EXPERIMENTAL STUDY ON ENVIRONMENTALLY-FRIENDLY MICRO END-MILLING PROCESS OF TI-6AL-4V USING NANOFLUID MINIMUM QUANTITY LUBRICATION WITH CHILLY GAS

摘要

This research experimentally investigates the characteristics of micro end-milling process of titanium alloy using nanofluid minimum quantity lubrication (MQL) with chilly CO_2 gas. In the nanofluid MQL, hexagonal boron nitride (hBN) particles having a lamellar structure are used. They have high aspect ratio and enable sliding against other particles, which can provide better lubricity. In addition, the chilly CO_2 gas enhances a cooling effect during the micro end-milling process. A series of micro end-milling experiments are conducted in the meso-scale machine tool system, and milling force, coefficient of friction, surface roughness and tool wear are observed and analyzed according to varying lubrication and cooling conditions. The results show that the nanofluid MQL with chilly gas can be effective for reducing milling forces, coefficient of friction, tool wear and improving surface quality.