Ring Rail Movement and Builder Motion
topic
The ring rail carries all rings on a frame and moves up and down (traverse) to distribute yarn across the cop. Traverse speed ratio (upward/downward stroke speed) is typically 1:1.5, with the downward stroke faster to lay yarn at the correct angle. Builder motion (cam or electronic) progressively shortens the stroke length as the cop builds to maintain correct layer angle as the bobbin diameter increases from 25 mm (empty) to 45–55 mm (full cop).
Role
Ring rail motion directly determines cop building quality, which in turn controls autoconer efficiency in subsequent winding. A correctly programmed builder motion reduces unwinding breaks at the winder by 20–40% compared to incorrectly set traverse, directly improving overall mill productivity and reducing splice contamination in the finished yarn.