Abstract

In this study, the coating of fine wires using hydrodynamic pressure technique has been investigated theoretically and experimentally. One of the principal aims of the project is to establish the minimum possible coating thickness on fine wires which can be applied by means of hydrodynamic technique. Models based on steady, uniform and laminar flow of Newtonian as well as non-Newtonian fluid for polymer coating for the process of plasto-hydrodynamic wire coating in a stepped bore unit have been developed. The closed form analytical solution is established in cylindrical coordinate since the practical case is a mathematical axisymmetric problem. The comparison of theoretical results between Newtonian and non-Newtonian fluid, and Cartesian and cylindrical coordinate systems has been made. The experimental procedures and methods have been outlined, a melt chamber and a die unit have been designed and used, and investigations into a wide range of coating and drawing conditions have been carried out. The experimental work includes by the polymer of low density polyethylene (Escoren) coating on stainless steel wires with three diameters ranging from 0.1 - 0.4mm, varying the temperature of the polymer melt between 120 - 155°C, converting the different diameters of dies ranging from 0.2 - 0.5mm, and shifting the drawing speed between 0.08 - 1.31m/s. The experimental data have been processed and presented graphically. Some significant conclusions have been made.