Cotton spinning system and process

Cotton ginning is the process of separating cotton seed from the lint so that the lint will be baled and goes to textile industries for further processing whereas the cotton seed is milled by oil mills to produce edible oil. It’s the first step of cotton spinning process.

An opening machine for separating the fibres from intermingled impurities in cotton tufts.

Opening machine comprise a supply cotton plate onto which the cotton tufts to be processed are introduced. At the bottom of the plate there is a licker-in which cooperates with cleaning blades to split up the fluffy masses of cotton at least partially into their individual constituent fibres. Therefrom, eliminating the intermingled vegetable impurities (parts of leaves, of capsules, of seeds, earth, etc.). In the vicinity of the licker-in there are usually suction openings for removing the impurities separated from the fibres and a duct through which the impurity-free fibres are removed.

In the Carding machine, the fibrous material is worked into a belt of untwisted fibres in the form of a web that will be condensed into carding sliver and passed on to subsequence processing stages.

The purpose of the carding operation is to turn raw material consisting of tufts of fibres, which have already undergone certain initial cleaning and opening processes, into a belt of untwisted fibres in the form of a web that is, as far as possible, free of impurities and non-homogeneities such as residual dirt from the previous process, waste and tangles or “neps”.

Drawing frames are mainly used to produce a fiber fleece that is as uniform as possible from a multiple number of fiber slivers. For this purpose, the stretch has one or more stretching units, which in turn comprise series of drawing elements, typically in the form of several successively arranged pairs of rollers, whereas the fiber slivers are guided between the respective pairs of rollers by clamping. Since the pairs of rollers feature peripheral speeds that vary and increase in the running direction of the sliver, the fiber slivers are finally stretched and thereby made uniform.

In a roving frame, also called roving machine or fly frame, a roving is produced from a sliver. The sliver is produced upstream of the yarn production process in a draw frame. The roving is the starting product for produce a yarn e.g. in a ring spinning machine. Thus, the roving is significantly thicker than a yarn but also significantly thinner than a sliver.

The main task of roving of a roving frame is to further draft a sliver into a fibre strand of finer count, the so called roving. This intermediate production step is necessary as the ring spinning machine is not capable of processing a thick sliver to a yarn of fine count. Moreover, the handling of a sliver in a ring spinning machine is still unsolved. This, because there is not enough space in the ring spinning machine for storing the bulky sliver cans in which the sliver is provide due to the poor strength of the sliver.

Ring spinning is essentially the process in which a roving of textile fibres is transformed into a twisted yarn by first performing a drafting and controlled elongation of the roving by which it is given the desired dimensions, which determines the yarn count of the yarn produced from it, and then giving the bundle of fibres of the roving, which have received only a slight twist in the preceding working and are still substantially parallel, an effective and necessary twist to give the yarn an adequate strength by making it pass along a path in high speed rotation between a fixed ring and a rotating spindle with the interposition of a ring driven by the spindle itself. The yarn thus twisted is collected by winding it on a bobbin, carried by the spindle, to form a spool which, when completed, is transferred for subsequent operation.

Yarn is steamed (heat set) in an autoclave after spinning so as to reduce or eliminate the twist liveliness (torque) and snarling tendency of the yarn and thereby facilitate the subsequent winding and twisting (folding) of the yarn and to avoid fabric distortion.