Major Problems and Solutions in Rapier Loom Weaving(5)
32. In rapier loom weaving, the cloth surface will sometimes turn out one side rough and backside smooth. What is the cause of this? How to prevent it?
This situation is easy to occur on the loom with ordinary guide hooks.
The heald frame is hoisted too low, and the lower warp sheet scrapes rapier race board.
The bottom of the gripper head gripper tape is worn with burrs.
Adjust the height of the warp leveling line.
Check and exchange the gripper head and tape.
Try to arrange production on rapier looms with floating guide hooks.
33. When the rapier loom is weaving fine tex high-density fabric, sometimes irregular and broken defects appear on the cloth surface. The flaws may not be easily found during grey fabric inspection but will become evident after finishing. Why? How to solve it?
Rapier looms generally use equal tension sheds. If the loom tension is too high and the weft yarn is too thin, the strength is too low, or the weft yarn is uneven, the shear stress generated by the warp yarn interlacing during the weaving process may lead to damage of the weft yarn weak spot. After finishing oxygen bleaching and the mercerizing process, broken defects will occur.
Check the strength and unevenness of the weft yarn. If the single strength is too low or strand unevenness is too severe, the weft yarn has to be changed.
Reduce loom tension appropriately.
Raise the backrest to keep the two layers warp sheet tension in a relatively big difference to reduce the shearing strength when interlacing.
34. How to prevent the looped weft at the shed exit when weaving fabric with elastic weft on the rapier loom?
Increase the number of waste warp yarns from 14 ends to 20-24 ends.
Strictly control the heald leveling time of the waste yarn heald frame, which should be 30° earlier than the ground warp leveling time.
Properly postpone the time of opening the receiving gripper and releasing weft.
35. What is the reason for the double weft in the left half of the fabric? How to prevent it?
The left weft scissors' cutting time is too late, and the weft yarn is not cut successful.
The weft gripper clamp's elasticity is too low, or there is flying fluff or waste yarn stuck in the gripper head, leading to the failed clamp of weft and delivery error.
Adjust the weft cutting time.
Increase the clamping force of the weft rapier head.
Check whether there are flying fluff and broken ends in the receiving gripper.
36. When the rapier weaving machine weaves high weft density fabrics, it is easy to cause the unstable cloth-fell, and the weft beating-up is not tight. What is the reason?
Rapier looms are generally equipped with equal tension sheds and high tension weaving. If the warp yarn tension is high in weaving high warp-density fabrics, the weft yarn is easy to reverse in the shed, leading to unstable cloth-fell, and the weft yarn cannot be beaten up tightly. When encountering this kind of species, unequal tension shed should be configured to make one layer of warp tight and the next layer loose to reduce the weft's reverse and enable the warp tightly wrap the weft. The specific operation is to lift the backrest high to keep the upper warp sheet in low tension and the lower warp sheet in high tension.
37. When weaving a single color weft fabric, how to properly handle the weft yarn to prevent color difference?
Should use 1:1 weft mixing or 1:1:1 weft mixing. Weft mixing aims to eliminate the influence on the cloth surface caused by weft color difference or uneven weft yarn. Introduce weft yarn from two or three cones to avoid the difference between the cones and the fabric's influence.