UK: Silvergate/ColorMatrix — plastics colorants

Abstract

Wire drawing is an important industrial process. Wires are reduced in diameter through a series of die/capstan combinations which provide the desired reduction steps. Typical wire drawing machines within BICC Cables Ltd use up to twenty-one dies in one line and it is necessary to optimise the die drafting for each machine and final wire diameter to obtain good machine efficiency and high quality product. An important aspect in the manufacturing process is to avoid wire breakages with the resultant loss of production due to short final lengths and the associated time required to restring the drawing machine. In order to optimise the conditions for each machine and wire size, computer simulations of the process are used to predict performance by estimating factors such as the ratio of drawing stress to ultimate tensile stress, drawing force, back tension and heat generated.A computer simulation of the multi-line wire drawing process for copper wire has been modelled by the Wrexham Technology Centre of BICC Cables Ltd using a bulk model. The redundant work during the drawing process was included by formulation and equations for the redundant deformation were derived that were in good agreement with published experimental work.A new computer simulation has been developed to predict the performance of wire drawing process. The model uses a one dimensional explicit finite difference method to determine the plastic deformation in the dies. The redundant work formulation was used as in the previous simulation. This paper describes the numerical methods used and compared the results from the new computer simulation with the previous bulk model. Significant differences are predicted in the stress ratios, drawing force and heat generated for process predictions. The new simulation of the plastic deformation in the dies also indicated optimum semi-die angles away from the traditional eight degrees.