Analysis of the phenomenon of oblique folding printing on fine square mesh screen 1

Dark folding printing can be divided into two situations: one is that the folding printing is formed earlier, and it is already formed after the mesh is woven. When the mesh is loosened, the folding printing can be found on the mesh surface. After the mesh is tightened, the folding printing disappears and cannot be seen; Another type of folding marks is formed relatively late. After the mesh is woven, no folding marks are formed. Instead, after the mesh is rolled onto the roll, a dark folding mark is formed on the roll. Even if the mesh is loosened, it is not easy to notice the folding marks on the mesh surface. This kind of dark folding mark does not appear within a dozen meters after hanging the mesh, usually only after 20 meters. Dark folding printing poses a serious threat to product quality, which is difficult to detect and eliminate, and has a relatively high probability of occurrence.

1.On which type of weaving machine is it easy to produce diagonal creases on square mesh? Why?
It is easy to produce diagonal creases on square mesh when weaving on an imitation Japanese flexible rapier loom, while it rarely happens when weaving on an imitation German loom.
This is because the body of the imitation Japanese loom is longer, it has a single-cloth beam and the weaving time is 1/3 to 1/4 of the net winding time. When the warp yarns are being combed, they produce large elastic elongation, causing the metal net on the winding roller to instantly relax. Additionally, the elastic deformation values of the metal wires in different parts of the net surface are not consistent, making it easy to produce diagonal creases on the winding roller.
2.Why is it easier for diamond-shaped mesh to appear skewed in twill weave than in plain weave?
(1)The stiffness of plain weave is better than that of twill weave.
(2)Plain weave is equipped with basic tension less than twill weave.
(3)When carding plain weave, the opening tends to overlap or is very small, while twill weave has two ends with maximum opening and maximum tension that can easily reach 0.6p or above.
(4)The shrinkage rate of twill weave is smaller, and the locally stretched warp yarns will not tighten quickly, so the inconsistency in mesh tension is maintained for a longer period of time.
(5)After the tension is released, twill weave is prone to twisting and skewing, while plain weave does not have this phenomenon.
3.What is the impact of the ratio of holes to yarns on the formation of skewed creases?
The size of the ratio of holes to yarns directly affects the size of the carding force, which in turn affects the elasticity and elongation of all warp yarns. When the carding force increases, the amount of backward shift of the weaving mouth during carding increases, the degree of net relaxation increases, and the possibility of forming hidden creases on the winding roller increases.
The size of the ratio of holes to yarns directly affects the natural inclination of the twill net. Twill nets with large natural torsional twist are extremely prone to hidden creases.
When the ratio of holes to yarns is between 1.4 and 1.8, the natural torsional twist of the twill net is the largest, making it the most prone to skewed creases.
4.What are the factors that cause inconsistent tension on the net?
(1) Large deviation in warp wire diameter; large differences in warp wire mechanical properties.
(2) Some warp wires undergo plastic elongation during the weaving process.
(3)Inconsistent thickness of the net.
(4)Uneven installation or adjustment of warp beam, breast roll, web support plate, or roll-up roller.
(5)Inconsistent height position of the two sides of the beam.
(6)Inconsistent twisting time on both sides of the beam.
(7)The edge of the metal net on the roll-up roller is too high compared to the net surface.
(8)Local weft skewing or wrinkling occurs on the net surface.
(9)Local thickness and roughness of the weft insert; thick weft yarn, tight weft, weft insert cannot sway flexibly.
(10)Wire clips at local positions on the steel stake, and local box plates twisted crookedly.
(11)Local wear and loose warp wires at the sword head.
(12)Large differences between warp wire width and net width (greater than 30mm).
(13)The warp wire on the warp roll is not flat, causing the length of the warp wire on the warp roll to be inconsistent every circle.
5.the influence of rolling time on skewing:
Rolling time has an influence on skewing, but it is not the determining factor. The amount of backward movement of the weaving mouth during carding is much greater than the amount of rolling. The time required for rolling is much longer than the time required for carding. Therefore, the correct rolling time only has a small impact on overcoming skewing.
6. Does the warp delivery time have an impact on skewing?
The warp delivery length is much smaller than the backward movement of the weaving mouth during carding, and for warp knits with a stitch count of over 100, the warp delivery time has no impact on skewing.
7.Does the coiler time have an impact on skewing?
The coiler time has an impact on skewing; unreasonable coiler time can cause local running of the warp, creases, insufficient tension in local mesh, and an increase in carding force, making it easy to cause skewing.
8.Can equal tension weaving prevent skewing?
Equal tension weaving is beneficial in overcoming skewing, so flat knitting is often used to make the position of the warp position line overlap with the warp diameter, with a tolerance of 0 for mesh.
9.Why does hidden skewing often occur on the coiling roller?
As the imitation of the jacking shaft loom is very long, the backward movement of the weaving mouth during carding is quite large, and the mesh will be in a relaxed state, causing the tension value of the metal mesh on the coiling roller to appear negative during the moment of carding. In addition, the natural inclination of the skew mesh causes uneven elastic shrinkage on the skew mesh square hole mesh on the coiling roller, which destroys the original flatness of the mesh, and hidden skewing appears on the second or third layer of the mesh on the coiling roller.

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