Color dot yarn: unique fancy yarn

Core summary:

Color dot yarn is one of the fancy yarns with a unique style. When making colored dots in the combing process, a rubbing process is required;

During combing, due to the addition of 1% of colored dots, the fibers must be fully combed, but the colored dots cannot be completely combed out to maintain the granular state of the dots. This is a contradiction in terms of technology.

Therefore, designing the combing and rubbing process is the key to spinning colored dot yarn.

1. Characteristics and key technologies of colored dot yarn

1.1 Characteristics of colored dot yarn

Color dot yarn is a yarn with one or several colored dots placed on the original white yarn or colored yarn. The colored dots in the yarn have a sharp contrast with the base yarn, light-colored dots with dark base yarn or dark dots with light base yarn, referred to as colored dot yarn.

Color dots are generally made of polyester material, and the diameter of the formed colored dots is about 3-4mm, granular, smooth surface, and the fibers are tightly combined. Fabrics made of dotted yarn require that the dots are randomly and evenly distributed, beautiful and lively, with a fresh style, adding strong visual dots to the original yarn. The color matching of dotted yarn requires prominent hue, bright brightness, and bright purity.

1.2 Key technologies of dotted yarn

1.2.1 Five necessary conditions for the carding machine to achieve carding

(1) The mutual configuration and direction between the two needle surfaces of the carding needle cloth.

(2) The control and release of the needle teeth on the fiber.

(3) The speed and spacing between the two rollers.

(4) The form of fiber passing and the retention time.

(5) The magnitude of the fiber separation force.

1.2.2 Two key technologies of dotted yarn

The dotted yarn is made by mixing dots with base yarn raw materials and spinning them into yarn. The dots of dotted yarn are both made on the carding machine and combed on the carding machine. There are two key technologies:

(1) The kneading process.

(2) The dotted combing process.

In terms of making colored dots, the reverse control of the five necessary conditions of the carding machine is followed, and the positive control is followed during carding.

2. Key points of the process of rubbing colored dots into dots

2.1 Characteristics of the rubbing dot process

Colored dots are generally made using cheap raw materials such as cotton waste and scraps from various fibers in the spinning process, and are spun using special processes. Generally, cotton-type chemical fibers such as polyester and acrylic or pure cotton spun choppers are used.

The size and tightness of the dots are related to factors such as the nature, specifications and carding process of the raw materials used.

In general, when the fiber rigidity is small, the fiber is fine, and the friction factor between fibers is large, the knot is relatively large.

The process of making dots is to fully rub the fibers between the two needle surfaces of the carding machine, so that the fibers form a ball shape and a very random loop arrangement, and some fibers extend out of the dot body, which has the conditions to connect with the external fibers. Dots exist as decorative yarns in fancy yarns, requiring bright colors and prominent hues.

Color dots need to be processed using a modified special carding machine. It is not to comb the fibers, but to process colored cotton knots. In the process, the color dots are first processed using a modified special carding machine, and then the color dots and the selected fiber raw materials are made into color dot cotton strips through the cleaning and combing process, and then they are combined with the prepared ordinary cotton strips in the drawing process, and then made into yarn through the coarse and fine winding process.

2.2 Key points of rubbing into dots carding process

Conditions for rubbing fibers on the carding machine: larger spacing, sparser needle clothing configuration and stronger control ability. The transformation of fibers into color dots mainly depends on the rubbing and looping of fibers between needle clothing.

The processing equipment for fiber dots is generally modified from the A186 series carding machine. The three-roller stripping device is removed, and a stripping roller covered with curved foot needle clothing is installed above the doffer, and the spacing between the doffer is controlled at 2-4mm. The doffer needle surface always maintains a layer of fiber net. The fibers on the cylinder are repeatedly rubbed and turned into dots under the joint action of the doffer, cover plate and licker-in roller. In production, there should be a large speed ratio between the licker-in roller and the cylinder, generally 2.3:1.

In the process configuration, the licker-in roller should not only transfer the combed fibers to the cylinder, but also peel off the knots that have been twisted on the cylinder needle surface. Under the action of centrifugal force, the dots fall at the entrance of the small leak bottom and are then taken out manually. The main processes that need to be adjusted for combing cotton are: reverse installation of the cover plate, cross-configuration of the needle teeth on the two needle surfaces of the cylinder and the cover plate, canceling the combing effect, and making the fibers float between the two needle surfaces.

The spacing between the cylinder and the cover is 0.56mm, which increases the kneading of the fiber to form dots;

The spacing between the cylinder and the doffer is 1.1mm, so that the fiber on the cylinder needle surface repeatedly enters the cylinder cover, and after repeated kneading into knots, it is transferred to the doffer needle surface. The fiber also returns to the doffer many times, so that the dots are kneaded more tightly and then peeled off from the doffer;

At the same time, the dust removal knife is removed, the small leak bottom is extended, and the amount of cotton drop is reduced; the additional combing original parts are cancelled to reduce the combing capacity; the suction device is cancelled to provide conditions for kneading;

The cover, doffer and cylinder of the carding machine are controlled to start and stop respectively, and the raw materials are repeatedly kneaded for a long time between the cylinder cover to form knots, which is convenient for stripping outside the machine after the dots are formed. The specific process configuration of the carding machine color dots production is shown in Table 1.

3. Key points of the combing process of colored dot yarn

3.1 Combing characteristics of colored dot yarn

The cotton blending of colored dot yarn should be selected from raw materials with better maturity, which are pre-treated and cross-blended with some raw materials. The biggest difference between colored dot yarn and conventional varieties is that colored cotton knots are added to it, and colored cotton knots cannot be removed, which is the key to the configuration of the combing process. The process of colored dot cotton strips should "maintain the colored dots and take into account the combing of other cotton knots". The combing spacing between the cover plate and the cylinder generally adopts the process principle of neither loose nor tight.

Strong combing not only makes the colored cotton knots larger or smaller, but also has the possibility of excessive combing force, which completely combs the colored dots into single fibers. This not only affects the number of colored dots, but also causes the base color of the colored yarn to change and form interference. Although too weak combing does not harm the colored dots, other fibers are prone to form unwanted heterochromatic cotton knots due to poor combing, which is the key point to prevent for colored dot yarn.

3.2 Carding process of colored dot yarn

Measures should be taken at the small leaking bottom of the carding machine to minimize or eliminate the colored dots;

The cover speed should be slowed down, generally controlled at 78~80 mm/min is better; the cover flower should be reused in time;

At the same time, the combing element should be flat, smooth and sharp, otherwise the fiber cannot be smoothly transferred and stripped; the raw sliver quantity should be appropriately larger, generally controlled at about 25g/5m, because there are knots in the fiber net, and the cohesion between them is small. The raw sliver quantity is larger, which is conducive to improving the cohesion;

In order to prevent the difficulty of cotton net forming, a cotton net support plate and apron cotton guide device are used;

Cylinder speed 330r/min, licker-in roller speed 785r/min, doffer speed 21r/min, cylinder-doffer spacing 0.13mm, cotton feeding plate-licker-in roller spacing 0.18mm, cylinder-cover spacing 0.20, 0.20, 0.18, 0.18, 0.20mm. For details, please refer to the actual process design as shown in Table 3.

(1) The production process and spinning process of color dot yarn are two completely different processes. The production of color dots requires full rubbing to form dots. The color dots need to be protected during the spinning process. In production, other fibers must be fully combed, but the dots cannot be completely combed. The combing process design is the key to spinning good color dot yarn.

(2) There are two key technologies for color dot yarn: rubbing to form dots and color dot combing process. The production of color dots follows the reverse control of the five necessary conditions of the carding machine, and the combing follows the positive control.

(3) The evaluation of color dot yarn is fuzzy and mainly relies on sensory detection. The process of color dot production and combing protection is random, which is the focus of color dot yarn process design and quality control.