Project Details
Projekt
Simulation and optimization of the coolant flow to reduce the thermal tool load during discontinuous drilling of Inconel 718
Subject Area
Metal-Cutting and Abrasive Manufacturing Engineering
Term
since 2020
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 439920593
When designing industrial manufacturing processes, production engineering is increasingly faced with the challenge of meeting the demand for resource efficiency. The drilling of special alloys that are difficult to machine is characterised by high thermomechanical tool loads, which motivates research into potential optimisation approaches for the wear-reduced use of cemented carbide. In this context, a discontinuous process control was established for the drilling of Inconel 718, which enables cutting fluid flushing of the highly loaded cutting edges as a result of implemented retraction movements contrary to the feed direction. The resulting rewetting of the cutting edges enables heat transfer into the fluid and reduced thermal loads. The efficient introduction of this interruption of cut is the overarching objective of the bilateral research project. The development of a comprehensive simulation model that maps the bidirectional heat transfer, taking into account chip formation and coolant flow, should enable the prediction of cutting edge temperatures and provide a threshold for exceeding thermal load limits. This means that interruptions of cut can be introduced efficiently and the required tool cooling can be brought about as needed. As part of the first two funding phases, a database was generated by experimental reference studies on discontinuous drilling, which was used for the separate development of a flow simulation and a chip formation simulation. The respective simulation results were validated by means of flow visualisation and the recording of thermomechanical tool loads. Based on this, a coupled simulation model was realised which, in line with the objective, is capable of functioning for the simulation-supported process design of discontinuous drilling. To further develop the simulation model, material and friction modelling was carried out to further increase the quality of the data transferred to the CFD simulation. On the other hand, the simulation of the drilling process benefits from increases in complexity in the CFD simulation environment. The third funding phase focuses on the simulative investigation of the effect of increased cutting values on the thermal tool load in order to design an increase in productivity of the discontinuous drilling process in conjunction with the optimised definition of the cutting interruption. Furthermore, the special alloy Ti6Al4V is implemented in the coupled simulation model and the use of water-based cutting fluids is analysed. The simulation model is also used to develop flow-optimised tools. In conclusion, the combined findings will be used for recommendations for industrial applications.
DFG Programme
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