A sustainable cooling solution for machining: Internally cooled toolholder enhanced by nanorefrigerants and electrohydrodynamic effect

Abstract

Alternatives to cutting fluids have been extensively researched in machining. While they provide lubrication and cooling for tools, they pose health risks, cause environmental damage, and increase manufacturing costs. Considering that many researchers worldwide have been focusing their efforts on new applications for nanofluids, the objective is to evaluate the application of nanorefrigerants alongside the Electrohydrodynamic Effect (EHD) in a similar device to an internally cooled toolholder in order to reduce or eliminate cutting fluids. R141b/Al₂O₃ nanorefrigerants with three different concentrations were prepared and subsequently characterized. A heating chamber similar to a toolholder was developed to circulate nanofluids, apply the EHD effect, and evaluate its efficacy in reducing cutting tool temperature. The nanorefrigerants remained stable for up to 48 h; their viscosities increased by 44–64%, depending on concentration. The thermal conductivity of the nanorefrigerant with the lowest concentration increased by 44%. The EHD effect showed positive results in all analyzed conditions, with an increase in the heat transfer coefficient (h) of up to 19%. However, higher nanoparticle concentrations resulted in a smaller increase in the h values. Based on the heat transfer coefficient, the internal cooling system proved viable for reducing or eliminating cutting fluids. The combination of nanorefrigerants and EHD Effect can enhance the internal cooling method, extending tool life.