Experimental and model-based basic investigations on contact mechanical load distribution and the resulting production quality for wet grinding

• Applicants: Professor Dr.-Ing. Christoph Herrmann; Professor Dr.-Ing. Michael Müller
• Subject Area: Metal-Cutting and Abrasive Manufacturing Engineering
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 498570013

The grinding of metals typically generates high amounts of heat which must be transported out of the contact zone by a cutting fluid to avoid excessive workpiece temperatures and subsequently workpiece damages. In addition to cooling, the main tasks of the cutting fluid include lubricating the contact zone and removing the chips. The fulfilment of these functions is strongly dependent on the properties of the coolant lubricant and the type of its feed. An understanding of these process-structure-property relationships is of particular interest regarding the quality of the grinding process and a resource efficient use of cutting fluids. An assessment of the use of coolant lubricants with regard to the functions is usually carried out experimentally and only rarely or limited to models or simulations. In a first step, usually various test methods such as the Reichert-Test are used at the laboratory scale for the experimental investigation of the lubricating effect of fluids. However, these investigations only correspond to the real grinding conditions to a very limited extent and must therefore be supplemented by complex investigations at machine level. The existing numerical methods for the description of grinding processes usually consider either the single grit cutting during grinding or the hydrodynamics caused by the cutting fluid supply, a consideration of both factors is not known. Based on the identified research gap, the current project will investigate the influence of cooling lubricants on wet grinding processes. In interdisciplinary cooperation between production technology and simulation tools, the mechanisms which determine the close interactions of surface contours, hydrodynamics, force transmission, workpiece and tool topographies, material removal, heat generation and heat transfer will be investigated. Special attention is paid to the gap topographies, which change dynamically with the grinding process. The basis of the modelling strategy used here is a mathematical model based on the Reynolds equation, which is very flexible to possible extensions. Within the scope of the project, a close connection between experiments with innovative test equipment and models on different scales will be ensured. On the one hand, the studies on a modified Reichert-Test in combination with a model on the roughness level will be combined to characterize the processes on the microscopic scale. On the other hand, the hydrodynamic influence will be investigated both experimentally and by modelling. Finally, the knowledge is transferred to the machine level. The project represents a first essential step towards a holistic understanding of the influence of cutting fluids on the effectiveness of the wet grinding process. The models developed in this project will build the basis for further studies that will allow the implementation of optimization strategies for cutting fluids in the future.

• DFG Programme: Research Grants