Robot research cell with automatic processing head changing system during wire laser material deposition at Fraunhofer ILT. (Credit: Fraunhofer ILT, Aachen, Germany)
A collaborative research project funded by the German Federal Ministry for Education and Research (BMBF) aims to develop an efficient hybrid additive manufacturing cell for the production of large metal components.
The ProLMD project, which was first initiated in 2016, combines conventional production methods, laser material deposition (LMD) and robotics into a modular cell which can be easily integrated into existing process chains.
Engineers at Fraunhofer ILT are working alongside seven industry partners including MTU Aero Engines, Airbus and Mercedes-Benz on a number of application areas such as reinforcing, modifying and repairing existing parts. Airbus, for example, is exploring LMD for component reinforcement by 3D ribbing, while Mercedes-Benz is applying it for the adaptation of a press tool in body production.
In a report from Fraunhofer ILT, Jan Bremer, a scientist at the institute in Aachen, explained: "These examples show what we understand by hybrid manufacturing.
"It is the flexible combination of advantages from different manufacturing processes, as it combines any conventional manufacturing process with LMD to form a continuous process chain."
The process has been described as highly flexible and the partners are using both wire and metal powder as feedstock to open up further applications. Fraunhofer ILT has also developed a processing optic which generates a ring beam for coaxial laser material deposition with a uniform intensity distribution. Deposition rates in the range of 1 to 2 kg/h at high geometric resolution are being developed as part of the ProLMD project.
Additional partners include Laserline GmbH, M. Braun Inertgas-Systeme GmbH, BCT Steuerungs-und DV-Systeme GmbH, and the Lasertec business unit of KUKA, which is lending a multi-axis robot to allow components weighing up to 1.2 tons and with a diameter of two meters to be processed.
Bremer commented: "In the test facility, we can use up to eight axes to access a component of almost any complexity from all sides. The machine technology can be implemented at an amazingly low cost by means of robots."
Fraunhofer ILT's Aachen facility currently houses two cells including one large and one more compact version. With additional funding from BMBF, the researchers are aiming to create a cheaper version for SMEs scaled down from a 3.1m long robot arm with 90 kg load capacity to 2m with a 60 kg capacity. The larger version features a flexible changing system with wire and powder-based processing heads, while the small cell focuses on powder-based LMD.
