Principles of action of nanoparticles with defined interfaces in cutting fluids
Initial situation and objective
The use of cutting fluids (CFs) is essential for many processes from a technological perspective. At the same time, economic and ecological disadvantages can be expected with the use of CFs. Conventional flood cooling lubrication (FCF) is particularly associated with the use and operation of energy- and cost-intensive peripheral elements such as pumps and filtration systems. A promising alternative to FCF is Minimum Quantity Lubrication (MQL). In this supply strategy, the CF circuit, and thus a large part of the CF peripherals, are dispensed with. However, the lack of cooling effect of MQL is a disadvantage, and in temperature-intensive processes (e.g., grinding processes), MQL cannot yet be effectively implemented.
The state of research shows that both cooling and lubrication properties of MQL base fluids can be significantly improved by adding nanoparticles (combined as "nanofluids"). To unlock the potential of MQL in grinding processes, nanofluids are qualified and used in the "Nano-KSS" project. The overarching objectives are to understand the underlying mechanisms and to design nanofluids specifically for MQL fluids in grinding processes.
The project "Nano-KSS" aims to develop and optimize high-performance nanofluid cutting fluids for grinding processes. The focus of the project is on investigating and understanding various aspects of properties of nanofluids and their influence on processes.
(1) The primary objective is to understand the influence of particulate properties in nanofluids on their lubricating and cooling characteristics. To achieve this goal, different particle-base fluid dispersions will be produced, systematically varying particle properties such as size and morphology to examine materials with different material properties (hardness, toughness, thermal conductivity).
(2) Another objective is to comprehend the impact of particle interactions and agglomerate formation on the stability, rheological properties, thermal conductivity, and lubrication of nanofluids. This will be achieved through targeted post-synthetic modification of nanoparticles using stabilizers to control their compatibility with the base fluid and their mutual interactions. This process will result in nanofluid variants with different particle structures and viscosities. Additionally, the interactions between nanoparticles and conventional cutting fluid additives will be investigated.
(3) A further focus is on deriving mechanical and interfacial-specific parameters for predicting optimal property relationships. This includes creating empirical models to better predict the behavior of nanofluids during grinding.
(4) Finally, the project aims to design nanofluid cutting fluids strategically using the developed models. These nanofluids will be verified through experimental grinding investigations and compared with conventional cutting fluids to evaluate their performance.
The overall goal of the project is to contribute to enhancing the quality and productivity of grinding processes through systematic research and optimization of nanofluid cutting fluids, thereby opening up new possibilities for the application of minimal quantity lubrication.