Mark @ Everlast

[yomax4]

I have a MM251 as well as some Synergic Pulse equipment. Prior to the MM251 I had a Lincoln 255. MM251 inductance is set too low. Coarse and spattery even with 92/8..The Lincoln has a higher inductance and welds soft and smooth with little spatter even with 75/25. That's my only beef with MM250 amp units. If I was ever in the market for a lower end unit like a MM252, I would look for a brand that had an inductance control so I could adjust the arc and maybe even be able to do a little Stainless with good results. If you only weld steel and don't mind grinding, Then it doesn't matter.

 

[4shorts]

If you only weld steel and don't mind grinding, Then it doesn't matter.

You must be doing something terribly wrong if you have to grind a weld using a MM251 or 252. Just say'in :confused3:

 

[Scooby074]

You must be doing something terribly wrong if you have to grind a weld using a MM251 or 252. Just say'in :confused3:

+1 :thumbsup:

 

[Shield Arc]

I use to have a Linde VI-206, it had inductance control, now that was slick. I think on my Lincoln V350-Pro it's called pinch.

 

[ericher69]

An excerpt from this site explaining inductance.


http://www.twi.co.uk/technical-knowledge/faqs/process-faqs/faq-what-does-inductance-do/


"Modern electronic power sources automatically set the inductance to give a smooth arc and metal transfer"

 

[yomax4]

An excerpt from this site explaining inductance.


FAQ: What does inductance do?


"Modern electronic power sources automatically set the inductance to give a smooth arc and metal transfer"

Nice read. Next would be to define "Modern" power sources. Most "New" Transformer mig machines are far from modern. Most are 30 yr old technology. They don't automatically set the inductance, It is preset at the factory. That's why one machine can have a different arc than the next.. I prefer to go one step further and be to be able to set the inductance on my own to taylor make my own arc. Look at some of the Lincoln,Thermal Arc, Everlast and others out there. Some offer inductance control from the 115v units all the way up to the 350 amp pulse migs. Of all the "preset" inductance machines I have ever ran, Lincoln is set the most correct all things considered. ( My Opinion )

 

[yomax4]

I use to have a Linde VI-206, it had inductance control, now that was slick. I think on my Lincoln V350-Pro it's called pinch.

Some call it Pinch or Dig..Your 350 pro has it.

 

[Arc weld]

When I went to school they referred to inductance as the pinch effect on the arc. I think it mostly applies to short circuiting transfer? I don't have my books from school so can't elaborate further. Linde was always big on inductance control. Miller used to have a 250 amp MIG power source with 14 tap adjustable slope for doing other metals such as stainless. The Trailblazer 55 engine drive had a similar set up with 3 position slope control for different applications. Not the same as inductance but does change the arc characteristics. I don't know if you can go inside any new Miller machines to change inductance or not. The original MM 200 had a high and low setting. Maybe that changed inductance and/or slope? I had a 255 Lincoln and liked the way it welded too. The Lincoln V305 (3 phase)MIG machine has 2 inductance settings by changing the output stud. I did a lot of MIG root passes on vessels and pipe and for that application, I would take a conventional machine like a Dimension 452 over an XMT 304 any day. The arc is almost too smooth with the inverter. One shop I worked in switched over to the XMT's and several experienced welders had piping on their X-rays. Piping is elongated porosity and even the Miller rep couldn't explain what was causing it. I heard later it might have been from too high of volts but have never had this confirmed. Maybe there's just a learning curve and the inverters need different settings for the same result?

Why not just run small diameter flux-core or metal-core if you want more production from a 250 amp single phase machine? There's an Ed Craig I stumbled onto on a website that said the best fix is to turn the pulse off, change your shielding gas and turn your heat up. He claimed pulse caused more problems than it was worth. This may have been for robotic operation but how he said he solved most problems pulse related.

My earliest introduction to Plasma was at the tech school. They had a Linde(Union Carbide) Plasma machine that used 3 different gases. I think they said it was purchased in 1968 for $10,000! In the early 90's it was traded/sold off and I saw it in the used section at a welding supply I worked at for a few month's. Seems like Union Carbide completely let Plasma technology slip through their fingers. They sold out to Esab. They had good machines, good gas equipment, good distribution and now they seem to just worry about the gas business. Seems like they could be a lot bigger if they were interested in more area's than gas. Air Liquide is the same way. They pretty much tell you the welding side of things is just a necessary evil. They used to make some of the best gas equipment on the market too and dropped it. Now they get it made by Concoa but it's not nearly as good. Esab isn't in the gas business so focuses on the welding side. Their machines just aren't very popular in N. America. Some of the good equipment they've purchased from other's, they've changed and now it's not as popular or good as it once was. The welding equipment industry is a bit wacky.

 

[Shield Arc]

You know I'm not convinced on this pulse either. I haven't played with it a whole lot, and I can see where it's valuable with thin material. I haven't tried it yet with thick material. Now where I thought it was cool was on aluminum with the spool gun, you could get it set where it almost looked like Tig welding, but I was shocked at how many amps it took.
I have the same feelings about spray arc transfer. I could see it in a manufacturing setting where you made the same welds over and over. But even the 3-years I spent in a fab shop, I'm not sure it would be worth all the trouble to set up. Out on a bridge build, no way!:laughing:

 

[jimcolt]

That is sort of correct. Dick Couch (before he incorporated Hypertherm in 1968) worked for a research and development "think tank" in Hanover NH.....this company (Creare Inc.) did contract engineering work for anyone who wanted it. One project that Mr. Couch worked on was for Union Carbide that involved improving plasma cutting technology in the specific area of increasing torch consumable parts life. The project was completed, Union Carbide paid for the engineering work....and I suspect that project got Couch's juices flowing along the lines of plasma cutting technology. Hypertherm was founded within a couple of years after this occured.......this told to me a few years back by Dick Couch.

Esab has a water injection process that was used for years in their PT-15 torch, it used "swirl water injection". Hypertherm had a few systems using their PAC500 style torch which used "radial water injection". I suspect both were developed in the labs of Creare Inc. in the mid 1960's!

By the way.....I am the second longest term employee at Hypertherm (Dick is the longest term!) with 36 years. I lived a lot of this history, and if I need more details I simply ask the man himself!

Jim Colt

Thanks Jim Colt. We just had the Hypertherm rep. give an introduction since we are a new dealer starting Jan. 1. He was the one that told us Dick Couch worked for Union Carbide and they weren't too interested in his water injection so he left and formed Hypertherm. Maybe he offered the information to Union Carbide and they weren't interested?

As far as Thermal Dynamics, I'm going off what the box and their literature says.