Slip, Wiredrawing

In wiredrawing machines, slip is the difference between the speed the capstan turns and the speed the wire is fed into the next die. When the capstan speed exceeds the wire speed, it is known as positive slip, which is required in certain machine designs. When the wire speed exceeds the capstan speed, the computed slip is negative. When the wire speed matches the capstan speed, the computed slip is zero. In a machine designed for zero slip, dancers are used after each capstan to control each capstan’s speed. When the computed slip is negative, the capstan does not pull the wire and the next capstan draws the wire through two dies, an undesirable condition that may cause a tension break the wire.