Performance evaluation of tool coatings and nanofluid MQL on the micro-machinability of Ti-6Al-4V

Abstract

Micromilling of difficult-to-machine materials like Ti-6Al-4V alloy suffers from drawbacks such as tool wear and catastrophic tool breakage due to the tiny diameter of the micro tool. Hence, in this paper, an effort has been made to prolong tool life and improve surface quality via hybridization of water and CuO nanofluid-based MQL with PVD coated (AlTiN/TiAlN) and uncoated WC micro end-mill in micromilling of Ti-6Al-4V alloy. The results exhibited minimum surface roughness at lower concentration (0.25 vol%) of CuO nanofluids with AlTiN coated WC tool and diminished tool wear and built-up edge formation at higher concentration (1 vol%) water-based CuO nanofluids. Under various environmental conditions, the average size of the top burr width was determined on both the up and down milling sides. The minimum average burr width of 9.93 μm was obtained in up milling using 0.25 vol% CuO nanofluids condition with AlTiN coated tool. In the case of down milling, the minimum burr width was 10.58 μm when using 0.25 vol% CuO nanofluids with TiAlN coated tool. Furthermore, significant improvements in tool life and surface quality have been observed through the hybridized sustainable environments obtained by the combined utilization of MQL and coated tools.