Compensation of Shape and Dimensional Deviations Due to Thermo-Elastic Deformation During Dry Machining

• Applicant: Professor Dr.-Ing. Thomas Bergs
• Subject Area: Metal-Cutting and Abrasive Manufacturing Engineering
• Term: from 2019 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 426824785

In conjunction with the further development of cutting materials in manufacturing technology, it is now possible in many applications to completely dispense with cooling lubrication of the cutting tool or to use only minimum quantity lubrication. In this way, it is feasible to save costs for the provision, maintenance and disposal of various cooling lubricants.The elimination of cooling lubricants during dry machining, however, causes a change in the process heat generated and its distribution within the thermodynamic system, consisting of tool, workpiece, chips and the machine tool environment. The occurring heat flows cause a deformation of the workpiece and an undesired displacement of the machine components. This results directly in deviations in shape and dimension of the manufactured workpieces, which is why process design is much more complex than using conventional cooling lubrication. Due to the temporal and spatial complexity of the physical process involved, the deformations that occur cannot yet be compensated by simple analytical calculations or empirical knowledge.The overriding goal of the transfer project is therefore to implement the compensation of thermo-elastic deformations on the basis of a real application case for the first time and thus to transfer it into industrial practice. For this, it is necessary to extend already developed methods by the thermo-elastic displacement of the tool. Subsequently, strategies for the compensation of such misalignments and deformations can be derived, which enable dry hard turning of complex components with high demands on shape and dimensional accuracy.The multi-scale procedure developed in the DFG research project "Development of a model for the calculation and compensation of thermo-elastic shape and dimensional errors during dry machining" enables the heat flows in the equilibrium state of a turning process to be calculated on a mesoscopic scale by means of a chip formation simulation and to be transferred to a macroscopic component model for the calculation of heating and ultimately thermo-elastic deformation. In the basic research project of the SPP 1480, the suitability of this approach for the precise and time-efficient calculation of the thermo-elastic deformations of a workpiece could be proven. This calculation forms the basis for deriving a compensation strategy to avoid dimensional and shape errors.

• DFG Programme: Research Grants (Transfer Project)
• Application Partner: CEROBEAR GmbH