Cold Backward Extrusion of Titanium Billet with Pulsating Lubricant Supply on Servo Press

Abstract

To prevent seizure in backward extrusion of holes for lightweight structural components, an extrusion method utilizing a punch having an internal channel for supplying liquid lubricant to the punch nose was applied to forming of pure titanium billet using a servo press. On the servo press, the punch was pushed into the billet in a manner combining pulsed and stepwise modes. The sufficient amount of the liquid lubricant was pulsating supplied to the cavity formed at the bottom of the hole. Appropriate punch ram motion and forming limit for preventing seizure are determined from the surface observation of the formed hole and the punch.