Hey Henry!
I must apologize for "almost" having forgotten to provide the promised information with regard to the discussions about the definitions for Laser-Arc-Hybrid Welding on the Joint Meeting of the IIW Commissions IV and XII in Vigo Spain.
Firstly, it was - once again - a very impressive opportunity for me, to attend an IIW conference. A lot of national and international experts have travelled to Vigo to discuss the current status of the industrial utilization of:
· "Arc augmented" Laser Processes (Prof. Muneharu Kutsuna - Nagoya University Japan)
· "Hybrid Laser MAG Welding Processes" (Mr. Chris Allen - The Welding Institute England),
· "Hybrid-Welding" (Mr. Ambroise Vandewyckele - AIMEN Institute Spain)
· "Laser-MAG-Hybrid Welding" (Prof. Muneharu Kutsuna - Nagoya University Japan)
· "Laser Submerged Arc Hybrid Welding" (Prof. Dilthey - ISF University of Aachen Germany)
· "Hybrid-Laser-Welding" and Laser-Hybrid-Welding" (Prof. Danut Iordachescu - Centro Laser University of Madrid Spain)
As you certainly can imagine, there have been held some pretty fine presentations from all over the world and - what was once again impressive for me - almost all experts have used different acronyms for the process, which all were discussing about(!).
As promised, and I hope you have allowed ;-) , I have tried to start the technical discussion about the "correct" technical term(s) to be used, when talking about "LASER-ARC-Hybrid Processes". I have mentioned to having an interesting interchange with US-American Welding Experts about the question of what Laser-Hybrid-Processes really are and how to define the combination of both used processes. And, Henry, what should I say else than the truth, also the venerable experts are seriously intended to clarify this basically question to pointing the direction for a better understanding of the process. I have asked - since the presentations been held treated of course different fields of Laser-Arc-Hybrid applications - several times of what the main reasons were, to name the process within the presentation such as can be seen in the list above. As you surely can imagine all the aspects therefore sounded reasonable, but nonetheless all the fellows admitted that there is yet a lack of standardization in regard to the general technical terms for the process.
When I have asked the question: "At which distance between the Laser and the Arc we can speak of "LASER-ARC-Hybrid" or different to that only "Arc assisted Laser-Welding"?" the most reasonable answers were given by Prof. Kutsuna and Prof. Dilthey who both are admitted as two pioneers in the field of Laser-Arc-Hybrid Welding. They replied, by using the term of "common interaction" of both process-plasmas which has to be observable when speaking of "Laser-Arc-Hybrid Welding". This means, there can not be stated or defined, respectively, a specific distance between the Laser and the Arc for defining a concrete use of the term "Laser-Arc-Hybrid Welding". Mainly because - as always - the coherences, specific to the application to be carried out by using the process, are so intricate that it's hard to find even this specific value! Or in other words... the boundary conditions are "fluently" (i.e. dynamical). However, when such an interaction of both energy source process plasmas (Laser + Arc) can be observed, one can talk of having a "Laser-Arc-Hybrid Welding Process".
Finally I would like to cite some sentences coming from the greatly appreciated fellow Prof. Dan Iordachescu, written down in the conference proceedings. As you perhaps can remember, I have mentioned Dan a time ago in another post, as one of the "driving forces" on an international level for solidifying the standardization of the "Metal Droplet Transfer Classification" in GMA-Welding. In Vigo, once again Danut Iordachescu was one of the fellows who have expressed seriously the necessity for finding common valid terms or acronyms, respectively, when speaking of Hybrid-Welding Processes. Therefore please let me cite what he has written in the proceedings:
"Important development of Laser Hybrid Welding (LHW) was noticed in the last decade, following the path from research to industrial application in shipbuilding [..], automotive [..], aircraft [..] and other industries. This generic name and concept is widely understood as combination of two classic processes: GMA Welding and Laser Welding (LW), respectively. Because the Hybrid concept may involve any two or more different welding/brazing/joining processes, it is welcome to state clearly what processes are involved. Thus a more correct name could be Laser-GMA Hybrid Welding. For the sake of simplicity, everybody admits that LHW without any other specification addresses Laser-GMA Hybrid Welding. On the other hand, the name Hybrid Laser Welding can be found in many issues..." "...We find this denomination as inappropriate, because not laser, but the welding process is hybrid..." "...When approaching LHW, specialists have a look firstly at the advantages of arc welding: low cost energy source, gap bridgeability, microstructure that can be influenced etc. On the other hand, the advantages of using Laser Welding are also clear: increased penetration, high welding speed, low thermal influence, high mechanical performances at the joint. As a holistic approach, LHW is meant to bring low heat input, low deformation, better metallurgical quality, higher welding speed, low distortion, higher bridgeability and lower spattering, as too..." (quote Prof. Dr.-Ing. Danut Iordachesu - Conference Proceedings of the IIW Intermediate Meeting Commissions IV and XII, Vigo, Spain, 11-13th April 2007).
As you can see Henry, I guess here is a lot of future work to do before we all can use the correct acronym for Laser-Arc Hybrid Welding, I hope you may agree with me.
But nonetheless I am sure that all the people who are involved in either using the process as a great alternative to "conventional" welding processes or who are involved in Research and Development are on the right way for finding these terms in the future. From my very personal point of view, the first steps have been done already only by having seen that there is the necessity to create a common valid predefinition of terms, for at least helping the potential process-user to basically understand what he is talking about.
My best regards,
Stephan