TIG Pulser for Miller 180SD

I've been putzing with a design for an add-on pulser for my Miller 180SD
TIG welder at work. After 3 years, on-and-off (mostly off), I've finally
got a working unit. I posted it under "TIG Pulser" on the Dropbox:
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I finished it today, so I can't give you any long term use information.
But, it seems to work as designed.
Many thanks to Gary Campbell, Ray Sommer,....and especially Ernie
Leimkuhler for his willingness to share all his welding experience with us.
Ken
Reply to
Ken Moffett
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Looks pretty cool.
Reply to
Ernie Leimkuhler
Interesting, Ken! What benefit does it provide you while welding? I'm in the Twin Cities, might I have a look at it and try it?
Reply to
Don Foreman
Nice project
Ironic though that the New miller equivalent (Synchrowave 200) has one built in now.
Or was this project more about doing it than the feature itself?
Ken Moffett wrote:
Reply to
Brent
Wow professional looking front panel, good job! I like the way you transition from Hz to seconds on the one dial, that makes sense.
Does it work well? I love the pulser on my invertig, almost makes my welds look good :)
- John
Reply to
runch
Nice of you to do all the work to post it to the Dropbox.
Dan
Reply to
dcaster
I've been wondering this also. Two per second, I think I understand: Sets a fixed interval for the heat, fill, move cycle. 20 per second? What is the benefit? That seems certainly faster than I can see.
Reply to
TheAndroid
Pulsing helps ensure penetration on thin materials without burning thru. To try it just pump your foot pedal. Not as controled as a pulser, but you will see how it helps.
Dan
Reply to
dcaster
Ernie Leimkuhler wrote in news: snipped-for-privacy@news.west.earthlink.net:
Thanks Ernie!
Reply to
Ken Moffett
Don Foreman wrote in news: snipped-for-privacy@4ax.com:
Don,
Rather than try to explain, I'll copy a portion of a posting from last Saturday from Ernie Leimkuhler, that was a copy from him responding to me when I asked exactly the same question a couple of years ago. :)
I'll get back to you later on the visit, as I've just finished it, and this is the first time I've used a pulser.
And again thanks Ernie!
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From past posts of mine [Ernie Leimkuhler]:
Pulser Description
A pulser is a device used to interrupt a welding arc. Mostly used on TIG, but can also be used for MIG. The idea is to cycle the arc from high amperage to low amperage. The metal melts at the high amperage and solidifies at the low amperage.
There are 3 settings for a pulser. 1. Background amperage This sets the low amperage and is usually set as a percentage of the main amperage. So if you main amperage is 100 amps, and the Background Amperage is set for 50%, then you Background Amperage is 50 amps.
2. Percentage of On time. This sets how much of each pulse cycle is spent at the high amperage and how much a the low level, once again by percentage. A setting of 50% evenly splits the cycle between low and high amperages. Less than 50% on On time gives a Spikier Pulse. Greater than 50% gives a Softer Pulse.
3. Cycles per second. This is the really confusing one, because it has the most profound effects. Older TIG pulsers only allow up to a maximum of 10, or less, Cycles Per Second (Hertz - Hz), but the newer Inverter TIGs allow much higher frequencies. My Maxstar 200DX goes up to 200hz.
The lower pulse frequencies are for traditional pulser use, where you run between 1 and 2 hz on the pulse. adding filler metal on every pulse or every other pulse as you progress across the weld.
The higher frequencies have a much different effect, in that they tend to make the metal super-liquid, allowing it to flow and wet out much smoother. These higher settings work very well with autogenous welds where no filler metal is added at all. These are also called Fusion or Flow welds. I also found these higher frequencies worked well for vertical welds in heavy Silicon Bronze.
Now the reason for all this pulsing is rather simple. Lets start with a piece of 16 ga steel. At 0.062" thick the proper amperage would be 1 amp per 0.001" of thickness or 62 amps, for a flat-butt weld, full penetration, single pass. You could easily TIG weld a seam in 16 ga Steel using a continuous 62 amps. However a spike of high amperage will melt the metal much faster than a low amperage, so you could weld faster at 80 amps than 62 amps, but at that heat you risk overheating the metal and causing undue warpage or burning of the steel, so you mix an interval of 80 amps with an interval at 40 amps. The low amperage interval allows the puddle to solidify back into steel, without allowing the arc to break. By pulsing the weld across the bead you get a very orderly row of rings, that give that distinct stack-of-dimes look to the weld bead. You adjust the exact pulse frequency to suit your style and speed of welding as well as the thickness of the metal. The other benefit is that over all, you have put less heat into the metal, so you have less distortion.
A smaller, consistent weld bead is often stronger than a larger inconsistent weld bead.
The more consistent a weld is the more the stresses apply along it's entire length. Any peak or valley in a weld becomes a stress point for failure to occur.
Whether you choose to add filler metal on every pulse, every other pulse, every third pulse or not at all is dependent upon your own welding style and the circumstances of the weld.
Where pulsers become bewildering is when you start messing with the percentage settings for the Background Amperage and percentage of On Time. The number of possible combinations is huge, and there is little or no guidance given in the welding world as to application.
Pro-Fusion has an excellent series of webpages with online calculators that allow you to punch in the overall required amperage you want and how fast you want to weld and it will generate pulser settings for you.
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It still gives no guidance as to when you want a Spike pulse, or a Soft pulse, but it gives you something to play with.
50%, 50% and 1.4hz, is a setting that works for most sheet metal.
All I can say is that until somebody puts out some really authoritative research showing what pulser settings are best for what combination of weld and materiel, we will all be out there experimenting on our own.
I have searched for such a book for 5 years, and given up. Hopefully some day soon the welding engineers will decide to enlighten us lowly welders.
The guideline I can give you is that the thinner the materiel the more it benefits from a spikier pulse. I have yet to find a benefit to a really soft pulse.
An example of an extreme spike pulse is that you can weld a popcan at 120 amps, as long as you set your pulser to 2% On Time and 2% background amps.
Reply to
Ken Moffett
"Brent" wrote in news: snipped-for-privacy@k70g2000cwa.googlegroups.com:
Brent,
That's a rabbit that I'm not going to try and chase. Miller seems to add new features as soon as you have purchased one of their machines. ;) The pulser was not a necessity, but seemed like an interesting project...with a potentiol practical outcome.
Ken
Reply to
Ken Moffett
"runch" wrote in news: snipped-for-privacy@h54g2000cwb.googlegroups.com:
John,
Thanks. I was happy with the way it came out. The front panel was developed in QuickCAD (formerly AutoSketch), and laser printed on transparency film. I used 3M #77 advesive to attach it to the panel and trimmed it with an Exacto knife. The photo made it look more like silk screened.
I'm just starting to use it. Never used one before, but so far it performs as I would expect.
Ken
Reply to
Ken Moffett
" snipped-for-privacy@krl.org" wrote in news: snipped-for-privacy@m7g2000cwm.googlegroups.com:
Dan,
I've gotten so much valuable information from the people on this, and other newsgroups, that I thought it was time to share a little of "my" experience. Didn't feel there was a big enough market to try and sell this as an after-market add-on, or as a kit. The circuit board was $59 for three, from ExpressPCB. I still have two left, if anyone wants one for $20. I also just realized today, that if I had cut the cord from the foot control in two, I could have used any 5-pin connector pair on the box. Oh well...I hope someone can make use of the posting. :)
Ken
Reply to
Ken Moffett
Ken, awesome job, I bet you have this feeling of satisfaction!!!
i
Reply to
Ignoramus18503
I dont blame you for that one
I havnet used to pulser yet. I dont think my good old fashioned TIG welding is up to snuff yet doing plain old welding so i'm not going to get fancy till i can do plain and reliable
But out of curiosity what model and type of connector is that 14 pin one?
a finger amperage control for out of position work would be a nice project in my books (though i prefer the pedal) and the only part that i havent stumbled across (Or thats sitting in my electronics parts pile) is that Amphenol connector.
I know Amphenol makes them but i havent found it (too big a forest of products they make to find the 14 pin welding connector tree)
But Great work on the pulser unit
Ken Moffett wrote:
Reply to
Brent
That got my attention! This project just went on my "to do" list. I probably have all the parts on hand, except maybe for the pots. Ax Man has pots.
I'd be interested in one of your PCB's if you still have any left. Most folks would do this with a PIC processor, but your linear design is clean, straightforward and very un-fussy. Probably also pretty EMI-proof, and no higher chipcount than a UP would need.
What is that block in the lower righthand corner of the schematic, pls?
Reply to
Don Foreman
"Brent" wrote in news:1163686746.277546.264250 @h54g2000cwb.googlegroups.com:
Bernt,
The connectors are listed in my TIG Pulser.txt file in thre Dropbox. They are:
The AMP/Tyco Connectors are available from Electronic Industries Inc. P.O. Box 266 Oshkosh WI 54903-0266 (920) 235-8930
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Part numbers: 1 each: AP-213571-2?Plug 1 each: AP213570-1?Receptacle 1 each: AP206070-1?Plug Shell w/Cable Clamp 10 each: AP-213603-2?Pin, 18-14, Tin, 10 each: AP-66601-2?Socket, 18-14, Gold Total (w/ shipping) $27.82
There's no magic in these connectors. They only used 5 pins. As I said in another reply, if I had thought about it I could have cut the foot control cable near the machine end and inserted any 5-pin connector pair I wanted. Then use that as the connecting point for the pulser. Even without the pulser you could do that for your finger control. Were you looking at the finger control ("tig remote.xxx") files posted in the Dropbox? Looks pretty good.
Ken
Reply to
Ken Moffett
Don Foreman wrote in news: snipped-for-privacy@4ax.com:
Don,
I still have the PCB's. The Log-taper pot was the only one I had to buy. I had been through Axman's stock with no luck. ;) I'll look through my old PO's and get you the vendor and part #.
I had thought about a PIC halfway through the developement. But the HF arc starter was blowing out the LM324 on one of my perf-board prototypes, and I didn't want to get into that noise screwing up program steps. The addition of a ground plane on a PCB and the ferrites and bypass caps on the wires entering the box solved that. So, that may be the way to go now. Though the analog verson did everything I wanted.
The block is a DC-DC converter, to get a bipolar supply (+/-12vdc) for the op-amp, from the +20volts in the welder. It needed that to drive the P-channel MOSFET into full conduction. It was a 12vdc input DC-DC converter that I already had...that's why I had to put U1 in there...to get the 20v down to 12v. I can't find one with a 12v input that has the same footprint and pinout to directly drop in. That's one of the mod's on the "Mark II" if I ever did another one. ;)
Ken
Reply to
Ken Moffett
Amazingly enough, the programmable (in BASIC) controller in my own modded welder, called Cubloc, is not burning out from HF.
i
Reply to
Ignoramus25220
Ignoramus18503 wrote in news: snipped-for-privacy@news.alt.net:
Thanks. I do feel preeeeeeeetty good about it :)
I'm working on a web page of some of the things I do for fun (and money):
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Ken
Reply to
Ken Moffett

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