Investigation of MQL parameters in milling of titanium alloy

Rational parameters for the minimum quantity lubrication (MQL) are essential to reduce cutting temperature and extend tool life during titanium alloys’ milling processing. However, little research has been done on the effect of nozzle elevation angle on Ti-6Al-4V milling. This article’s objective is to experimentally elucidate the impact of various MQL parameters, including oil flow rate, nozzle distance, and nozzle elevation angle in the end-milling of Ti-6Al-4V. Response surface methodology (RSM) analyzes MQL parameters’ influence on the cutting temperature, milling force, and acceleration. Results demonstrated that cutting temperature first decreases and increases with the increase of the oil flow rate increased from 30 to 250 ml/h. When the nozzle distance is either too large or too small, the measured cutting temperature, cutting force, and acceleration are higher than those measured at a nozzle distance of 60 mm. The nozzle elevation angle is the predominant factor affecting the experimental results. And proper nozzle settings can reduce the cutting temperature by 15 °C, the cutting force by at least 5.6%, and the acceleration by 8.9%.