Btw Dave, you are correct in the Dialarc HF not having a High Frequency adjustment dial. ;) Here's the Generic Owners manual with the schematics:
http://www.millerwelds.com/om/o315u_mil.pdf

Respectfully,
Henry

By ssbn727 (*****)

Date 08-27-2007 09:31 Edited 08-28-2007 09:38

Hello again gentlemen!

Here's what I got from my older Lincoln GTAW guidebook and hopefully Larry will contribute his Miller version or one can go online to the Miller website, look for the "improving your skills" link and one should find what they need ;)

Anwho, here goes from page 11, 2.7 "Rectification and Cleaning action on AC:

"As mentioned before, when welding aluminum or magnesium with AC, an unbalanced waveform will occur because the hot tungsten electrode will emit electrons more readily than the aluminum oxide or magnesium oxide metal surface. This results in more current flow when the electrode is negative and will provide more heat in the weld pool where it is needed, The smaller amount of current when the electrode is positive is acceptable provided sufficient current flows to provide adequate cleaning of the surface. The lower the current flow also means less heating of the tungsten electrode.

During AC GTA welding the current flow goes to zero twice every cycle and the arc must be restarted twice every cycle. When the electrode becomes negative, restarting occurs readily, but when the electrode becomes positive, restarting may be delayed resulting in lower current. If the current does'nt start on the positive half cycle, complete rectification occurs and there will be no cleaning action.
Continuous high frquency superimposed on the AC will assure that the arc is restarted early in each positive half cycle to provide the cleaning action and minimize the unbalance. Some newer, more advanced power supplies provide a square wave AC in which the voltage changes from maximum negative to maximum positive rapidly enough that the ionization of the arc remains and current will continue to flow on each reversal of voltage. Continuous high frequency is NOT essential under these conditions.

The amplitude of the negative half cycle can be increased to increase penetration while the amplitude of the positive half cycle is reduced. To increase cleaning action, the amplitude of the positive is increased while the amplitude of the negative half cycle is decreased." Hope this helps also!

Respectfully,
Henry

By aevald

Date 08-27-2007 13:04 Edited 08-27-2007 13:34

Hello Henry, thank you for the response, I have learned a great deal from Lawrence, Dave, and you from the replies to this thread. I would guess that many others, if they have been following this, will have picked up a bunch of good information as well. Once again thanks and regards, Allan

By Tommyjoking (****)

Date 08-28-2007 03:08

It is a narrow subject but I think this has been well covered by all involved in a short amount of posts.

By ssbn727 (*****)

Date 08-28-2007 09:40

I'm glad you approve Tommyjoking! :) :) :)

Respectfully,
Henry

By 803056

Date 08-28-2007 14:22

Now that the experts have given their advice, I will add my observations.

When welding aluminum, the self rectification mentioned by Lawrence also causes an imbalance of the current and voltage on the half cycle. The old timers used to add a car battery to the
"Heliarc" circuit to overcome that voltage drop. I first noticed this when I was about twelve years old while my father and I were making one of our frequent visits to a local welding shop to have a piece of broken farm machinery repaired. I asked the welder why he had the car battery hooked to the welding leads. The explanation was simple, "It welds better."

It always intrigued me why "it welded better" with the battery connected and I finally got my answer many years later. The battery "added" several volts to the half wave of the AC cycle that sees a drop in voltage due to the "self-rectification" experienced when welding aluminum.

Now, some GTAW machines have "balance control" on the control panel to add a few extra volts to overcome the self-rectification of the aluminum. Proper wave balance also prevents the overheating of the transformers and leads to their early demise.

Jump ahead twenty plus years, while I was qualifying a couple of welders on aluminum pipe, I had two welders using exactly the same machine settings on the same machine models. One was having no difficulty penetrating the root face to achieve complete joint penetration. The second welder couldn't penetrate the root face to save his life. The voltage and current were exactly in the same narrow range. I scratched my head and figured "something is different, but what?" Then I checked the "balance" knob. One was set near maximum penetration, the other near maximum cleaning. When I reset the balance control to 60% maximum penetration, the second welder had no difficulty in penetrating the root face.

Now, let me hammer the codes, wave balance isn't listed as an essential variable. Clearly, my experience is that it does influence the ability to "penetrate" the aluminum base metal where self-rectification must be considered, yet it isn't even listed as a welding parameter by any of the welding standards I've used. A simple reminder, the codes list the minimum requirements that must be included in a WPS. We, as the experts, have to include those parameters we know influence the welding operation. Why be one of the many consultants that write a WPS that meets the "minimum code requirements" and is just one more piece of useless paper the welder will ignore? Write the WPS for the end user, the welder. Give them the information they need to do their job properly.

Every new machine made comes out with new bells and whistles. We have to learn how they interact and control the welding cycle and waveforms. I call it job security!

As always, there is some excellent information here.

Best regards - Al

By Lawrence (*****)

Date 08-28-2007 15:31

Well spoken Al,

This gives me several thoughts...

As to hammering the code..... I suspect this is one of the reasons that D1.2 does not have any pre qualification language... Everything must be proven... Although I do think a place for AC balence is apropriate on a GTAW WPS and I don't think it would be wrong to incorperate it... One may exceed the code and still be compliant.

Lets Hammer the vendors too......... These folks selling inverters with balence control that goes beyond 90% EN often suggest in their literature that good welds (smaller fillet sizes, faster travel speed, etc) can be produced on aluminum with AC balence settings skewed dramatically toward max penetration.... Well all I have to say about that is that the proof is in the pudding and I don't care how you improve your surface prep, or how high you adjust your frequency in Hz, you are not going to get sound, code compliant or X-ray quality GTAW aluminum welds with 85 or 90% EN...

People pay 5 grand or more for inverter GTAW machines when 95% of the Aluminum GTAW work out there can be done with code quality and equal production rates on a Synchrowave, Percision Tig or any other Transformer Rectifier with normal balence control. (normal balence with a transformer rectifier being between 45% EN Max cleaning and 68% EN Max penetration.

By 803056

Date 08-28-2007 16:04

Hello Lawrence;

I agree that the KISS principle still works and all the bells and whistles can't make up for inexperience or good welding habits.

However, I qualified several welders on aluminum a while back. They used some new inverters (Miller Dynastys) that really impressed me. They did a great job and every one of the welders passed on their first try. Very unusual when qualifying on aluminum. I would have put money on the line against them passing. They wiped the plates with alcohol soaked rags and started welding. No wire brushing at all to remove the surface oxides. The samples (6061) passed the bend tests with no problems or hints of porosity.

Welding never fails to surprise me.

Bes regard - Al

By Lawrence (*****)

Date 08-28-2007 16:50

Al,

Inverters are awsome... I love my Dynasty and I was a beta tester on Aerowave too, It has been fun exploring what they can really do. We have the new Dynasty 350 hybrid on order, I test drove one in Appleton this summer, and while I thought the touchpad was excessively complicated, the capabilities are outstanding.

I'm just saying that in the end, most of the work done with those Dynastys may be done with settings that could be attained with a synchrowave at half the cost.

By ssbn727 (*****)

Date 08-30-2007 09:20

Hey Larry!

Speaking of Appleton, WI - home of Miller Electric... Have you taken any of the "repair person' courses there yet? I did back in the early Eighties, and I've been wanting to go back for some refresher courses.
I had a great time while I was there, and will always remember their hospitality! :) :) :)

Respectfully,
Henry

By Lawrence (*****)

Date 08-30-2007 11:21

Henry

Actually I'm a bit intimidated by Lectricity....... so when it comes time to fix stuff that requires the case to come off... I depend on the repair budget........ Maybe someday.. prolly not :)