We can divide precision cold extrusion into three main processes: forward extrusion, reverse extrusion, and lateral extrusion.
Forward extrusion: The material flows in the direction of the displacement of the punch, it is pressed into the die through the hole, the diameter of the rod/tube can be reduced, the billet (tubular) is extruded through the forward extrusion die, the force is A punch and mandrel acting as a pusher is applied, reducing the outer diameter as the tubular portion elongates.
Reverse extrusion: The material flows in the other direction of the punch displacement, and the billet enclosed in the die is forced to flow backwards from the annular area located between the die and punch.
Lateral extrusion: The material flows perpendicular to the displacement of the punch, and the material surrounded by the punch and die is forced to flow through radially placed holes.