Effect of sustainable cooling and lubrication method on the hole quality and machinability performance in drilling of AA7075 alloy with cryogenically treated carbide drills

The present study examines the machinability performance of AA 7075 alloy under dry, air, and MQL-assisted machining conditions with cryogenically treated drills. The machinability performance of the AA 7075 alloy was evaluated in terms of surface roughness, cutting temperature, tool wear, deviation from diameter and circularity. Drilling tests were created using the Taguchi Taguchi L18 index. The cutting tool, cutting environments (dry, air and MQL), cutting speed, and feed rate were selected as drilling parameters. The data obtained from the drilling experiments were subjected to statistical analysis using the following techniques: signal-to-noise ratio (SNR), variance (ANOVA), and regression. The outcomes of this study show that cryogenic treatment increases the microhardness of tungsten carbide drills and positively affects machinability performance characteristics. It was also determined that surface roughness, cutting temperature, deviation from diameter and circularity values were approximately 99.81 %, 27 %, 38 %, and 40 % lower in air-assisted machining conditions and approximately 33.62 %, 30 %, 42 %, and 50 % lower in MQL-assisted machining conditions, respectively, compared to dry-machining condition. Moreover, SEM examination shows that the dominant wear mode for the cutting tools is built-up chipping (BUE) and negligible tool chipping occurs.