Improvement of the milling process performance by using cutting fluids prepared with nano-silver and boric acid

Abstract

Today, it is aimed to produce high quality products and reduce energy consumption in metal cutting processes. For this purpose, it is necessary to use cutting fluids with high tribological performance in metal cutting processes. With the use of these fluids, the lubrication and cooling functions required in metal removal processes will be provided effectively. In addition, minimal and effective use of fluids will reduce processing costs and energy consumption. In this study, tribological performances of cutting fluids consisted of nano-silver and boric acid were investigated comprehensively in the milling process of AA7075-T6 material. First, colloidal suspensions were prepared in ethylene glycol medium using nano-silver as a cooling and surface film-forming agent and boric acid as a lubricating agent. Secondly, milling experiments were performed according to semi factorial design method. Surface roughness (Ra) and cutting forces were considered as performance criteria. Visual and elemental analyses of chips were performed via scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) spectroscopy. Tool wear and build-up-edge (BUE) formation was examined by optical microscope. According to the results, the cutting fluid prepared with nano-silver (nAg) and boric acid (BA) in a medium of ethylene glycol (EG) decreased surface roughness by 14.59% more than the nAg and EG mixture and by 5.27% more than the BA and EG mixture. In addition, cutting forces of EG + BA + nAg was observed 0.846% and 0.115% lower than the EG + nAg and EG + BA, respectively. In terms of tool wear and chip morphology, EG + BA + nAg cutting fluid showed better results than other cutting fluids.