Roving process refers to the further drawing and thinning of the sliver through the drafting device, and the improvement of the straightening parallelism and separation of the fibers, so as to spin the roving suitable for the drafting of the spinning frame.
At present, the drafting ability of ring spinning frame is not up to the requirement of direct yarn formation with sliver, so the roving process is needed between drawing process and spinning process to undertake part of drafting in spinning process. Therefore, the roving process is the preparation process for spinning. Its tasks are:
(1) Drawing lengthens the sliver by 5-12 times and further straightens and parallels the fibers.
(2) Twisting has a low strength because of the small number of cross-section fibers and good parallelism of stretching, so it is necessary to add a certain twist to improve the strength of roving to avoid unexpected elongation during winding and unwinding, and to prepare for spinning drafting.
(3) The winding forming coils the twisted roving on the barrel tube to form a certain shape and size package for storage, handling and adapting to the feeding on the spinning frame.