What is the specific process when weaving cowboys?

The production technology of denim is quite unique. It is a product that warp yarns are dyed and sized with indigo and then woven. (1) dyeing and sizing. There are three kinds of indigo dyeing of denim warp: rope dyeing, piece yarn dyeing and loop dyeing. The first two are connected with sizing, and the latter is dyed before sizing. (1) Rope-like dyeing and sizing: on the ball warping machine, 350 ~ 400 warp yarns are arranged into a plurality of rope-like strips with the length of10000 ~15000m, and then 12 ~ 36 rope-like strips are sent to the continuous dyeing machine side by side, dried and wound into a tube after dyeing. On the long-chain warping machine, rope-like warp yarns are dispersed and wound into a single warp yarn. According to the total number of required warp yarns, they are wound into warp beams. The disadvantages of rope dyeing are insufficient dyeing, oxidation and water washing, and huge equipment, which generally covers an area of about 1000m2 and is about 8m high. ① Yarn dyeing and sizing: Yarn dyeing is commonly known as warp beam dyeing. It means that the warp yarns are made into pieces after warping, rather than being sent to the dyeing machine in multiple strands. This dyeing is characterized by uniform warp arrangement, rapid and uniform coloring and oxidation. In addition, the investment is small, occupying about half of the rope dyeing machine. The disadvantage is that cotton yarn is arranged in a single line and easily entangled, especially under the liquid surface. Because of the slow dyeing speed, two dyeing machines can also be combined with a sizing machine, which can double the efficiency, that is, the double warp beam yarn dyeing machine. At present, yarn dyeing machines are produced by Sarazzi Company in Switzerland and zell Company in Germany. (3) Hanging ring dyeing: This method uses a dyeing tank, and the warp yarns are dyed repeatedly in this tank until the depth requirement is reached. The dyeing and sizing process is as follows: alkali boiling (or wetting): sodium hydroxide 2-3g, alkali-resistant penetrant 1g/L, temperature 95- 100, time 20-30s, indigo dyeing: indigo (2+χ) g, sodium hydroxide 2. 5g, sodium hydrosulfite (85%) 2~3g/L, bath volume about 1000L, room temperature time 20S, because indigo is on cotton fiber. Moreover, the fastness to high-temperature dyeing is poor, the dosage of sodium hydrosulfite is large, and the color is dark red, so it is necessary to dye at room temperature for many times. This is the dyeing characteristic of denim. The ventilation oxidation temperature is 80 ~ 100 s at room temperature. In order to obtain pure color light, indigo is dyed by natural oxidation without oxidant ventilation. Because indigo is easy to reduce and difficult to oxidize, it is also repeatedly oxidized. The water temperature is room temperature first. On the one hand, the floating color, residual alkali and impurities are removed in the water washing process, and on the other hand, the oxidation can be continued to make it fully oxidized. In order to save indigo dye, black sulfide can be used instead of alkali boiling as the base material, and it can be dyed light gray first and then dyed with indigo. After dyeing, if the color of the finished product is red, the dosage of sodium hydroxide can be reduced, and if the color is green, the dosage of sodium hydrosulfite can be reduced, which generally does not destroy the colorless state of indigo. (2) weaving. At present, shuttleless looms are widely used in denim weaving in the world, accounting for more than 80%. Among shuttleless looms, projectile looms are the most, followed by rapier looms and air-jet looms. The heavy denim machined by shuttle loom can reach 55 1g/㎡, while that woven by air-jet loom can only reach 407g/㎡. Due to the different warp and weft colors, yarn defects such as uneven weft will be obviously exposed on the fabric surface. In addition, the original yarn is sometimes used as weft, because yellow and white yarn can also cause weft block. In order to prevent this phenomenon, a weft mixing device can be used, or the weft can be dyed light gray. Weaving adopts large warp beam and large winding. This is because the yarn count is thick, the turnover is large, and the doffing cycle is fast, so it is necessary to adopt a large warp beam, generally 800mm in diameter and 560 mm in winding shaft. If it is separated from the machine body, the big package can reach 1500mm (denim is about 600m), but special vehicles and verification equipment are needed. The change of weft tension in weaving will also produce fabric crosspieces. Although the single weft insertion of shuttleless loom can avoid the tension difference between shuttles, in order to eliminate the tension difference between the number of bobbin yarns and the winding quality of bobbin yarns, it is necessary to increase the yarn storage device. The yarn tension provided by the weft accumulator to the weft gripper should be consistent, which is especially important for elastic fabrics. Denim yarn count is thick, there are many kinds, and the warp tension is high. In order to make the opening clear, the heald frame movement must be positive. Some shuttleless looms still use spring healds, which are not suitable for thick fabrics. Therefore, an external pedal device can be selected, and the pedal opening moves through the compound pedal, so that the movement of the heald frame can be accurately controlled. The movement of pedal is driven by rotor rod, pedal rod and heald frame transmission connecting rod, and equipped with shed leveling device, which can adjust all heald frames to the same height. The change of warp tension in weaving process will also cause weft defects (especially weft breakage). This problem can be solved by using an external pedal device. Because when the weft yarn breaks and finds the shed, the warp yarn let-off, winding and beating-up will not move. The pedal can move independently, and the warp tension will not change. The device is equipped with separate motor drive devices on picano 174 PGWMA rapier loom and Toyoda-Sulzer PU130 MWe10D, R shuttle loom, all of which are patented devices. (3) after finishing. The shrinkage rate of denim grey cloth is above 10%, and it can only be reduced to below 3% through pre-shrinkage. Generally, the shrinkage is required to be within 1.5% ~ 2%. Technological process: BF-7658 enzyme used for desizing has good effect, soft hand feeling and no fading. After making clothes, they are washed with volcanic rocks, sodium hypochlorite, acid, rubbed and sanded, and made into stone washing, snowflake washing (also known as marble washing), sanding and other varieties. At present, there are new products such as cellulase biological washing. Baidu has,,,,,