Wire straighteners usually consist of:
In this article we will deal with straightening and cutting.
Wire straightening is a process that goes back to the essence of steel production. Brief introduction to the problem: when cooling steel, various crystals and various defects at their borders are formed. During wire forming and production, the crystals are deformed and stress and defects remain at their boundaries. Therefore, the wire has a so called shape memory and different physical - mechanical properties in its length. If we want to transform this wire into a straight shape, we must disrupt the irregularities and stresses in the wire. Forming must take place beyond the limit of elastic deformations in the area of plasticity.
Forming can be achieved by a pulley method or a rotary method.
The most common way of forming is between a set of pulleys. The size, number of pulleys, their spacing, degree of transformation and speed of forming depend on:
Forming is carried out in at least two planes. In this way, we do not always have to achieve the required quality of straightness.
If we require the wire to be "absolutely" straight, it is necessary that the straightening takes place by the rotary method. (video link). The wire is transformed similarly as with a pulley straightener, just imagine that it all revolves around the axis of the straightened wire. There are also dependencies between:
and straightening turbine setting parameters such as:
For the owner of a wire straightener, it is ideal if these parameters can be adjusted. This increases the variability in the use of the wire straightener.
The straightened wire is transported to the dividing device. When cutting, the wire can stop in the straightening turbine, which either stops or rotates and continues smoothly in the straightening turbine.
This can be a problem, even if the wire stops in the rotating turbine only for a short moment. A visible trace is formed at the point of rotation, and at the point of twisting (with excessive cold mechanical deformation) the wire strengthens (stiffens) and may break. Sometimes this happens during later processing of the wire.
The ideal way to straighten a wire is if the forming takes place at a constant speed, at the same deformation angle, homogeneously throughout the whole volume of the wire. Flying shears or compensating wool must be used for cutting.
The way the wire is divided directly affects the quality of the cut. The best results are obtained if the die is only slightly larger than the diameter of the wire and the punch is shaped according to the wire diameter. We get a vertical and undeformed cut.