Abstract

The real challenge pertaining to high aspect ratio drilling is the rapid increase in chip evacuation force due to chip clogging phenomenon occurring at higher drilling depths. The clogged chips will further impede the reachability of cutting fluid at the machining zone leading to the tool temperature buildup. This will eventually result in the catastrophic failure of the tool. Hence in the present work, an attempt has been made to minimize the chip evacuation force by functionalizing the drill tool surfaces based on the laser microtexturing principle. Microscale textures in the form of circular dimples were created on the flute and margin side of the drill tool with an objective to control the sliding friction, thereby minimizing the chip clogging effect. The effectiveness of the functionalized drill tools were assessed mainly based on the variation in thrust force and torque. Drilling experiments showed a net reduction of 17.18 % in thrust force and 26.98 % in torque while machining Ti-6Al-4V using flute and margin textured tool, which justified the effectiveness of micro scale textures in minimizing the chip evacuation forces. The outcomes from this research work will be highly beneficial for the manufacturing industries including aerospace, automobile and spacecraft as high aspect ratio drilling of titanium alloys are still categorized to be the most challenging machining process owing to its lower thermal conductive property.

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