Tool performance in high speed finish milling of Ti6AI4V

High feed rates may be achieved when finish milling titanium (Ti6AI4V) alloy (300HB) at speeds of 152-305 rrgmin (500-1000sfm). Three tool materials (micro-grain C2 carbide, fine-grained C2 carbide, and a TiA1N coated carbide) were tested using liquid (flood and through-spindle coolant (TSC) at pressures of 2.07 MPa), pressurized air (69-689 kPa (10-100psi)), and dry (no coolant) coolant conditions to prolong tool life. Tool wear manifested itself in two distinct patterns, gradual flank wear or micro-chipping leading to gross fracture. Which of these will lead to tool failure, will depend largely on the ability of the coolant to cool the tool (retard flank wear) without inducing thermal shock. Typically, under pressurized air, speeds up to 267 ngmin (875sfm) and chip loads of 0.057-0.114 mm (0.00225-0.0045") may be attained. Copyright © 2002 by ASME.