Improvement of Straightner in Tension Annealing and Rotational Blade Straightner for Superfine Wire

Abstract

Higher straightness of superfine wires of 0.1 mm or less in diameter is in demand for recent development of electronic devices.
A rotational blade straightener is effective for straightening superfine wires. It is particularly effective for straightening coiled wires because the straightener can bend wires along the longitudinal and circumferential directions. We found that a higher rotational speed of blades, lower feeding velocity, and gradual decrease in curvature ratio during straightening were very effective in producing excellent straightness in rotational blade straightening.
Tension annealing is also one of the popular methods to straighten superfine wires. The tension annealing has a higher level of straightening effect without surface damage. The phosphor bronze and the tungsten superfine wires are used in this study. We observe that the initial radius of curvature, roundness and work hardening exponent are very important factors to make excellent straightness in tension annealing.