Top→Mixed sliver→Needle comb→Roving→Spinning→Bundling→Skewing→Inspection→Packing of finished products.
Spinning fibers into yarn generally goes through the main processes such as cleaning, carding, drawing, roving, and spinning. Yarns and threads used in high-end products also require additional combing processes.
The production of cotton yarn with different requirements requires different processing procedures, such as spinning pure cotton yarn and polyester-cotton blended yarn. Due to the different raw materials used, the physical properties of various raw materials are different, and the product quality requirements are different. Different production processes are required. (With the renewal of modern equipment, there are also various degrees of adjustments in the process. The equipment can merge some of these processes together, making the actual observation less work that was originally necessary)
The difference between weaving yarn and knitting yarn
Woven yarn requirements: high strength, less neps.
The knitting yarn is not as strong as the woven yarn, but the detail requirements are high, and the twist is not as high as the woven yarn.
Generally, the twist coefficient of woven yarn is around 380, while knitting yarn only needs around 340.
For example, for 40s single yarn, the twist of woven yarn is 99 twists/10cm, while the twist of knitting yarn is about 88-89 twists.
1. Twist
Twist generally refers to the number of twists/m. Different counts have different twists. In order to compare the twists of yarns with different counts, the concept of 'twist coefficient' is commonly used.
Yarn twist
Twisting is one of the purposes of spinning, and the amount of twisting is an important indicator of yarn performance, which is generally expressed by twist. Twist refers to the number of twists per unit length of the yarn (that is, the number of spiral turns). The unit length varies with the type of yarn, and the unit of measurement can be expressed as 'twist/10cm' or 'twist/m'. The former is used for cotton and cotton-type chemical fiber yarns, and the latter is used for worsted yarns and yarns. Twist measurement of chemical filament yarn. Twist affects yarn strength, rigidity, flexibility, elasticity, shrinkage and other indicators. As the twist of the yarn increases, its strength increases, but the twist cannot exceed a certain value, otherwise its strength decreases. This certain value is called the critical twist of the yarn. Yarns of different raw materials have different critical twists. The softness, elasticity and shrinkage of the yarn are also closely related to the twist. Generally, under the premise of meeting the strength requirements, the smaller the yarn twist, the better, because the increase in the twist will make the yarn feel harder, decrease the elasticity, and increase the shrinkage rate. This is the filament yarn generally try not to twist as much as possible. Or for the sake of less twisting. In addition, the twist also affects the volume, weight and diameter of the yarn, and the twisting effect increases the tightness of the yarn. Within a certain range, the volume weight of the yarn increases with the increase of the twist, and the diameter of the yarn decreases with the increase of the twist, so that the coverage and comfort of the fabric will change.
In short, yarn twist should be selected according to different fabric uses. If the warp yarn needs to have higher strength, the twist should be larger; the weft and knitting yarns need to be soft, and the twist should be smaller; for woven and knitted pile fabrics, the twist should be smaller to facilitate raising; thin and cool Crepe fabrics are required to have the characteristics of smoothness, stiffness and coolness, and the twist of the yarn should be larger.
Twisting direction of yarn
The twisting of twisting has a direction, which is called the twist direction, which is the inclination direction of the fibers in the twisted yarn or the inclination direction of the single yarn in the twisted strand. There are two twist directions: Z twist and S twist. If the fiber in the single yarn or the single yarn in the strand is twisted, the tilt direction is from bottom to top, from right to left is called S twist, also called right hand twist or right twist; if the tilt direction is from bottom to top Up, from left to right is called Z twist, also called left hand twist or left twist. The method of expressing the twist direction is stipulated. Single yarn can be expressed as: Z twist or S twist. In actual use, single yarn mostly appears as Z twist; strands can be the same or opposite to the twist direction of single yarn. Both of the twist directions must be expressed, so it can be written as: the first letter indicates the twist direction of the single yarn, and the second letter indicates the twist direction of the strand. After twisting twice, the third letter indicates the direction of twisting. For example, the single yarn is Z twist, the first twist is S twist, and the second twist is Z twist. The twist direction is expressed as ZSZ twist. In fact, the twist direction of the strand is opposite to that of the single yarn, and the strength, luster, and hand feel are better. Therefore, the actual use of strands is mostly S twist.
The twist direction of the yarn has a great influence on the appearance and feel of the fabric. Reasonable use of twist direction can obtain various fabrics with ideal appearance effects. Such as plain weave fabric, the warp and weft yarns have different twist directions, the surface of the fabric has the same reflection, good gloss, and the fabric is bulky and soft. For twill fabrics such as gabardine, when the warp yarn adopts S twist and the weft yarn adopts Z twist, since the twist direction of the warp and weft yarns is perpendicular to the twill direction of the fabric, the reflection direction is consistent with the twill weave, so the texture is clear. When several S-twisted and Z-twisted yarns are arranged alternately, the fabric can produce a hidden stripe effect, just like some tweed fabrics. Of course, when yarns with different twists are twisted together to form a fabric, a ripple effect will be produced.
Twist coefficient
When the twist coefficient is 360±36, the twist is larger, suitable for weaving
When the twist coefficient is 330±36, the twist is small, suitable for knitting
When it is between 330 and 360, it can be used for both weaving and knitting
The effect of twist of chemical fiber yarn on quality
The twist of the chemical fiber yarn has a great influence on the strength, softness and stretchability of the chemical fiber yarn. Increasing the twist within a certain range will increase the strength. If the twist exceeds the limit, the strength will be weakened. , The twist of chemical fiber yarn is small, it is soft, and the strength is reduced.
2. Strength and strength of chemical fiber yarn
The strength of chemical fiber yarn is closely related to the fastness of fabric and production efficiency. The strength of chemical fiber yarn is the basis of fabric strength and elongation. Therefore, the strength and elongation of chemical fiber yarn is an important indicator of quality, so it must have appropriate strength and elongation. . The strength and elongation of chemical fiber yarns vary according to their raw materials, degree of processing, and fiber arrangement. The quality of the raw materials is good, the fibers are arranged neatly, the twist is appropriate, and the strength and stretchability of the chemical fiber yarn will be good. The strength test of chemical fiber yarn is divided into two types, one is single yarn strength and the other is strand strength.
3. Moisture regain of chemical fiber yarn
Moisture regain: 0.4% of polyester yarn, 2% of acrylic yarn, 4.5% of nylon yarn, 5% of vinylon yarn, 0% of polypropylene yarn, 0% of polyvinyl yarn.
