There are many classifications of looms. According to the weaving method, they can be divided into shuttle looms and shuttleless looms. The weft insertion of a shuttle loom is a loom that uses traditional wooden shuttles or plastic shuttles for weft insertion. Due to the large size and heavy weight of the shuttle, the shuttle is repeatedly projected back and forth, causing the machine to vibrate, noise, energy consumption, vehicle speed is slow, and efficiency is low.
There are also various weft insertion methods for shuttleless looms, such as rapier, air jet, water jet, projectile and multi-shed (multiphase). The air-jet loom adopts a shuttleless loom that uses a jet of air to draw the weft through the shed.
1. Historical development
(1) In 1949, Czechoslovakia first made an air-jet loom. Due to the lack of control measures for the diffusion of airflow, the width of the woven fabric was only 45cm.
(2) In 1956, a combined piping sheet was developed to limit the diffusion of airflow, which made a breakthrough in jet technology.
(3) In 1963, the Netherlands developed the auxiliary nozzle weft insertion technology, which greatly increased the width and speed of the loom. 04 In the 1970s, a new form of restricting airflow diffusion-special-shaped buttons came out, which is a new development in the range and quality of fabrics woven by air-jet looms.
2. The principle of weft insertion
Air jet weft insertion is to use air as the weft insertion medium to draw the weft yarn with the compressed air jets to generate frictional traction, take the weft yarn through the shed, and achieve the purpose of weft insertion through the jet generated by the air jet. The characteristics of air-jet weft insertion The characteristics of air-jet weft insertion are high speed, large tension, and small shed, which require relatively high requirements for raw yarn and semi-finished products. Air-jet weft insertion is a passive weft insertion method. The tension of the weft yarn is small when flying over the shed, and there is no control. Therefore, it lacks sufficient traction for the weft yarn with high linear density or fancy yarn. At the same time, the warp yarn shedding state has a great influence on the quality of weft insertion, and it is easy to produce fabric defects such as weft shrinkage and weft return.
Among several shuttleless looms, the air-jet loom is the one with the highest speed. Due to the reasonable weft insertion method, the higher weft insertion rate, the simple and safe operation, the wide variety of adaptability, the low material consumption, and the high efficiency. , High speed, low noise, etc., has become one of the most promising new cloth machines. As the air jet loom adopts the air-flow weft method, the biggest disadvantage is the high energy consumption.
4. Scope of application and fabric varieties
The early air-jet looms had a very small range of adaptation, mainly producing white grey fabrics, with small fabric widths, slow speeds, large fabric limitations, and low fabric quality. However, since the early 1980s, with the development of air-jet looms with special-shaped reeds and relay weft insertion technology, as well as the application of electronic computers, sensors and frequency conversion technology, the speed of the air-jet looms and the automatic monitoring of the loom have been greatly improved. Level, especially the rapid development of air-jet looms in the past 10 years, has made air-jet looms have many advantages such as high quality, high speed, high output, and high level of self-control, and the range of varieties has been greatly improved. The width of the air-jet loom has risen from 190cm, 280cm to 340cm, 360cm, and 400cm; the main nozzle has been increased from a single nozzle to double nozzles and four nozzles; the multi-color weft insertion system controlled by computer software can carry out 4 colors to 12-color weft selection; the raw material of the weft yarn can be chemical fiber filament, chemical fiber staple fiber, pure cotton yarn, wool yarn, glass fiber yarn, various fancy yarns, etc.; product varieties range from high-density, fine-thin and high-end fabrics to thick and high-density Both thick and thick fabrics can be produced. DORNIER air-jet looms have been used to produce industrial fabrics such as filter fabrics, emery cloth twill fabrics, steaming fabrics and glass fiber wall coverings. The new air-jet looms from Picano from Belgium and Tsudakoma from Japan are also equipped with electronic jacquard, dobby and other shedding systems to adapt to the production of various fabrics.
5. Comparison with other shuttleless looms
Rapier looms have unique advantages in variety adaptability, but the weft insertion rate is lower than that of air-jet looms, only 1400m/min, which is about 50% of that of air-jet looms; the silk return rate is higher than other shuttleless looms Loom. At present, rapier looms are mainly used for the production of small batches and a variety of weft fabrics such as decorative objects. The projectile loom has advantages in weaving extra-wide fabrics and high-end decorative fabrics, but the weft entry is lower than that of the air-jet loom, which is 1200m/min; the energy consumption for projectile acceleration only accounts for 15%, and the energy consumption Unreasonable; high requirements for the material performance of the torsion shaft of the shuttle and the weaving precision of the mechanism; expensive, and a large one-time investment cost. Water-jet looms have limitations in the quality of weaving, and are only suitable for the weaving of hydrophobic yarns such as synthetic fibers and glass fibers. The relevant components on the loom should be made of stainless steel. Multiphase looms Multiphase looms can weave with extremely high weft insertion rates. But it can only produce simple ordinary fabrics, and the power consumption per square meter of fabric is higher than other shuttleless looms.
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