Punch and Counterpunch Design by the Die Expansion Method in Completely Closed Die Forging
Design equations based on die expansion are derived for selecting punch and counterpunch dimensions in completely closed die forging. The method imposes lower limits on the punch (counterpunch) – container radial clearance and forging height tolerance that may be specified.
M. Marcos and L. Sevilla
A.O. A. Ibhadode, "Punch and Counterpunch Design by the Die Expansion Method in Completely Closed Die Forging", Materials Science Forum, Vol. 526, pp. 175-180, 2006