In grinding processes, process parameters are currently set based on experience or empirical trial-and-error tests, as little knowledge exists about the basic interactions between process parameters, and balancing contrary influences is necessary. To analyse and resolve conflicts of objectives, a model is developed to investigate these interactions and to optimise wet grinding processes. The model can be divided into two parts. On a macroscopic level, the Reynolds equation is used to model the hydrodynamic pressure build-up, while a newly developed cavitation algorithm based on the shifted penalty method is utilised. Additionally, the influence of the grinding wheel’s porous structure on the pressure distribution is examined by coupling the consideration of the porous domain to the Reynolds equation. Numerical analysis at this scale is conducted via isogeometric analysis (IGA) based on NURBS. This approach efficiently computes hydrodynamic parameters and enables coupling with a thermal consideration of the fluid while maintaining a reasonable system size for a monolithic approach. The second part of the process modelling is the consideration of the engagement of the grinding grains. To account for the contact forces of the cutting mechanism, a microscopic model has been built based on a probability density function derived from measured deterministic height profiles. This approach enables a comparably fast computation of the penetration depth of the abrasive grains into the workpiece and the resulting forces. By accounting for the influence of surface roughness and contact areas on the hydrodynamic pressure build-up at a 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 considerations of different sub-processes can be combined to create a lean modelling procedure for optimising wet grinding processes through numerical analysis.