Speaker
Description
In grinding processes, process parameters are currently set based on experience or empirical trial-and-error tests since little knowledge about basic interactions between process parameters exists, and contrary influences must be balanced. Especially when developing new cutting fluids, a conflict between cooling effects and hydrodynamic load-bearing effects arises. To resolve this conflict, a model should be developed to investigate these interactions and optimise wet grinding processes.
This model can be divided into two parts. A macroscopic description of a grinding wheel is firstly developed to model the pressure built-up, cavitation and thermal effects driven by viscous shearing. The numerical analysis on this scale is conducted via isogeometric analysis (IGA) based on NURBS. This approach, while mainly used for structural problems, is employed to efficiently compute hydrodynamic parameters, especially for problems with complex shaped geometries.
However, this modelling approach can hardly be used to capture the coefficient of friction arising from the engagement of the abrasive grains on a microscopic scale. To account for this influence, a microscopic model has been built based on a probability density function derived from measured deterministic height profiles. This approach, adapted from metal forming simulations, enables a comparably fast computation of the real contact area and an approximate penetration depth of the abrasive grains into the workpiece. By accounting for the influence of surface roughness and contact areas on the hydrodynamic pressure build-up on the microscopic scale, this model opens up the possibility of approximating a global coefficient of friction by linking from the microscopic scale back to the macroscopic scale.
This integrated modelling framework demonstrates how these considerations can be combined to create a lean modelling procedure for optimizing wet grinding processes through numerical analysis.
