Wire drawing and coating using a combined geometry hydrodynamic unit: Theory and experiment

In conventional drawing, the diameter of the wire is reduced by pulling it through a reduction die. By plasto-hydrodynamic technique, the wire diameter can be reduced by a limited amount without using any conventional reduction die. In this process, the wire is pulled through a tubular orifice of certain bore which is filled with a viscous fluid (polymer). The smallest bore size of the orifice is always greater than the diameter of the undeformed wire and hence it is possible to avoid metal-to-metal contact. During the past few years, plasto-hydrodynamic wire drawing has been investigated by different researchers using either stepped parallel or tapered bore pressure unit. In this paper, wire drawing and coating using a combined parallel and tapered bore hydrodynamic unit has been modelled considering that the polymer is a non-Newtonian fluid and results are obtained for different wire speeds in terms of the changes in viscosity, shear stress, percentage reduction in area, pressure distribution and coating thickness.