CMT, STT and RMD

By Lawrence (*****)

Date 03-24-2019 15:33

Hey North!

Yes and No :)

Much depends on what you need.

Fronius is miles ahead in capability, flexibility and automation. But not everybody needs that extra tech.

If you are looking for open roots on stainless and carbon pipe, I think they all can perform equally well.

So much depends on your production demands.

What are the tasks you require?

By Northweldor (***)

Date 03-24-2019 19:08 Edited 03-24-2019 19:14

Thank you for the answer, and you are correct about Fronius, since, according to an excellent article by TWI, Fronius CMT is the only one to modify the feed system, as well as digitally controlling the power source. Here is their list of current systems:

" ... Such systems include the Fronius Cold Metal Transfer (CMT), EWM ColdArc®, Lincoln Electric Surface Tension Transfer (STT), Miller Regulated Metal Deposition (RMD™), Kemppi FastROOT, Jetline Controlled Short Circuit (CSC™) MIG, Daihen Corp. Controlled Bridge Transfer (CBT), Merkle ColdMIG and ESAB QSet™ processes...."

and apparently, only Fronius uses the wire retracting feed system. All the others have wave form variations in the way their digital controls apply, but are essentially doing the same thing!

My only need is feeding my curiosity about welding, and I just found this article this morning. Here it is:

https://www.twi-global.com/technical-knowledge/job-knowledge/mig-mag-developments-in-low-heat-input-transfer-modes-133

By Lawrence (*****)

Date 03-25-2019 12:51 Edited 03-25-2019 13:02

The Fronius for sure is more complex... CMT & CMT-Pulse do a lot more than just open roots.   They are designed for high speed sheet metal work, out of position combination Spray/Short-circuit waveforms and much more...   It's really apples to oranges when comparing to RMD and STT which are "primarily" designed for open roots..... STT and RMD are also branching out with different styles of waveform as well, so I wouldn't leave them out of the conversation.

Miller actually does have a GMAWP Aluminum specialty power supply and feeder (AlumaFeed & AlumaPower) that has synchronized the Wire feed to the wave form in order to provide a "rippled appearance" with a straight forward progression... This is accomplished by the Push-pull assembly changing speeds as the waveform also goes up and down... I've used a demo/beta of this back in 2013 and it performed very nicely... I can only assume it's even better now... Very big in the shipyards up in Wisconsin.

Also the Fronius "wire retract" gun assembly is complicated and cumbersome..... In a fast paced manual fab shop, it would take a very high level of periodic maintenance (PM's) to keep the system working up to snuff...   It's heavy and has an "in-line" feed assist drive system in the middle of the whip.... It works like nobody's business, but is tricky to thread and keep ship shape.

Story Time:    When I was teaching at the tech college, I had a good relationship with the Fronius national rep who was not far away...   I invited him to come and do a demo for the class with the CMT and CMT-pulse on some aluminum.....   The VP of the college was for some reason hovering nearby so I invited her to put on a jacket and hood and watch the new European Technology being demonstrated....   She was blown away by the unit and by the presenter and asked me if any of my current equipment could do the same thing... I said "nope" and she bought one right there on the spot....    Educrats and salesmen...   Some days things just go your way eh?