What are the causes of wrong pattern and disorderly pattern on computer jacquard knitting machine?
If we don't consider the special situation brought by the special tissue and only consider the wrong and disorderly stitching caused by incorrect stitching, there are mainly the following possibilities:
a. The poor synchronization between the needle selector and the circular machine itself will lead to the disorder of the whole disc. At this time, the parameters of the machine can be readjusted.
b. If the depth of the jacquard piece pressed by the needle selector is not enough, it will lead to horizontal random pattern. If the middle needle is not pressed down enough, the middle needle will still be lifted up by the lifter triangle for weaving. At this time, the pattern of the specific number of ways will be disordered, and the disordered pattern will be transverse.
c. The abnormal wear of jacquard piece (both tappet piece and connecting pin have the same phenomenon) will lead to vertical random pattern.
d. Loom assembly design problems, leading to the overall pattern disorder, this problem is relatively rare.
e. The design or processing problems of reset triangle or tappet three track lead to the random number of specific paths. It will appear when the triangle is worn or there are problems in the assembly design.
f. The needle selection point (the position where the needle selector presses the jacquard piece into the deepest part of the needle barrel) is too close to the lifter triangle, which leads to random pattern. The middle needle has already entered into the lifter triangle track before finishing the needle selection action (pressed by the jacquard piece), which leads to random pattern, usually the whole plate of horizontal random pattern.
g. The assembly position of the needle selector and the heel of the jacquard piece is poor, which leads to random pattern. For example, the needle selector should not press the jacquard when the knife head is raised, but because the installation position of the needle selector is too low, the jacquard is pressed, resulting in a certain number of random patterns.
Analysis of common defects and causes of the most complete knitted fabric in history
1. Missing needle:
In the knitting process, the needle does not hook to the wool yarn, or after hook to the wool yarn, it comes out of the needle hook and forms the coil detachments, resulting in vertical streaks and small holes on the cloth surface.
Causes and treatment methods:
(1) The causes of the needle include bad needle hook or needle tongue, different length of needle tongue and different size of needle head（ (needle change)
(2) Yarn mouth position is not good, too high or too low from the needle tongue, too inside or outside（ Yarn adjusting nozzle)
(3) The needle groove is not clean or has foreign matter, the needle groove is too loose or too tight, resulting in the needle can not work normally（ Cleaning and repairing needle slot)
(4) The relative position of the triangle of the sinker is not correct, and the needle passes through the old coil when the loop is withdrawn（ Adjust the relative position of settlement triangle and needle triangle)
(5) The feeding tension is too small or too hard（ Adjust the yarn delivery or bending depth, yarn re waxing) uneven or too loose winding tension（ The double-sided fabric is also divided into inner leakage needle and outer leakage needle. The needle leakage on the needle disc is inner leakage needle, and the needle leakage on the needle barrel is outer leakage needle.
2. Broken needle:
A vertical pit or more continuous hole.
reason:
(1) The reason for knitting needles is that the needles are too old, the hooks and tongues are damaged, or the wrong needles are used（ (needle change)
(2) The slot of the pin is tight and the movement of the needle is difficult（ Repair needle slot)
(3) Yarn count problem, roving, large yarn knot or disordered yarn stuck needle hook, etc.
(4) The cloth frame is too tight, and the cloth tension is too high（ Adjust the winding tension)
(5) The position of yarn mouth is not good（ Position of Spinner
3. Impact pin:
In the knitting process, the phenomenon of collision between the heel and triangle group will damage the needle barrel (needle disc), needles, etc., and the loss of the impact needle is huge, so it should be carefully avoided in production.
reason:
(1) Lack of fuel, too high speed;
(2) The upper and lower needle slots are not aligned, the needle door is not closed tightly, and the screws are loose;
(3) The needle groove is damaged, the edges and corners are fluffy, or there are broken stitches in the needle groove;
(4) The position of the yarn nozzle is wrong, or the cloth probe goes into the needle slot and fails;
(5) The yarn tension increases suddenly;
(6) The seam between the edges and corners is too large, the aisle is too narrow or the position of the upper and lower edges and corners is not well aligned, and the upper and lower needles collide;
(7) The cloth did not stop automatically when it was taken off. The cloth floated up, causing the impact pin.
4. Flower needle:
In the loop forming process, the new and old loops overlap to form a loop, and continuous or discontinuous pits and yarn disorder appear on the cloth surface. The looping is mainly caused by insufficient loop withdrawal or insufficient loop shedding (Baotou) of individual needles in the loop forming process.
reason:
(1) The reason of the needle: the needle tongue is crooked, the length is different, the needle is hairy, etc;
(2) The edge angle position is not good, and the pressing needle is insufficient;
(3) Needles too loose, defect, etc
(4) The fabric pulling force is too small and the loop is not enough;
(5) The yarn is uneven and the roving can't come out; Another: needle damage caused by the formation of flower needle called straight flower needle, irregular flower needle called loose flower needle.
5. Needle route:
The loop formed by some needles on the fabric is too large or too small, the obvious stripe appears in the longitudinal direction, and a thin mark appears when the cloth is pulled or illuminated.
reason:
(1) The size and length of the needle are different, and the front and back of the needle are skewed;
(2) Due to the blockage of the needle slot by the dirt, the needle slot is tight or the width of the needle slot is different, and the oil is polluted (cleaning the needle slot and changing the needle);
(3) There are many reasons, such as abrasion of the sinker or flying flowers in the slot;
(4) There is no obvious difference between the needle path and the leaf path on the cloth surface when using the wrong needle, but the leaf path is generally several continuous because the leaves are more easily affected by each other than the needles.
6. Oil needle:
One or more of the longitudinal lines of the fabric with oil stains appear as a straight black line on the cloth surface.
reason:
(1) The oil in the oil pipeline overflows or the amount of oil added is too much or too little due to careless refueling;
(2) After cleaning the loom, too much residual oil is left in the loom;
(3) The needles are not clean and stained with oil;
(4) The groove of the needle is tight and the friction causes oil stain.
7. Horizontal pattern:
In the fabric, there are regular horizontal coils, which are less dense and uneven than other horizontal coils. There are bright and dark horizontal bars on the fabric surface. According to the different causes, they are subdivided into the following defects.
(1) Roving:
a. The yarn is too thick or too fine, such as regular wrong yarn or irregular yarn evenness;
b. When two yarns are wound or two yarns are woven, one yarn is broken (such as broken frame).
(2) Elastic yarn:
a. The yarn tension is too loose or too tight（ Check whether the yarn channel is abnormal;
b. Check whether the yarn tension is consistent（ Adjust the bending depth, concentricity and levelness of the needle pressing triangle.
8. Broken yarn:
Some yarn ends are broken during weaving.
reason:
a. Poor yarn quality, poor strength, or large yarn knot, large yarn wool can not pass through;
b. The position of the yarn mouth is not good, and the yarn fed is located at the scissors of the knitting needle;
c. The bobbin is not well formed and the yarn ends are broken when unwinding;
d. The conveyor arm is not open;
e. The needle drawing at the section is not good;
f. The needle slot is dirty, making it difficult for the needle to fall.
9. Wrong flowers:
The pattern on the cloth does not match the customer's requirement.
reason:
a. Wrong computer program; Or computer reset error (easy to occur when shutdown or restart)
b. The fingers are damaged during knitting;
c. When the operator changes the yarn, he changes the wrong yarn or connects the wrong finger.
10. Holes:
There are small or large holes on the cloth surface, which are formed on the cloth surface due to the coil breaking.
reason:
a. Too low yarn strength, bad yarn, too hard yarn, etc（ Change yarn or re wax)
b. Too much or too little yarn bending, bad alignment of edges and corners, yarn pad at scissors mouth, tight needle slot and bad position of yarn mouth when pressing needle;
c. The channel through which the yarn passes is abnormal, such as the conveyor pulley is broken, the belt is too tight and loose, or the thread jumps out of the yarn mouth and surrounds the yarn hook, or the yarn wool is blocked, etc;
d. Bad needles, such as crooked needles, bad needle tongue, not closed, needle tongue deviation and so on.
11. Yarn knot:
a. The knot of yarn itself is too big, such as the raw material is not good or the yarn is not turned over well, the knot is not cut;
b. The tension of the yarn is too small or the ring is loose.
12. Cloth removal:
Due to the failure, the knitting process can not be carried out continuously, resulting in the phenomenon of cloth detaching. Any cause that has an impact on the knitting may cause cloth detaching.
reason:
a. Around the conveyor wheel, such as loose ring, not covered, open, bad conveyor wheel;
b. The yarn is too oily, too hairy and too hard; Or turn over the yarn is not good, yarn hairiness;
c. The machine is not clean and the yarn mouth is blocked by flying hair;
d. Finger scissors are not good;
e. The air suction is blocked or the air pressure is low;
f. Bad needle.
13. Flying flowers:
The colored yarn wool flies from the yarn to the air or other colored yarn on the machine, weaves into the coil, and randomly distributes on the cloth surface.
reason:
a. When the operator blows the machine, the flying flowers may be woven into the cloth;
b. Flying flowers floating around are attached to the yarn and woven into the cloth;
c. When a large yarn knot passes through the yarn guide (nozzle), if there are flying flowers in the nozzle, the knot will bring it into the cloth;
d. There is no color separation during winding and spinning.
14. Tight frame, flying frame and broken frame:
a. Tight drawing frame is due to the poor channel of the drawing wheel or the conveying wheel, which causes the tension of the drawing frame to be tight and forms tight yarn like cross grain on the cloth surface;
b. The reason for the flying frame is that the feeding of the frame is not good, the needle hook is difficult to hook to the wire of the frame, the frame can not be woven in, the fabric surface is bubbly, and the fabric bottom is shallow.
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