Integral lightweight construction for gear wheels by means of laser beam melting

In the first work packages, it was already possible to ensure reliable processing of the case-hardening steel 16MnCr5. For this purpose, manufacturing parameters were developed and optimized with regard to the achievable component density and surface quality. The mechanical properties determined are all in the range of conventionally produced 16MnCr5 and indicate good material properties for gear production.

Additive manufacturing (AM) offers new freedom in design, as familiar limitations can be ignored. This freedom of form is implemented in the gear wheels through lightweight design optimization and functional integration.

On the one hand, the lightweight design optimization was carried out by means of software-supported optimization, such as topology optimization. On the other hand, methods of bionic optimization were used, which transfer solutions from nature into technical components. Both approaches were used to develop gearings that have the potential to reduce mass by up to 35 percent, although the optimization space is limited by the specified gear rim and hub.

Bionic optimization is a generally valid procedure which is not limited to the application purpose of the gear wheels. In addition, the project evaluates the potential of integrated cooling of the tooth flanks. For this purpose, cooling channels are integrated into the structure of the gearwheel, which can only be produced by additive manufacturing.

In the next step, the manufactured gears are tested at the Research Center for Gears and Transmission Engineering (FZG) at the Technical University of Munich for their load-bearing capacity, running behavior and susceptibility to seizure and compared with conventionally produced gear teeth. The aim is to obtain information on the usability of additive-manufactured 16MnCr5 and to derive design rules for the lightweight construction optimization of gears.

The project is funded for 30 months by the German Research Foundation (RE 1112/50) and will run until the end of 2020. The exact relationship in the heat post-treatment of additive-manufactured components made of case-hardening steel is being investigated in an AiF project.