NEWS
New process to increase underwater welding efficiency
The Laser Zentrum Hannover (LZH) is developing a laser-assisted metal flux-cored welding process for use underwater. Whether for wind farms, coastal
protection structures, or harbours: when technical constructions have to be welded underwater, divers usually do it by manual electrode welding. While this process is relatively simple and inexpensive, it has a major disadvantage in that the diver must frequently replace the burnt electrodes. This means the process has to be interrupted repeatedly, especially for longer welds. In the BMBF-funded LaMeer project, LZH
scientists are therefore now developing an alternative process together with its industry partner, AMT from Aachen. The new process, called laser-assisted metal flux-cored underwater welding, aims to make welding underwater easier and produce better weld seams.
In standard flux-cored welding, a wire
is taken from a wire reel and melted. This allows significantly longer weld seams to be produced, thus increasing deposition rates and production rates. With the help of laser radiation the LZH scientists now want to optimise flux-cored welding further as a more efficient underwater welding alternative. To this end, they want to develop and test a welding torch prototype with integrated laser optics. The laser beam will insert energy into the workpiece in a targeted manner to improve arc ignition and stability. The work is based on research into laser beam-arc hybrid welding in an atmosphere, which has shown that the targeted combination of laser beam and arc in a common process zone allows the arc to be guided precisely, resulting in higher process stability and geometric accuracy of the weld seam. In addition, higher welding speeds and the over-welding of existing weld seams are possible.
Bettering brass joining The LZH is also looking to improve the welding of brass in another project with LMB Automation from Iserlohn. Brass’ high electrical conductivity,
Laser-assisted metal flux-cored welding will increase underwater joining efficiency and quality
high corrosion resistance and attractive appearance make it suited to many applications, ranging from fittings, machinery and apparatus engineering,
Fraunhofer ILT inaugurates Hydrogen Lab at AKL’22
Fraunhofer ILT has opened a 300 square metre research laboratory dedicated to realising the cost-optimised series production of hydrogen fuel cells, helping unlock their technological/economic potential and accelerating their structured rollout in industry. The ‘Hydrogen Lab’ was officially opened in Aachen on 5 May at the International Laser Technology Congress AKL’22. It offers a wide range of laser-
based experimental facilities that cover the manufacturing steps for producing metallic bipolar plates used in hydrogen fuel cells. This includes technology for welding and cutting, as well as for structuring and coating, which can be used to improve the efficiency
6 LASER SYSTEMS EUROPE SUMMER 2022
and functionality of bipolar plates. Test rigs will also be available to evaluate laser-manufactured components in terms of both hydrogen tightness and efficiency. Having such a space
will encourage seamless interdisciplinary collaboration, giving public projects and industry collaborations a space to achieve synergy at the highest scientific and technological level. ‘In Germany, of course, there
are other well-known research institutes working on hydrogen, and we are in constant exchange with them,’ said Dr Alexander Olowinsky, head of the Micro Joining Group at Fraunhofer ILT. ‘We could also work with component manufacturers for fuel cells, as well as with partners who
want to produce manufacturing technology, such as scanners or tools for process monitoring, or with those who want to test beam sources.’
Innovation Award for Laser Technology presented at AKL’22 The 2022 Innovation Award for Laser Technology was won by Primes at AKL’22 for its ScanFieldMonitor, a laser scanner characterisation system. The development of the system, carried out by Primes’ head of R&D Stefan Wolf and his team, was prompted by many new applications in the field of additive manufacturing and e-mobility. The ScanFieldMonitor’s
measurement principle enables the measurement of laser beam
to power plants, vehicles and shipbuilding. However, welding
the copper alloy is challenging due to process instabilities. The alloyed zinc evaporates below the melting temperature of copper. For this reason, pore formation and a high hot cracking tendency of the seams can occur. Therefore, in
Spectroscopic measurement data and adaptable beam profiles will be combined to control and stabilise laser brass welding
the project LaserMessing, the LZH and its industry partner are developing a laser-based manufacturing system for the automated series production of brass components, such as fittings, bearings, valves, turbines or heat exchangers. The partners are combining laser-based deep welding using adaptable beam profiles, with cored wire processes, to produce a stable, automatable process that produces weld seams free of pores, weld spatters and underfill. Thermography and spectroscopy data will be used to monitor the process and develop a process control system. In doing so, energy can be directed into the workpieces to reduce vapour capillary fluctuations. The use of core and ring spots will provide additional process stabilisation. The subsequent laser cored wire process then smooths the seam surface of the previously created deep welds.
Bipolar plate functionalised with USP laser microstructuring
parameters during the movement of a scanned vector. The resulting laser scanner characterisation provides all geometrical and laser- related parameters relevant to remote applications. Additionally, beam position and movement of the laser scanner unit in its scanning field are determined in the same operation.
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