Modeling process temperatures in NC form grinding considering single grains, grain wear and grain load depending on the cooling lubrication strategy

• Applicant: Professorin Dr.-Ing. Petra Wiederkehr
• Subject Area: Metal-Cutting and Abrasive Manufacturing Engineering
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 550638850

In grinding processes, friction, small chip cavities, ploughing effect and a large number of simultaneous grain engagements result in high process temperatures. These can cause thermal damages of the workpiece surface and the tool and can lead to changes in the microstructure of the material or residual stresses in the edge zone. Modeling process temperatures offers the possibility to modify process parameter values in advance to prevent, e.g., thermal damages. Often, the heat transfer coefficient is approximated iteratively by using numerical simulations and measured workpiece temperatures, which are determined by using thermocouples at a defined distance from the workpiece surface. In this project, a new approach for modeling process temperatures on a single-grain basis will be developed, which will enable time-efficient simulations of process temperatures. The influence of the cooling lubrication strategy as well as the wear progress of the tool will be taken into account. The single grain temperatures will be empirically measured by cutting the fiber of a two-color pyrometer in the NC form grinding process using cooling lubricant. The systematic relation between the single grain engagement and the single grain temperature will be investigated by means of different parameters such as the chip cross section, the rake angle or the flank angle. These investigations will be based on a grinding process simulation, which has been developed in a previous research project. For this purpose, single grains, whose temperature will be determined experimentally, will be analyzed with respect to their engagement situation and the cooling strategy for different wear conditions. The knowledge obtained will be used to develop a temperature model based on individual grains, which can calculate the process temperature at the workpiece surface taking into account the parameters mentioned. In order to be able to represent the influence of the coolant strategy implicitly, the influence of the nozzle configuration during coolant supply on the developing single grain temperature will be taken into account for the calibration of the model. The temperature model can be used to derive a more sustainable use of coolant for process planning, e.g., through a reduced pump capacity with a corresponding nozzle configuration.

• DFG Programme: Research Grants