Takashi Kuboki

Effect of Tension and Crash on Reduction in Wire Diameterduring Wire Drawing with Two Concave Rolls

In recent years, forming processes of ultrafine and precise products have been playing a key role in the enhancement of the performance and functions of machines and equipment. In particular, ultrathin wire is expected to be used as a material with versatile functions. Wire drawing using hole dies has conventionally been used in the manufacture of thin and ultrathin wires. In thin conventional drawing, dozens of dies with specified hole diameter corresponding to each target diameter of wires are needed. Moreover, in the recent trend of miniaturizing dimensions, the die itself would be difficult to manufacture. In this research, a new wire-drawing method without a die is proposed. The proposed method has a similar machine composition to two roll straighter, i.e. wire is deformed between two skewed rolls. A series of finite element analysis was carried out to examine the suitable roll profile and the effect of crash and tension on the reduction in wire diameter. On the basis of the analysis, a prototype machine was designed and used to verify the efficiency of the new method. Results showed that an 11% reduction in diameter was achieved under optimum condition.