Aachen researchers to showcase laser metalworking skills at EuroBLECH

04 Sep 2018

Fraunhofer ILT will promote time- cost- and materials-saving methods, including metal-plastic welding, at next month's Hanover expo.

At the forthcoming EuroBLECH sheet metalworking expo, running from October 23 to 26, 2018 in Hanover, scientists from Fraunhofer Institute for Laser Technology ILT will be presenting five “groundbreaking” developments on all major trends in contemporary sheet metal processing – from hybrid lightweight construction to multifunctional laser robots with an integrated digital twin.

There is a common denominator for all five processes, ILT’s announcement states “they stand for different approaches to agile, laser-based manufacturing, and balance flexibility and productivity. Such manufacturing processes are particularly in demand for hybrid lightweight construction and electromobility – two major trends in sheet metalworking”.

“Laser technology combined with digitalization is a predestined solution for economically producing constantly fluctuating and unpredictable lot sizes in volatile markets“, commented Dr. Dirk Petring, group leader for Macro Joining and Cutting at the ILT.

Robot and laser processing

The lighthouse project MultiPROmobil fits in with this need: The NRW-funded project will be launched in October 2018 and coordinated by Fraunhofer ILT. A robot and a multifunctional laser processing head will be designed to enable clever interaction and integrate cutting, welding and generating of structures additively.

They are to be supported by a digital twin as well as intelligent design and simulation software. With MultiPROmobil, the Fraunhofer experts and their industrial partners say they want to reduce commissioning time by 30 percent and unit costs and resource consumption by at least 20 percent.

“In a subsequent expansion phase, a production facility with several robots will be built, in which each individual robot masters all three production disciplines“, said Dr. Petring. “In this way, process chains for the production of sheet metal assemblies can be made very flexible and scalable, especially with regard to the gradual introduction of e-mobility.“ Currently, the project participants are working on further developing the combi-head so that it can be changed between cutting, welding and now additive manufacturing processes as needed and without changing the optics and nozzles.

Laser beats the punch

At EuroBLECH the Aachen scientists will also showcase flexible high-speed cutting of metal strips: With assistance from Fraunhofer ILT, carmaker Honda has replaced the previous punching process – of sheet metal of up to 1.8m x 4.0m and a thickness of 0.5 to 2.3mm – with a rapid laser cutting process, with a speed of up to 115m/min at its plant in Yorii, Japan.

Honda says it has achieved an output of 18,700 car body parts per day since introducing the laser blanking system in 2015. Dr. Petring commented, “At the fair in Hanover, we will be reporting on the next step towards a very fast cutting process for differentiated rolled strips with partially different properties; we are currently developing this process together with Bilstein in Hagen, Germany.”

Steel joined

The lightweight construction trend towards ultra high-strength steels is the focus of a project funded by the German Federation of Industrial Research Associations. Within the scope of FAAM (“standing for Further development, joining technology validation and technical design of welded joints with martensitic chromium steels”), Fraunhofer ILT and its partners are developing and testing laser welding processes on various components.

The demonstrator is a laser-designed bumper module, which the Aachen scientists will use to demonstrate how different high- and ultra-high-strength materials can be laser-welded in a hybrid construction.

The optimal spatial and temporal adjustment of the temperature field plays the main role in the latest research in the field of laser heat treatment. In Hanover, Fraunhofer ILT plans to show how, by adapting the beam profile with the aid of a freeform mirror, areas and zones can be selectively and locally processed in order to generate defined strength profiles. the Aachen scientists are working with significantly higher feed rates.

Laser-based metal-plastic welding

The fifth exhibit, a roof bow created as part of the BMBF project HyBriLight, received the “Future of Composites in Transportation 2018 Innovation Award“ in Chicago in June 2018 at a JEC event. An original part of a vehicle from the BMW 7 Series was used as a model: a hybrid component with a fiber-reinforced plastic cross member (previously pure CFRP) and metallic connecting elements to the car body.

As an alternative to bonding and riveting previously used, the Aachen scientists use a laser- based joining process that connects plastic and metal with positive locking and adhesion. Moreover, material costs were significantly reduced by using GFRP instead of the more expensive CFRP. The latter is now used only as a strength-enhancing insert on the long sides of the cross member.

The roof bow is finally trimmed with an innovative laser cutting process, which allows processing of the material sandwich made of GFRP and CFRP in a single step. Several advantages speak in favor of innovation: reduction of process times by 70 percent compared to conventional processes, halving of raw material costs and the integration of several process steps into one process.