Optimized wobble milling to increase process efficiency and machining quality when machining CFRP

• Applicant: Professor Dr.-Ing. Volker Schulze
• Subject Area: Metal-Cutting and Abrasive Manufacturing Engineering
• Term: from 2019 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 413574937

The objective of this project is to optimize the existing wobble milling process to increase process efficiency and improve the machining quality in cooperation with an industrial partner. In addition to wobble milling further insights for tool design for machining fiber reinforced plastics (FRP) will be generated in this project. The subgoals of this project are to reach an increase of process efficiency and a reduction of damage with the optimized wobble milling process when drilling FRP, to develop a simulation program for process design and determination of tool geometry for multiaxial machining processes considering the material setup as well as to create a procedure for industrial process design. The optimized wobble milling should allow significant increase in efficiency in comparison to the present wobble milling caused by the new setup at additionally improved machining quality. The increase of efficiency will be ensured with the reduction from three to two process steps. In this way the process complexity as well as processing time for wobble milling decreases. The primary challenges for process development consist in the design and determination of interactions between the individual geometry parameters of the tool. The geometrical elements need to be balanced in a way that when machining the top layer in the first process step the process force needs to be directed downwards to the inner of the workpiece. In the second process step the process force at the bottom side needs to be directed upwards to the inner of the workpiece. The investigations of different layer structures with continuous fiber reinforcement ensure the spread of effective usability of the developed process. The challenge for the development of the simulation program consists in the description of the process kinematic, the implementation of material parameters and the developed process force models. With this program a new module will be created at which the process design can be adjusted to various requirements. The simulation is necessary for tool and process design and allows a dissemination of the developed processes to the industrial environment. Within the planed project a significant gaining knowledge for machining of FRP can be reached. In addition to the validation of the process an approach for the use of the optimized wobble milling in industrial environment will be developed. Therefore this research project provides a substantial contribution for a sustainable and economic production and offers a direct benefit for technical applications.

• DFG Programme: Research Grants (Transfer Project)
• Application Partner: GraGus CNC-Technik; Daniel Graef und Mario Gusenko GbR; Gühring KG
• Co-Investigator: Professor Dr.-Ing. Frederik Zanger