African Fusion August 2018

Fronius’ second generation CMT

Automotive success for second generation CMT process Fronius’ secondgenerationTPS/i ‘coldarc’ CMTwelding system offers unprecedented levels of quality, simplicity and process reliability. Steel manufacturer and automotive industry supplier, voestalpine, was the first company to choose this advanced CMT technology for use in series production.

“ T he second generation of the CMT process represents another quantum leap in comparison to the previous version,” saysMichael Nowasz, headof the joining department at voestalpine Automotive Components. “We have noticeably improved our quality thanks to the numerous innovations and further developments of the TPS/i in combi- nation with the tailored CMT process and significantly extended our room for manoeuvre with regards to joining processes.” Through further improved dynamic process control, the new CMT (cold metal transfer) systemoffers lower heat input and even higher gap-bridging ability. “This is where Fronius’ chosen approach differs noticeably from other

processes, as droplet detachment and droplet transfer are not only controlled electronically by the power source, but are also aided mechanically via the wirefeeder,” says Nowasz. The wire electrode tip is retracted with the aid of apush-pull welding torch creating an ex- ceptionally stable arc that is effectively spatter-free. This additional stability also enables higher welding speeds. Reflecting on the introduction of the first generation CMT process in 2011 at the site inSchmölln, Nowasz says: “Since the switch, hardly any spatter has had to be removed, meaning my employees have been able to focus on what our customers fromthe automotive industry rely on: the quality of the weld seam.” A further benefit of the CMT solution from Fronius is the high availability of

Michael Nowasz, head of the joining at the voestalpine site in Schmölln, shows the results of Fronius’ second generation TPS/i CMT process. which voestalpine uses to manufacture various automotive structural compo- nents from galvanised, high-strength steel and aluminium sheets. Six of the twelve robotic welding cells at the Schmölln site currently use the CMT process. Those in charge at voestalpine reacted extremely positively to the second generation of the CMT tech- nology introduced at the start of 2016 and Fronius’ suggestion of testing its use in series production. “We selected an A-pillar made from high-strength galvanised steel for the initial welding trials. This complex component is not only ideally suited to putting the new process through its paces, but it also presents limited accessibility and large gap widths,” Nowasz explains. In the summer of 2016, the firstweld- ing trials with the new CMT process and the TPS/i took place in Fronius’ Institute of Technology at its headquarters in Wels. “I visited the laboratory with our head of development and experienced the newCMT process in action. What we saw there was simply fantastic. It was immediately clear to us that Fronius had made another huge leap forward,” he recalls. A completely redesigned TPS/i power source is at the heart of this progress. Fronius has redeveloped all the components: the controller, the communication bus and thewirefeeder- to-user interface, the cooling system and the hosepack. This has allowed the company to use the latest technology to prime the whole system for maximum precision.

the CMT system, he con- tinues. “If the arc is extin- guished for any reason, the process reignites it auto- matically. Ignition errors, the wire electrode welding to the contact tip or other similar annoyances are now a thing of the past for us.” The joining specialist also values the variety of options for influencing the welding process offered by Fronius aswell as the arc ge- ometry. This also includes the option of combining CMTwith a pulse process to better control a higher heat input into the basematerial via the arc, allowing faster welding. Due to the thorough- ly positive experiences, Nowasz ensured that the CMT process was added to the requirements specifica- tion for new welding sys- tems as a standard process for the arc welding of steel sheets of up to 3.0 mm,

At its Schmölln site in Thuringia, voestalpine Automotive Components produces ready-to-install stamped and formed parts, as well as complex assemblies and safety/impact protection components.

24

August 2018

AFRICAN FUSION