A case study on the observability of cutting fluid flow and the associated contact mechanics in scaled rough surfaces

In grinding processes, heat is generated by the contact of the grains with the workpiece. In order to reduce damages on the workpiece and the grinding tool, cutting fluids are necessary for most grinding processes. They have the tasks of cooling and lubricating the contact zone and to remove the chips from the contact area. Different types of cutting fluids perform differently regarding these tasks, which can be investigated on a laboratory scale. However, the results of those experiments are limited to certain workpieces and processes and information about the contact mechanics are not available. The experimental investigation of contact mechanics under cutting fluid influence is hardly possible. For this reason, this paper uses a measurement strategy that uses scaled topographies and has already been successfully applied to contact mechanics problems. With such a setup, it is intended that at an early stage in the development of cutting fluids, their characteristics in terms of contact mechanics can be determined very efficiently. To demonstrate this approach, two different cutting fluids were tested with the help of the associated test rig—a water miscible emulsion and a non-water miscible grinding oil. The two fluids showed fundamentally different characteristics regarding their hydrodynamic load bearing effect, their influence on the friction behavior of the contact and their fluid flow in the gap. The properties analyzed here correspond to the practical application of cutting fluids. The results underline the potential of the presented setup for an integration into the development process of cutting fluids.