Surface texturing of Tribological Interfaces –An Experimental Analysis

Abstract

Abstract Surface texturing principle has already been reported to be successful in enhancing the tribological characteristics of various mechanical components including bearings, mechanical seal, piston rings, cylinder liner, etc. The current research work investigates the application of surface texturing principle on drill tools while machining titanium alloy. One of the major challenges pertaining to drilling of Ti-6Al-4V is the accumulation of heat at the machining zone due to the poor thermal conductivity property of the material. This factor deteriorates its applicability in various fields including aerospace, automobile, spacecraft, bio medical, etc. Accumulation of heat over the cutting regime will lead to rapid tool wear affecting the tool life and machined surface quality, which will eventually increase the total production cost. In drilling as the machining phenomenon occurs inside the hole, dissipation of accumulated heat is a real challenge. Moreover, the reachability of cutting fluids will get obstructed by the upward motion of chips along the helical groove. The above-mentioned challenge can be addressed by creating micro scale textures on drill tool surfaces, thereby controlling the heat generation by minimizing the sliding friction. Hence in the present work, micro scale textures in the form of circular dimples were created on the drill tool, and the same was coated for increasing the wear strength. Drilling experiments were performed under dry, wet and MQL conditions for evaluating the effectiveness of micro textured tools in cutting force reduction. From the experimental results, a net thrust force reduction of 13.83% in dry, 22.85% in wet and 21.65% in MQL condition were achieved while machining Ti-6Al-4V using coated flute and margin textured tool. Reduction in chip clogging phenomenon and lubrication enhancement provided by the coated micro scale textures are observed to be the underlying mechanism responsible for the lower cutting forces under all machining conditions.