NEW TECHNIQUE IN ROTARY FORGING.

A new technique is described in which three dies act radially on a cylindrical billet. An eccentric on each die produces a small circular motion at the point of contact which reduces the diameter of the workpiece and rotates it incrementally. The dies may also be fed radially inwards and parts whose shape is a solid of revolution can be produced. The system permits a reduction in noise and overall forces on the machine and, because dies can be used which conform closely to the billet surface, good penetration of the zone of plastic deformation can be achieved. This technique is similar to the Marciniak spline forging system but because of the feed capability of the dies, parts of non-uniform cross-section can be produced and also the use of three dies rather than two reduces the possibility of producing internal defects in the billet.