In the drawing of spinning, the fiber material has been opened and carded in the previous process to make a continuous strip of semi-finished products, that is, sliver, also known as raw sliver, but it cannot be directly spun into spun yarn, because the raw sliver The quality and structural state is still far from the requirements of the final yarn, and the straightness and separation of the fibers are poor. For example, most of the fibers in the green sliver are still in a buckling or hooked state, and some small fiber bundles exist; while the combed sliver has better straightness of the fibers, but the evenness of the evenness is poor. If these slivers are directly spun through the roving, the quality of the finished yarn will inevitably be affected, so they must be processed by the drawing process first.

Purpose and Mission

Combine several slivers, so that the thickness of different slivers can be overlapped randomly, which will improve the uniformity of the medium and long segments of the sliver.

The drafting uses roller drafting to thin the feed sliver and improve the straightness, parallelism, and separation of the fibers in the sliver. This is an important prerequisite to ensure that the yarn strength and evenness of the sliver reach a certain standard.

Mixing The method of repeated merging further makes the fibers of various characters in the sliver fully mixed to ensure that the mixed composition and color of the sliver are uniform.

The sliver will be made into a uniform fiber sliver, which is regularly wound into an appropriate package for use in the subsequent process.

Since the uniform mixing of fibers in the fiber strip requires a certain multiple of merging, and the straightening and parallel effect of the fibers also requires repeated U-turn drafting, the number of merging in each pass of the drawing process is usually more than 6, and the number of technological passes All are more than two.

The process of drawing

The drawing frame consists of three parts: feeding, drafting and forming, and winding. The working process of the cotton-type drawing frame is as follows: the sliver drawn from the feeding can passes through the guide plate, the guide roller, and the guide column, and is transported forward side by side on the guide table and enters the drafting device. The drafted fiber web is initially collected by the bundler, and then output by the bundle roller enters the guide tube and then condenses into strips through the horn head. After being compressed by the compression roller, the fiber strips are regularly coiled by the coiler In the output can before the machine.