Spinning - Textile Section

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The characteristics of the fibers determine the greater or lesser suitability of the yarns for the realization of a given fabric.

Depending on the chemical-physical properties of the fibers, the spinning processes differ in spinning carded, combed spinning, open end spinning and extrusion spinning.

Carded spinning (selfacting)
In this spinning system virgin and / or regenerated wool fibers and others of origin are used
animal, vegetable, chemical, waste from intermediate processing of combed wool.
They are generally short cut fibers. These materials are normally used in mixed with
other longer fibers that help improve the technological characteristics of the yarn.
Spinning used
The manufacturing process includes the following stages:
a. preparation of the mixture for carding, which consists in the realization of the mixture with the various
components different in color and / or quality and quantity;
b. carding, with which the material prepared in preparation is subjected to repeated actions
mechanics whose purpose is to fray the fibers, parallelize them and, at the same time, mix
the various components, both from a qualitative and quantitative point of view and in terms of color.
Carding is composed of an assortment of three groups of machines connected together:
1) card to break with automatic loader,
2) cross card,
3) divider.
Wicks (prototypes of false twisted threads) come out of the divider, ready to be passed on to the process
c. spinning, which can be done on spinning mills intermittent (selfacting, fig. 2), or in
continuous (carded ring), has the purpose of transforming the wicks in yarn, giving them an iron to reach the desired title
and a twist to the fibers that can be left (S twist) when the twist propellers they rise from right to left or right
(Z twist) when the propellers rise from the left to the right (see figure 1). At the end of
each spire in the case of intermittent spinning and continuously in the case of the ring, the yarn is wound on special tubes.
The yarns thus obtained are soft and slightly fluffy, suitable for both the clothing sector
traditional as for knitwear, especially for the autumn / winter period.
Comb spinning (ring or ring)
This spinning system requires operations that transform the chosen part (top) of the wool into yarn,
after the fiber mass has been purified of the vegetable parts and have been eliminated, by combing,
short fibers.
Combed yarns, both in natural and synthetic fibers, are mainly used for
clothing, both traditional and knitted. They are smooth, quite regular in the section, rather
cold and free of fluff, since the fibers that make them up are longer than those
used in carded and more parallel yarns.
The preparation for worsted spinning is composed of:
1. carding, which occurs on so-called comb cards that collect the fleece in ribbons.
This operation eliminates the greatest quantity of vegetable parts, forming a continuous web of
stretched fibers;
2. actual preparation for spinning, consisting of a mixer, a comber and
a series of successive passages through comb drawing frames called intersecting, with couplings
and ironing of various ribbons, necessary to give them greater regularity and homogeneity.
The tapes will eventually feed a passage to the finishing bench that produces reels of wicks,
ready for the transition to real spinning: ring (fig. 3).
3. Ring or ring spinning constitutes the last operation of the entire process and has the purpose
to give a twist and a last stretch to the wick, so as to give it the resistance characteristics,
elasticity, strength and torsions required. This can also be done on some
types of wick coming from the carded spinning process.
used machine
Open end spinning
The open end system (fig. 4) developed in the spinning of cotton-cut fibers. This system
realizes the condensation of the fibers using of the internal throat located on the periphery of a
small rotor (turbine). On the machine it is prepared one rotor for each wire head. The tape o
previously prepared feeding wick, it is disaggregated (frayed) in the individual
fibers and reaches the rotor. The fibers have, with the conveyor belt, a very low speed
which gradually increases undergoing a considerable stretch. Upon arrival in the rotor this, with its rapid rotation,
subjects the fibers inside to a high centrifugal force which pushes them towards the periphery
where the surface is profiled in a particular way and such as to give the yarn an adequate shape
and such as to straighten the fibers. These overlap and condense, abandoning the
throat of the rotor with a certain twist and with a speed much lower than the peripheral one of the turbine,
resulting in a continuous spinning where the yarn is wound on bobbins.
Spinning of chemical fibers (extrusion)
The spinning of chemical fibers, whether artificial or synthetic, starts from a polymer (substance of
base) made liquid by solution or melting, which is extruded through a multi-hole die.
The continuous burrs thus obtained are solidified. Wanting to make analogies we proceed as
for the spider that weaves its web or as the silkworm that produces the thread to create its own
cocoon. The result is a continuous filament which can, if necessary, be stapled for later
be mixed with other discontinuous length fibers, both in the carded and combed system. Give her
dies It is possible to obtain single-burr threads (i.e. consisting of a single burr) or yarns (called multi-burr),
twisting between them several continuous burrs, depending on the yarn count to be reached.
The analysis and control of textile products, carried out with various laboratory devices,
they guarantee the accurate detection of the quality standard, both in the various stages of the supply chain
textile than on the packaged garment.
They depend on the regularity check carried out during the production of the yarn for knitting or for fabrics
the results of the subsequent operations and only with the control over the finished fabric can it be guaranteed
packer first and then to the consumer, a certain quality standard of suitability for use.
For these reasons, much attention is paid to chemical and technological control
yarns and fabrics, keeping in mind the typology of the various defects and always having
both the obvious ones are present - that is, that can be seen and appreciated with
the normal diligence of the operator - that hidden ones, which can occur
only after use or after a certain period of time.
The checks on yarns and fabrics of a chemical nature concern the following aspects:
a. recognition of qualitative and quantitative fibers, on yarns and on
b. uniformity of color on the fabric;
c. degree of color fastness (resistance) to light both artificial
that diurnal, to the various types of sweat, to the various types of water
(rain, sea, etc.), punching down, rubbing, etc.
d. degree of impermeability;
is. Flash;
f. breathability;
g. dimensional stability of the fabric to the various types of washing.
The most significant technological checks concern:
to. length and fineness of the fibers;
b. twists and yarn count;
c. regularity of the section of the yarn and any impurities;
d. dynamometric resistance of yarn and fabric;
is. square meter or linear weight and fabric height;
f. burst resistance for knitted fabrics;
g. weaving of traditional and knitted fabrics;
h. resistance to sliding seams (before or on the garment)
the. resistance to wear and pilling of fabrics;
j. number of burrs on continuous filament synthetic yarns.

The analyzes for the research of the indicated defects are only some examples of the most recurrent checks
which are carried out on both classic and knitted fabrics. It is clear that for special fabrics intended
other types of analysis are foreseen for particular uses or for specific defect searches.

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