Development and validation of a generic temperature model for milling tools

• Applicant: Professor Dr.-Ing. Thomas Bergs
• Subject Area: Metal-Cutting and Abrasive Manufacturing Engineering
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 494849240

The main objective of the project is the construction and validation of a temperature model for industrially used milling tool geometries in the dry 3-axis machining process of steel grade C45E. For this purpose, a geometric engagement simulation including a force model based on a multi-scale approach is to be extended by a temperature model based on GREEN's functions. Input variables of the model will be, besides specific cutting force coefficients, specific heat flow partitions into the tool depending on the process parameters. These quantities will be determined by experimental orthogonal cuts and numerical, two-dimensional FEM cutting simulations. A partial goal is to build up a material database from the experimental and numerical experiments, whose input and output quantities are finally summarized in a model via regression. This regression model is then integrated into the overall model and is kept up-to-date with the database.The overall model, consisting of geometric engagement simulation, force model, temperature model and regression model for specific parameters, should thus be able to simulate not only the local, time-varying forces at the cutting edge but also time-varying temperature fields along the cutting edge and within the tool wedge. The main objective is to validate the time-varying force and temperature curves along the cutting edge in an experiment under real process conditions, but without the use of cooling lubricant. Milling tools with significantly different geometries (e.g. end mills, ball-end mills, different diameters, number of cutting edges) and process parameters will be investigated. The project puts forward the following working hypothesis: In the course of a multi-scale approach, it is possible to analytically predict time-varying temperature curves for industrially used milling tool geometries and process parameters by means of an engagement simulation and a coupled temperature model.The work program will consist of five work packages. In AP 1, an analytical-physical simulation model for parameterizable tools and arbitrary engagement conditions in the 3-axis milling process is to be built. Input variables into this model are specific thermal and mechanical parameters, which are inductively determined from empirical (AP 2) and numerical-virtual (AP 3) experiments. A database and a regression model (AP 4) are derived from these parameters in AP 4. The combination of the individual developments finally takes place in AP 5 within the framework of a deductive validation step for the real, dry milling process and the overall model.

• DFG Programme: Research Grants