FOCUS ON JOINING
Cold Metal Transfer ( CMT ) iWave Pro 400 AC / DC ready to weld with its two welding torches for TIG and MAG processes .
The Fronius CMT ( Cold Metal Transfer ) welding process is used when joining different materials , for example steel and aluminium . Extremely low heat input and an exceptionally stable arc set CMT apart from conventional MIG / MAG welding .
The digital process control detects a short circuit and then helps to detach the droplet by retracting the wire : during welding , the wire moves forward and is pulled back again as soon as the short circuit occurs . As a result , the arc only introduces any heat for a very brief period during the arcburning phase .
The short circuit is controlled and the current is kept low , resulting in spatterfree material transfer . The arc length is detected and adjusted mechanically . The arc remains stable , no matter the surface of the workpiece or how fast the user welds . CMT , says Fronius , can be used everywhere and in every position .
CMT welding is suitable for joining steel and aluminium , as the galvanised steel plate is wetted by this brazewelded joint while the aluminium melts . The process is also suited to the virtually spatter-free brazing of hot-galvanised and electrolytically galvanised sheets with a welding wire made from a copper-silicon alloy . Minimal distortion of the galvanised sheet occurs and the light-gauge welding of aluminium sheets ( from 0.3mm ) is also possible , whereby the low heat input eliminates the need for pool support .
“ When we need to weld identical parts with the highest weld quality , we turn to Fronius as it always has the solution ,” commented David Viñolas , Managing Director , Viñolas Metall .
One specific challenge for Viñolas is welding beams for swimming pool roofs from austenitic chrome-nickel steels 304 and 316 . The welding solution consists of a robotic welding cell equipped with a TPS 400i CMT welding machine , a hollow arm welding robot and an H reverser , which has two vertical turntables on a horizontal axis on both sides . Custom-made clamping devices are mounted between the turntables , each of which can accommodate four of the stainless-steel beams .
“ Once one side of the H reverser is loaded with four steel beams , they are turned into the welding cell and joined in a single cycle . Meanwhile , on the other side , the finished welded components are removed and four new ones are positioned , saving valuable cycle time . As soon as the system teaching is complete , the sequence program together with axial movements is specified and the weld quality ensured . Component handling can be carried out by trained operators who do not have to be experienced welding specialists , a particular benefit in times of skills shortages ,” explained Fronius .
“ We want our best welders to work on large projects with high added value , while smaller series parts can be welded with the robotic welding cell ,” added Viñolas Metall ’ s mechatronics engineer , Matheus Borborema . The Cold Metal Transfer ( CMT ) process used in the welding cell is characterised by its minimal heat input , which reduces the heataffected zone and therefore the deformation of the base material . At the same time , it offers high arc stability . CMT , explained Fronius , enables higher welding speeds with low spattering , minimising uneconomical rework and costs for consumables .
iWave Pro in robotic welding cells
Viñolas Metall has been placing its faith in Fronius since 2016 , when the first TPS / i welding system for intelligent MIG / MAG welding was introduced . Recently , the company has been facing a new challenge : the welding robot needed to weld various components using both the TIG and MIG / MAG process with rapid process changes and programmed configurations . Welding quality and system stability had to be kept constant throughout . The welding solution that Viñolas Metall chose to meet this challenge was the iWave Pro AC / DC multi-process welding machine from Fronius .
Viñolas Metall operations .
“ The reliability of the equipment and service quality of technology partners are key factors for us ,” emphasised David Viñolas . “ The Fronius support team fully supported us during the test phase of the new iWave Pro . We have now purchased four more devices .”
Viñolas plans to gradually replace all its old equipment , so that by 2025 all 15 welding cells will be equipped with the iWave Pro and all the company ’ s welding machines will be Fronius devices . Its main reason for purchasing the multi-process welding machines is the rapid process change .
28 | ismr . net | ISMR June 2024