RAPIER LOOM
The rapier loom is a kind of shuttleless loom. It is a general-purpose loom for weaving small and medium-sized batches and frequently changing color fabrics. In the production process, the rapier loom has a high-speed weft insertion, and the consumption of the sword head and the rapier belt accounts for more than half of the total material consumption of the rapier loom machine. Therefore, how to effectively avoid the wear of the sword head and rapier band is very important to save production costs.
1, the hazard of wear
The sword head and rapier band are the key components of the rapier loom to complete the weft insertion task. During the weft insertion process of the rapier loom, the weft yarn is always actively controlled by the sword head, which makes the weft insertion error less and the reliability is high. Once the sword head wears, it will lead to the failure of weft insertion. In severe cases, it will even cause a large number of warp yarn breaks, which will affect the quality of the fabric.
The looms run 400 rpm, and the daily operation is 20 hours. The sword head reciprocates 960,000 times a day, and the sword head is inevitably worn during long-term operation. The most vulnerable parts of the sword head are the head, the wings and the bottom. Each time the weft is inserted, the sword head is subjected to the friction of warp, guide hook, sword board and guide rails when entering the sword and retreating the sword. When the two wings of the sword head are severely formed into a knife-edge shape, it is easy to cause the warp yarn to break, and even the sword head is not controlled by the guide hook and jumps out of the shed, forming a large number of broken ends.
2, the cause of wear
Production practice found that most of the damage of the sword head is caused by the breakage damage caused by the impact of the weft blade and the weft blade. This situation is caused by the movement of the gear and the rapier band for a long time to form a gap, which causes the movement of the sword head to be misaligned. For example, the GA749 type rapier looms have a relatively large slashing head, and the skeleton is made of plastic, so most of the damage is sent to the whistle. Most of the sword head breaks occur in the yarn blocking and yarn holding parts of the sword head.
The wear of the rapier head of the rapier is also closely related to the type of fabric. The wear of different types of sword heads varies from one to another, and the difference is large. The fabric with thick yarn number and high density has serious wear and short service life. The service life of the chemical fiber product sword head is shorter, because the head of the sword head reciprocates friction heat on the chemical fiber warp yarn, generates static electricity, and causes a hard layer of material to condense at the bottom of the sword head, and it is easy to hang up the warp yarn.
The composition of the slurry used for warp sizing also has a great influence on the degree of wear of the sword head. Different slurry components have different effects on the wear of the head of the sword.
▼
The craft structure of the rapier loom has a certain relationship with the wear of the sword head, especially the higher the height of the back beam and the greater the tension of the bottom warp yarn, the more serious the wear on the sword head. Because the tension of the lower warp yarn is large, when the shed is gradually closed, the lower warp yarn is lifted to increase the lifting force on the supporting sword head, and the pressing friction force on the guiding sword hook is larger, so the wear on the sword head is larger.
The transmission between the rapier band and the sword wheel is a special belt drive: the rapier band has a rectangular hole. During the transmission process, both the tooth root portion and the rapier with the hole wall contact teeth are engaged. The transmission has a friction transmission with the rapier band and the inner surface of the transmission wheel; the engagement angle of the rapier band to the transmission wheel is usually 120°~180°, and when the pitch is equal, the sword wheel and the rapier are transmitted. There is no relative sliding between the belts, and the pitch circle speeds of the two are equal; when the sword wheel is oscillating, the reciprocating linear motion of the rapier band is formed. Because the flexible composite tape has a certain rigidity, the rapier band needs to bear a certain bending stress when bending. Therefore, the curved pressure plate is designed to make the rapier band adhere to the surface of the transmission wheel, but the use of the curved plate makes the rapier band The latter half is greatly increased and thinned.
3. How to prevent wear and tear?
The tightness of the time between the rapier weft insertion movement and the warp opening movement directly affects the wear of the sword head. The opening time of the warp yarn is too early, the contact between the weft head and the warp yarn is relatively small, and there is more contact with the warp yarn when the sword is retracted. Therefore, the sword head and the warp yarn are more frictionally squeezed; likewise, the warp yarn opening time lags, and the sword retreats with the warp yarn. There will be less, but there is more contact between the weft head and the warp yarn, so the friction between the sword head and the warp yarn will be more.
When selecting the slurry component used for warp sizing, chemical slurry should be used to reduce the wear of the blade on the blade, which can greatly extend the service life of the blade. At the same time, further study of the coating technology of the sword head and enhance the wear resistance of the coating on the surface of the sword head is of great significance for extending the life of the sword head.
In the process structure of the loom, the height of the back beam is small, and the wear on the sword head is small. However, it is worth noting that the proper elevation of the rear beam is beneficial to improve the quality of the fabric. The definition of the grain texture and the depth of the grain peaks and valleys are much better than the back beam at 1000 mm. Therefore, a reasonable rear beam height should be determined. When weaving a dense fabric, the height of the back beam is generally about 1040 mm, so that the weaving can be carried out smoothly.
The quality of the coating of the sword head is very important for the use of the sword head. When the sword head enters and exits the shed of the warp yarn at high speed, the warp yarn generates alternating compressive stress on the surface of the sword head, causing the coating layer to be fatigued and peeled off. The peeling debris becomes a hard abrasive grain, and the abrasive grain wears on the blade head under the action of the warp yarn. Over time, a height difference is formed between the base body and the plating layer, and a cutting edge occurs, causing the warp yarn to be cut and stopped.
Reprint
