Experimental investigation of micro-pillar textured WC inserts during turning of Ti6Al4V under various cutting fluid strategies

Continuous shearing of the chip under the condition of seizure at the chip/tool interface has been recognized as a major source of heat input to the tool. This heat is unsafe for the tool life as it exhibits high plastic deformation of the sharp cutting edge under the action of high compressive stresses, leading to flank and crater wear. To diminish the severity of this condition, it seems impelling to decrease the chip/tool interface contact and enhance cutting fluid (air/liquid) penetration and retention into this seizure zone. Surface texturing of cutting tools has been gaining popularity in this aspect. This work extensively studies a turning operation using innovative textures fabricated using the Reverse Micro Electrical Discharge Machining (RμEDM) process on the tool surface. These textures, in the form of arrayed micro-pillars, were tested under dry, compressed air, MQL, and wet conditions during the turning of Ti6Al4V. The objective is to understand the ability of these micro-pillars to influence the cutting action in terms of tool wear, contact area, severity of adhesion, surface roughness of the work material, and chip morphology. It is visible from the overall experimental results that the textured pattern has the potential to decrease the chip/tool contact area by promoting tighter curling of the chips. A maximum of 52.3 % reduction in chip curl radius is achieved under compressed air condition. The textures assist in reducing the intensity of adhesion as high as 68.22 % on the chip/tool interface under dry machining and, hence, the temperature input to the tool. A similar deduction can be made from the reduced flank wear width with a maximum reduction of 18.45 % under wet conditions, indicating prolonged sharpness retention of the cutting edge. The measured feed forces also concur with the reduced contact area at the interface. A reduction of 30.96 % in the contact area is achieved, corresponding to a 19.73 % reduction in feed force under wet machining condition.