Project area A

A01: Deformations of cutting tool and clamping devices and workpiece fixture devices and of the impact on cutting edge and workpiece deflections targeting on their optimization and compensation

The TP A01 focuses on solution strategies for the compensation and correction of radial and axial thermal tool errors under consideration of the influence of different cooling strategies. The models developed in phase 2 will be extended to identify thermal characteristics. With these results and a tactile temperature sensor system, a real-time capable correction method is developed and tested on real machining processes. In addition, the change in position of the workpiece due to thermal deformation of the fixture will be investigated.

A02: Model and method for the determination and distribution of converted energies in milling processes

The specific cutting forces generated in the process and the distribution of the resulting heat loss are influenced in many cases today by the use of cooling lubricants. This usually also has a reducing effect on the wear rate. In the 3rd phase of the subproject, the developed energy model and methods for recording and balancing the energy conversion in the milling process are to be extended by the influence of cooling lubricant and tool wear. The aim is to predict the temperature fields in the tool and the heat flow distribution in the process. For this purpose, the influence of cooling lubricant on the heat flow distribution in the cutting zone is fundamentally investigated and modelled. Initially, analogy tests in the form of interrupted turning tests are planned in order to validate the findings and models gained on a real, cooled milling process.

A03: Model and method for the determination and distribution of converted energies in grinding processes

The result of the 1st and 2nd phase is a parameterized process model providing a quantitative description of the heat fluxes into the components involved in the grinding process – tool, workpiece, cooling lubricant and chips. The influence of tool wear and cooling lubricant supply on the heat fluxes was not taken into account yet. As a result, the model becomes inaccurate as tool wear increases and the coolant supply changes. The objective of the 3rd phase is therefore to investigate the influence of tool wear and coolant supply on the heat flux in grinding and to extend the process model by these influencing variables.

A04: Thermo-energetic description of fluid power systems

Fluidic systems interact functionally and spatially with a multitude of machine tool components. Against this background, the knowledge gained on the individual test benches is transferred to a complete machine in the 3rd phase. At component level, design optimizations of fluid channels are transferred to a real motor spindle. On this basis, a control strategy for demand-oriented, energy-efficient heat dissipation is developed, taking into account the special features of the overall machine. At system level, the operating and control concepts developed are transferred to real machine operation. Particular attention is paid e. g. to determination of time constants and controller parameterization for a real process. This allows to quantify the potential of the optimized demand-oriented cooling systems including spindle cooling in comparison to conventional cooling.

A05: In-process system simulation of machine tool models

A05 focusses on the development, validation and provision of modelling technologies for the thermo-elastic simulation of machine tool models, which contain the methods and models developed by other subprojects of the CRC96 and can be used for various operational scenarios like the machine design or the structure model based correction of thermal errors at machine tool operation. The main goal of phase 3 is the provision of thermo-elastic machine tool models for given application scenarios, assembled from submodels of different types. Central areas of focus are the enhancement of the modelling technologies to determine the displacement field from the calculated temperature distribution as well as the estimation and assurance of the quality of the separate submodels. The range of validity, sensitivity and uncertainties of submodels and parameters are in paramount.

A06: Model order reduction

The simulation of high-dimensional machine tool models, as well as their integration into hardware controllers in thermal real time requires model reduction techniques. The main focus is to develop model order reduction methods for (potentially nonlinearly coupled) network models of entire machine tools (in cooperation with A05 and A07) with respect to given accuracy demands. Furthermore, the application of cooling lubricant gives rise to models with uncertainties. That is, specially tailored model order reduction methods need be developed and adapted to these new model properties. An other important working package is the parametric model order reduction for the use in parameter identification and uncertainty quantification (with e.g., B08). Finally, the consideration of nonlinearities, like e.g. hysteresis effects in C02, requires specially tailored reduction methods for nonlinear models.

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