Surface texturing for tribology enhancement and its application on drill tool for the sustainable machining of titanium alloy

Abstract

The present work investigates the effectiveness of micro textures in reducing the sliding friction at the contact surfaces and its application on drill tools for the sustainable machining of Ti-6Al-4V. Preliminary experimental results from the pin on disc tests substantiated the tribology enhancing phenomenon of micro textured surfaces, with a better performance in case of micro dimpled surfaces recording a friction coefficient of 0.42. Hence for the first time, an attempt has been made to create micro textures on both the flute and margin side of the drill tools with an objective to minimize the cutting forces by reducing the sliding friction at the tool-chip and tool-work piece interfaces. Micro textures in the form of dimples were created on the flute and margin side of drill tool using laser micromachining technique. Drilling experiments were performed on Ti-6Al-4V work material by drilling a through hole of 10 mm depth using non-textured, flute textured and margin textured tools. From the cutting forces recorded during machining, it was observed that even at the higher cutting speed of 60 m/min and feed 0.07 mm/rev, the margin textured tool performed better than all other tool types recording a net reduction of 10.68% in thrust force and 12.33% in torque compared to non-textured tools. The investigations on the chip morphology further revealed less clogging of chips in case of flute textured tool which is a clear indication of a reduction in the chip evacuation force. The experimental results from this research work proved micro texturing of drill tool to be a viable technique for minimizing the energy loss due to reduction in frictional forces at the cutting regime while machining Ti-6Al-4V.