Carded Slivers are fed into the Draw-Frame and are stretched/Straightened and made in to a single sliver. Also fibre blending can be done at this stage. The cans that contain the sliver are placed along the draw-frame feeder rack, usually including eight pairs of cylinders (each pair is above the space occupied by a can),the lower cylinder is commanded positively, while the upper one rests on the lower one in order to ensure movement of the relative sliver that runs between the two.
Tasks of the draw frame
- Dust removal
The reduction of weight / yard of sliver and increase in length is called drafting. Or Attenuation of sliver without breaking is called draft.
Break draft: Draft b/w the 2nd and 3rd rollers is called break draft.
Main draft: Draft b/w the 2nd and front rollers is called main draft.
1. Straightening of crimped and hooked fibers
2. Paralleling of fibers
3. To produce more uniform of sliver of definite wt/yd
4. To reduce wt/yd of materials fed
5. To make perfect blending/mixing of the component fibers
Waste of draw frame
1. Filter waste
2. Clearer waste
3. Sliver cut
Within the sequence of m/c in cotton spinning mill, the drawframe is the definitive compensation point for elimination errors. Inadequacies in the product leaving the drawframe not only pass into the yarn, they are actually reinforced by drafting effects following the draw frame. The yarn is never better than the draw frame sliver
At drawing stage, material passes not only one m/c but usually 2, arranged 1 after the other & combined to form a group. Processing in 2 passages is necessary completely to fulfill the requirements. The 2nd passage is often superfluous after combing m/c because then it does not normally generate any improvement in quality.
In old machinery 3 drawings were used, breaker, intermediate & finisher. But now in latest m/c only 2 drawings, breaker & finisher are used & in D-35 only one drawing is used.