The rapier loom is a kind of shuttleless loom. It is a more general loom for weaving small and medium batches and frequently changed color fabrics. During the weft insertion process of the rapier loom, the weft is always actively controlled by the rapier. Resulting in fewer weft insertion errors and high reliability. In the production process, the rapier looms high-speed weft insertion, and the consumption of the rapier head and the rapier belt accounts for more than half of the total material consumption of the rapier loom. Effectively avoiding the abrasion of the rapier loom is very important to save production costs. Moreover, once the sword head is worn, it will cause weft insertion failure, and in severe cases, it will even cause a large number of warp yarn breakages, which will affect the quality of the cloth surface.
1. Causes of wear
Suntech Research Institute found that most of the sword head damage was caused by the impact of the weft feeding sword head and the weft receiving sword head during the work of the loom. This situation is due to the long-term wear and tear of the transmission device and the rapier belt to form a gap that leads to the movement of the sword head. The breakage of the sword head mostly occurs in the yarn blocking and holding parts of the sword head.
The wear of the sword head of the rapier loom is also very much related to the type of fabric. The wear of the sword head of different varieties is different, and the difference is quite large. For fabrics with thick yarns and high warp density, the sword head wears more severely and has a short service life. The service life of the sword head of chemical fiber products is shorter. This is because the sword head is rubbed back and forth on the chemical fiber warp to generate static electricity, which causes a layer of hardened substance to condense on the bottom of the sword head, which makes it easy to hang the warp.
The composition of the size used in the warp sizing also has a great influence on the wear of the sword head, and different size components have different effects on the wear of the sword head.
The technological structure of the rapier loom is also related to the wear of the sword head, especially the higher the height of the back beam and the greater the tension of the underlying warp yarn, the more serious the wear on the sword head. Because the tension of the lower warp yarn is high, when the shed gradually closes, the lower warp yarn will lift to increase the lifting force of the supporting sword head correspondingly. The greater the pressing friction force on the guide sword hook, the greater the wear on the sword head.
2. How to prevent wear and tear?
Suntech’s loom machine has made great improvements in the selection of sizing material, the height of the back beam of the loom, and the coating of the looming head. In the high-speed operation of ordinary rapier looms, the closeness of the time coordination between the rapier weft insertion movement and the warp shedding movement directly affects the wear of the rapier head. The warp opening time is too early, the weft feeding sword head has less contact with the warp yarn, and the warp yarn will be contacted more when the sword is retracted, so the sword head and the warp yarn friction and squeeze more; similarly, the warp yarn opening time is lagging, and the retracting sword contacts the warp yarn. There will be less, but there is more contact between the sword head and the warp yarn in the weft, so the friction and squeeze between the sword head and the warp yarn will be more at this time.
Therefore, Suntech chooses a slurry with less wear on the sword head, which can greatly extend the service life of the sword head. At the same time, further research on the coating technology of the sword head to enhance the wear resistance of the coating on the surface of the sword head is of great significance for prolonging the life of the sword head.
Suntech found that in the process structure of the loom, the height of the back beam is small, 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 cloth surface. Therefore, after a long period of practical research, Suntech has determined a reasonable height of the rear beam, which greatly reduces the wear of the sword head.
Finally, the coating quality of the sword head is of great significance to the use of the sword head. When the sword head enters and exits the shed formed by the warp yarn at high speed, the warp yarn generates alternating compressive stress on the surface of the sword head, causing fatigue wear and peeling of the coating. The flaking debris becomes abrasive grains with high hardness, which will cause abrasive wear to the sword head under the action of the warp yarn. Over time, the height difference between the substrate and the plating layer will form a cutting edge, which will cause the warp yarn to be cut and the machine will stop. For improvements in this area, Suntech is still studying to complete a breakthrough.