Experimental and theoretical examination and development of methods to calculate required pull force in wire drawing

Wire drawing is one of the oldest and most common cold metal forming processes. Wire is drawn through a single die or a set of conical dies to make it longer and stronger. In the drawing die there are three geometrical parameters that affect the drawing force: die diameter, die angle and bearing length. The force required to pull the wire through the drawing die has been investigated numerous times over the years and new drawing force equations have been developed. However, some of today's most widely used equations do not include the influence of the bearing length. In this paper the most common methods to calculate the drawing force are evaluated by means of wire drawing experiments and finite element studies. From the results, a novel equation for calculating the drawing force is proposed. The proposed equation is dependent on the bearing length and was compared with experiments and validated using finite element simulations with promising results.