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I have just been tasked with transitioning our shop from Standard CV GMAW to Pulse GMAW. 85% of our welders have Pulse capabilities, but almost all of the operators only use the Standard CV settings. we have only Lincoln electric welders 50% being powerwave 455, 10% powerwave 655, 5% IdealArc 400, and 35% S500. We are slowly replacing the old PowerWaves and IdealArcs with the new S500s. Does anyone have any advice on how to make a smooth transition to Pulse? most of our machines have the capability of locking in the pulse mode.
Thank you in advance.
Rots of ruck!
No two models of GMAW use the same pulsing programs.
Personally, I qualify the PQRs for pulsing on a specific machine model. If the client buys a different model or from a different manufacturer, we qualify the WPS on the new machine.
The welders are also qualified using the specific welding machine and the specific qualified WPS.
It is nearly impossible to set up two different machine models that can pulse with exactly the same parameters unless you use a multichannel oscilloscope. Few fabricators have the instrumentation or ability set up different machine models to run the same when trying to pulse.
Best regards and my deepest sympathy: Al
Thank you for your sympathy Al, I am not enjoying this assignment.
Very respectfully,
Alex
Lemme say this about that.
Lincoln can produce a pretty trustworthy readout on voltag and amperage from right inside the S500 feeder.
My opinion has softened here over years.
Current, Voltage, and Travel speed are all measurable with a new Lincoln Platform. You can set your "trim" value to read as voltage and you can set your WSF value to read amperage both during the weld and as an aggregate after the weld.
I agree with Al that the scope may be necessary if you want precise readings of waveform values.. But I don't see that as necessary for D1.1
If the Arc sprays (open arc and dropletts smaller than filler dia.)
If the Arc has CV properties, (arc remains the same length when CTWD is slightly moved)
Than it is GMAW Spray Transfer and a prequalified process..
This view was born of harassment of Lincoln engineers and D1 committee members who tell me that is the way it is, even if the power supply is CC/CV.
While I strongly suggest that *Production WPS's* have full control of all "Weld Mode" "Arc Shaping" "Crater Fill" "Hot Start" or any other sequential or arc adjusting subroutines........ I don't see it as being that big an issue as far as compliance. (Depending on with whome you must comply)
So your old and new Lincolns (455 vs S500) CANNOT run the same pulse programming... You can set each of them to deliver Current and Voltage readings to their LED readouts at the feeder... Furthermore you can LOCK those feeders to your WPS requirments of current and voltage..
I dont think I'm arguing with Al here, because he is always right and I have been proven wrong all too often... But I might be suggesting that there is a way to comply via D1.1 without running a PQR for every generation of Pulse Lincoln power supply....
BTW..
Just to be nosey
What performance improvement are you expecting from your S500 GMAWP platform?
I have a number of S500's and am considering more... And I have my own Ideas about what they can and can't do as far as production improvements..... in both manual and in automated GMAW....
Just want to hear about what you are seeing against maybe what the sales folk suggested you would see.
If ya know what I mean :)
I am very Impressed with the S500's that we have aquired so far. I love the PrecisionPulse for welding verticle up, i find the RapidArc also works well for our flat position, high travel speed applications reducing splatter significantly. And the Pulse mode also produces a significant reduction in spatter as compared to standard CV. That being said was it "heaven sent" like we were led to believe... no, but a very impressive machine overall.
Alex
Unfortunately our S500's are way under utilized. There are so many bells and whistles on these machines it is incredible but unfortunately they are currently being used only as standard CV machines. My goal is to change that. In the near future I would really like to start getting into the CheckPoint Production monitoring capabilities that are being wasted at the moment.....
very respectfully,
Alex
Being the geek that I am, I have to ask what might be available in terms of data acquisition loggers? Maybe there is a way to capture the welding parameters and export the data to a spreadsheet to calculate heat inputs. Physical tests from machine to machine may still be necessary but a scheme like this might offer a leg up in terms of getting different machines closer to the "same" nominal WPS. This means spending more money though. It goes without saying that the most practical route is to just buy the same equipment across the board.
I'm sure there are commercial solutions, though they may not be marketed toward welding equipment, but I have done this with a data acquisition system and a current sensing coil. If you're slick you might be able to use the current sensing coil in the power supply (if there is one), but it's pretty simple to build one if you're electrically inclined. Some of the advanced Fluke meters might have a capture function and a data output. It'll be slower than with a proper DAQ and coil, but it's better than shooting in the dark.
Being that heat input is a derived number that's really best as a procedure control variable, it really falls in to the category of "irrelevant" when trying to get pulsing machines to match. You're in arc physics land when doing this, so as Al points out, the specifics of the waveform become the dominant parameters, not heat input.
There is code compliance and there is real life.
ASME has a method of obtaining code compliance when using pulsing power supplies, but it is a smoke screen in my opinion.
The meters on the pulsing power supplies are an average value of the parameter shown. They do not indicate the maximum or the minimum values of either voltage or current. Using the meters provided by the manufacturer one can calculate the heat input, but that does not translate nor does it provide assurance of the specific transfer mode used.
It amazes me to no end that contractors are surprised that using the "same" parameters on one machine does not produce acceptable results another machine.
Considering only the average values of the welding parameters is neglecting to consider the influence of welding variables such as the shape of the waveform on the mode of transfer. The frequency of the pulse can easily make it difficult if not impossible to determine the mode of transfer.
While I have no bias regarding the use of pulsing, I am firm in my belief that the only way to truly know what is happening in the arc is to use a multichannel oscilloscope. The likelihood of a welder using a typical WPS to set up more than one model of pulsing power supply is hardly a realistic expectation. Most pulsing power supplies are preprogrammed by the manufacturer to overcome the difficulties of setting the machine for actual welding. Prior to the advent of preprogramming, few pulsing power supplies were used to their full advantage. Considering the fact that the manufacturers have not settled upon a singular approach to what pulsing characteristics produce the most desirable results, it is little wonder that a preprogramed machine produced by one manufacturer is not the same as a preprogramed power supply produced by a different manufacture. A WPS listing the program number that applies to one power supply is not applicable (read "totally useless") to a power supply model sold by a different manufacturer. A WPS that lists the peak and back ground parameters, up slope, down slope, duration, frequency, etc. is more than likely "penciled whipped" unless the individual writing the WPS had an oscilloscope at their disposal and must use the same to set up a different machine.
I must say, it does complicate matters for the contractor well as the CWI or other person tasked with setting up and monitoring welding operations that employ pulsing power supplies produced by several different manufacturers.
Lincoln Electric doe or at least they did produce a pulsing power supply that could be connected to a laptop computer with the appropriate proprietary program to operate as an oscilloscope to monitor and set up their pulsing power supply. It is a good start that should be considered by other manufacturers.
Best regards - Al
If the arc is demonstrable as having a CV characteristic
If the current is measurable (even if averaged) from point A to point B
If the voltage is measurable (even if averaged) from point A to point B
If the arc is open (readily observable)
If the droplets across the open arc are smaller than the wire diameter (readily observable)
Why is the above not Prequalifed GMAW spray transfer?
Why are the above elements not usable to produce a PQR that is D1.1 compliant?
Just askin :)
Who said pulse spray transfer isn’t prequalified? That being said, let’s not forget the conditions of prequalification includes the requirement that the power supply must be a constant potential power supply. Some pulsing programs produce the characteristics of a constant current power supply because they have variable inductance that can vary during the welding cycle. Then there are the annoying constraints listed in Table 3.7 that has to be met if the WPS is prequalified.
My position is now and has been that the average arc voltage and average amperage is not sufficient to ensure consistent weld quality when applied to two pulsing power supplies from two different manufacturers.
Do I understand your position is that the only thing that has to be the “same” when welding with two different pulsing power supplies is the average arc voltage and average amperage? That sounds like rhetoric from a sales person or a fabricator trying to convince the TPI separate WPSs are not needed for different pulsing power supplies.
Best regards - Al
I'm just trying to make this a good conversation that causes you to make even more good conversation :)
I'm saying that my opinion is that any Miller, Lincoln or ESAB, box stock GMAWP power supply that has been produced in the last ten years can produce Spray Transfer GMAW to a prequalified WPS that is as tight as a 20 amp (25 ipm) and 2 volt window. (Assuming 045 wire and a standard shield gas)
I'm still not convinced that it is a D1.1 compliance requirement to run seperate PQR's for every upgrade or slight change... Or even a change in brand.
If you want to generate seperate WPS's for each model or brand... Good and fine.. But If a PQR was involved I question the need to do another if the WPS's can be written within the scope of the original PQR's
The latest GMAWP's are running something like 16 or more values on both CC and CV prolly ramping to high pulses approaching 500a but with durations measured in Mhz.... I doubt your scope could keep up. When they are pulsing at that kind of speed (chopper technology and the like) maybe... Maybe "maybe".. an average is a better way to make the assessment?........ I'm in the kiddie pool and you're in the deep end here... Just a few thoughts
Edit.... I don't have a position... Though I may have to take one someday soon :)
PSS: I hope the track of this discussion is helping the OP and his thread rather than diverting it...
I recommend qualifying a new WPS when the client purchases a new pulsing power supply that is different from the one they are using and they do not meet the requirements of prequalification. There are too many variables involved to assume one model runs like another. Most pulsing power supplies are preprogrammed. Different manufacturers use different programs and there is no easy means of determining what the pulsing parameters are.
The WPS, whether it is prequalified or qualified by testing, should provide direction to the welder. It should give sufficient information to allow the welder to set the machine and be ready to weld. I don't believe listing the average arc voltage and average amperage is sufficient to ensure the different machines will achieve predictable results. To add to the confusion the terminology used by manufacturers is not standardized. It is like describing the difference between an apple and an orange to a Frenchmen and a Brazilian in Swahili when neither speaks the language. With that in mind, writing a single WPS that is applicable to several different model pulsing power supplies is difficult to say the least.
I don’t claim to be an expert on the subject of pulsing power supplies, but I am familiar with trying to get two different model pulsing power supplies to run the same. It isn’t easy to do with one WPS.
Best regards - Al
Thank you all for your input, but you are thinking entirely too hard. It is not the WPS or PQR that concern me I can handle that, it is the 250 welders on the floor who do not know how to use Pulse. I am just trying to gain some insight from you extremely knowledgable folks on the steps, potential obstacles, and maybe some training material for this transition. I realize that there will be a learning curve for the guys on the floor, and of course this change will be resisted, and will require a paradigm shift (“this is the way we have always done it, why change now”). I feel that we must have some sort of training, I was wondering if any of you have any literature, or training modules, or advice geared towards the operator which we could utilize to edify the operators on the process and its benefits. I thank you all for your time and patience.
Very Respectfully,
Alex
Alex,
We share the training issue.
My strategy was to buy a couple of S500's and do trials myself.
All of our work is done flat or horizontal which makes life easy.. All spray GMAW and all on structural steel in a manufacturing environment on steel from 10 ga. to unlimited thickness.
My trials told me I could make every weld in our plant within a window of 260 to 280 amps and 25-27 1/2 volts.... This is using rapid arc and measuring current and voltage with a tong Fluke meter at the gun and at the output lugs... (sorry Al, no scope) The Fluke readings pretty much exactly matched the output meters built into the S500's 10M feeder... I was impressed..
The training consisted of breaking my welders habbit of "whipping" their mig guns and running at wire feed speeds at the top of a too generous WPS. This habbit needed to be broken regardless of power supply... It was just my leverage to get it done NOW!
My weld is my signature
I *Smashed* this old Stickwelding cliche and now the intent is for every weld that rolls out on the trucks to look the same.. Like caulking... No more stupid, time wasting, volume wasting, distortion causing, bonus stealing, ripples!
For the work I do, the arc shaping features were not making anything better, but I could see their value in an automated world. So they are locked out.... EVERYTHING is locked out buy what I want them to use... (a very tight window and only a single schedule)
I have welders measured in the hundreds as well... Many don't like change... But back to the story.
Oversized Whipped GMAW is evil..... putting down a 1/4" fillet where a 3/16" fillet is called out is a 78% waste in weld volume and arc-on time.... A 5/16 weld placed in a 3/16" call out is a 180% waste.........
Overwelding is our enemy!
I see no "production" advantage in my type of structural welding with GMAWP... A $5000 CV powersupply with a good feeder will spray spatter free fillets just as well as a $12,000 Pulser. But the level of fume generation is much lower with GMAWP and on a Multi-shift operation the inverter draws so much less power that it can be justified that way alone.
The "Rapid Arc" CAN make a faster fillet than traditional spray... So what.. My welders can't move that fast for 12 hours a day and 6 days a week. A robot can! But that's not us.. We have fitup issues, mill scale and every other thing that makes a day long to deal with... I prefer to look at effeciency and obedience to weld size to be the key rather than speed measured in linear inches per minute.
If my welders make the correct size weld, my plants gain about 60% capacity just by making the right sized weld where they were overwelding before. A very tight WPS and close supervision by people who know what they are looking at is the real key in my opinion.
Off the soapbox and back to the question.
I don't think the GMAWP runs much different at all... 10-15 degree push.. 1/2-5/8 inch stickout (CTWD) is less critical because GMAWP via the S500 is synergic. It sounds different, that's all.
Edit:
Work Clamps!!!!!!!!!!!
Work clamps and power connections must be PERFECT... Those old connections tend to work harden and the copper threads begin to break..(added resistance) this causes the connection to get warm, more brittle wires, next the connection/lug/clamp gets hot.... The GMAWP synergic properties... The stuff Al Measures with his scope... These waveforms need to be controled by an adaptive feedback system... When those work leads (ground clamps) are in poor condition the GMAWP power supply is not getting clear communication with the weld and it needs it. It will also cause the gun to smoke contact tips much faster than normal.
A small thing that can cause big troubleshooting issues.
I've skimmed through the posts and I don't believe the most important question has been asked.
What do you do that makes you think you need pulsing when you have been using standard CV for so long?
I love you man!
I spoke to this as far as my own opinon goes in my last post.
But would like to hear what the OP thinks.
Perfect Question Sir!
You hit the nail square on the head!
The most important question is sometimes avoided by the manager that should be asking the question.
Al
All I gotta say is this... Have you visited Ed Craig's Weld Reality web site which has some interesting information & observations regarding Pulsed MIG Welding Basics as he put's it yet? Please do because it will be enriching as well as enlightening if you haven't already...
Here's the link and after you read what he thinks about pulsed GMAW, let us know what you think okay? Btw,
WELDCOME TO THE WORLD'S GREATEST WELDING FORUM!!!
http://www.weldreality.com/pulsed_welding_fundamentals.htmEnjoy!
Respectfully,
Henry
It looks like Ed and I agree on several issues related to GMAW pulse transfer.
It interesting that I visited one of my clients on Friday to qualify a new welding procedure. They are welding stainless steel with new mechanized system using Helium, Argon, Carbon Dioxide mix. They already have a qualified WPS using SG-AC-5%.
I asked their QC manager why they were using the tri-mix when they already have a qualified WPS. His response was "That's what the vendor suggested."
I told him to at least make a sample using the SG-AC-5% before going through the expense of qualifying a new WPS.
He came back to the conference room with samples removed from the first trial run using the existing WP. The visual results and the macros of the samples were better than what they had been getting using the tri-mix. The bottom line is they stayed with the existing WPS and have improved results from the get-go. By the way, no pulsing required.
Best regard - Al
By Phaze 
Date 10-22-2013 04:28
Edited 10-22-2013 04:31
To be honest the pulse is just an added bonus, my main goal in this transition is to lock in six settings. Right now I have a very similar problem to Lawerence, much to generous WPS's, and guys who just won't follow them (story for another day). We use dual scheduale guns, my plan so far is to lock in three different "hot" settings, two "cool" settings, and one out-of-position setting (most guys keep a "hot" and "cold" schedule programmed). The part that I have to play around with is finding those six settings that will cover all 4,300 something jobs we run. Another reason I would like to use pulse is we have these very impressive (and very expensive) powerwaves that are not being used to their potential. Before I landed this job I was a production welder, and I have experienced the benefits of GMAW-P first hand, especially Lincolns variations. The Experience I've had with these machines has made me a believer.
Very respectfully,
Alex
You need to push practice and training on Co time which is the problem. Trying to get to a few settings for everyone is treating the welders like machines. Everybody is different I run 10-20% hotter than everyone else because I can control it and others need to run even slower to others to prevent problems. Pulse is nice for some things and great for others. You need to set up class time with the welders and machines. The other instructor at my shcool got a free $6000 Miller Dynasty because the fitters couldn't get it to power up(3 menu screens) and threw it in the trash. You can put the coolest toys on the floor but if nobody knows how to use them they will not be used. I have tried for years to get companies to see the value of a qualified weld manager and training/verification before sending people/machines to jobs. They would rather see $10-100,000 in trash in the air than take 3 hours to make sure the person/machine are up to the job.
With all due respect
If I have hundreds of welders to manage, I don't care if one guy can weld 20% hotter...
What does hot even mean? More WFS More voltage...? Baah!
Every welder I've ever met that says they can "handle more heat" just makes bigger welds. You think your working faster, but your just making bigger, more time consuming welds, adding distortion and costing me money. The feel like they are going faster, but they are only working harder to do less.... A stop watch will prove this out time and again.
Most guys can make a small weld with a high WFS rate... But they can't do it 11 hours a day and 6 days a week.. So I don't ask them to... Reasonable rates will get the linear inches per minute that makes quality and money.
Production welding is science NOT art... Lock down parameters... If the process control is good, it worksI want quality welds that are the size the drawing calls for and nothing more.... If I lock in the parameters on voltage and wirefeed speed.. If the welder makes a 3/16" weld... I know exactly how fast he is traveling.
GMAWP for out of position welding with steel and solid wire? Only if it is very thin stuff < 1/8" Out of position GMAWP is the slowest thing I've ever seen..... FCAW with .045 E71T-1 can run vertical at 400 inches per minute with straight C02 and 450 with mixed gas... GMAWP can do maybe a quarter of that.... Stainless and aluminum are another matter.
I'm with Ed Craig on this... The ONLY benefit I see from GMAWP on D1.1 thick steel is a lower fume generation advantage, and even the stats on that come from the guys selling the things.
Welding Journal February 1992 "Inverter Power Sources Check Fume Emissions in GMAW" By Bob Irving Features Editor of the Welding Journal and input from EWI. I can imagine in two decades alot has been improved on.
Most GMAW-P power sources have/are using a constant current output machine to achieve the peak amperage/current pulses. To keep the setting "simple"; have the welders #1 Select the appropriate GMAW-P program for the metal, wire & diameter & if required shielding gas used, #2 Set the wire feed speed (hotter/colder) #3 Adjust the arc length (longer/shorter) "Trim" setting and #4 Adjust the arc cone width (narrower/wider). Of course gas, gas flow rate and wire feed speed needs to be set at a value to achieve spray transfer. Weld cable sizes needs to be sized for peak amperage/current pulses and gas hoses must be sized to provide the volume of gas needed at a given flow rate.
Max
Pretty much everything off the shelf for manual GMAWP these days has both CC and CV "behavior" Meaning that when the CTWD changes slightly, the current value will remain relatively the same and so will the voltage (arc length).
Fronius has some excellent Youtube demonstrations of the operator changing the CTWD during a weld, while keeping at the same time a steady current input at the weld and showing no visible change in arc length.
There are so many layers of dwells and durations in modern synergic GMAWP, all controlled internally that it's hard to grasp. But the controls are far more simple for the operator... No multi knob pendants (optima)...
While there are subroutines to adjust the "cone width" on the new stuff... They are synergically integrated so that you don't need a slidrule or calculator to predect necessary changes to the other layers of dwell and duration.
In most cases GMAWP operates as advertized... Something that was not true in the 1990s :)
Yes indeed the industry has come a very long way in GMAW-P in 5 decades from SCR technology with only 60, 120 and some even had 180 peak amperage pulses per second. This technology was developed to weld out of position with a spray transfer.
Launch the inverter technology & this industry didn't know what a good pulse arc was so ~ Set a wire feed speed, set a peak amperage value, set time (in milliseconds) at peak amperage, set peak amperage pulses per second, set a background amperage, & set a peak and background voltage. With enough time; synergic controls were developed and all became more simple.
A long ways from the transformer rectifier cv machines with a wire feed speed, slope (volt/ampere) control, voltage control and inductance control. No line/primary/mains voltage control and if that changed. It required the resetting of all controls as needed to get the optimum gmaw-s arc.
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