Analysis of the causes of unqualified knitted fabrics (referring to semi-finished products)
First, the defects caused by the spinning mill
1. Coarse yarn - the tension is not uniform during spinning, the twist is loose and tight, and the coarse yarn will cause the fabric to lie horizontally.
2, from the horizontal - spinning with cotton, mixed with different counts of different raw material yarn, or due to coarse yarn support.
3, the hair is large - especially the A yarn (combed), because the cotton fiber is short, after the dyeing process, it is easy to rub the hair or cause insufficient twist.
4, the blasting force is poor - the cotton fiber is too bad or the twist is too small after spinning into a yarn, the tearing tension of the cotton yarn after spinning is very poor.
5, dead cotton - the cotton is not mature enough, the quality is too bad (commonly known as malnourished cotton).
6, cotton crust - here mainly refers to the flower ash wash cloth, the flower gray yarn has a wash water with flower ash and bleachable flower ash. If the flower ash used for washing water is used, the material of the bleachable ash raw material is misused, and the cotton quilt can not be removed after washing at a temperature of 50-80 °C.
7. Loss is large - the raw material (with cotton) is too bad when spinning, and the proportion of impurities is large, which is caused by removing impurities after bleaching.
Second, the defects caused by the weaving factory
1, needle line (needle line)
The needle path refers to the continuous straight lines on the knitted fabric. There are four main reasons for the formation of the needle path:
a) bad needle
The bad needle includes all the changed needles or the abnormal opening and closing of the tongue, resulting in a deformation of the coil which is significantly different from the adjacent coil.
b) damaged needle pit
Damage to the needle pit means that the distance between the pit and the groove is uneven, and coils of different sizes or shapes are produced during weaving.
c) There is a foreign object in the needle
In some long-term woven fabrics of short fibers such as cotton, the short fibers of the short fibers tend to accumulate in the needle pits, so that the up and down process of the knitting needles is hindered, resulting in uneven yarn tension to form a needle path.
d) Oil needle road
It is mainly formed by an abnormal amount of lubricating oil. In theory, these oil needles are emulsified and dissolved by water during dyeing and washing, but there are exceptions, especially T/C cloth, so it is best to control the oil needle when the cloth is in the state of the cloth.
2, from the horizontal (Barriness)
The horizontal direction of the knitted fabric refers to the formation of latitudinal transverse stripes on the cloth surface, and these transverse stripes have many causes, and can generally be studied from both raw materials and mechanical aspects.
A, raw material
Cylindrical knitted fabric is a principle in which a plurality of yarns are woven into the machine at the same time and each of them is formed into a horizontal row on the cloth, and is repeated after several tens of lines, that is, the interlaced cloth. Therefore, when one or more of the shed yarns are different from the others, it is easy to have repetitive horizontal stripes on the cloth. This includes different counts due to mismatching, yarns of different raw materials, or due to coarse and uneven yarns themselves.
B, mechanical
The mechanical property is mainly due to the fact that one or more of the angular adjustments are different from the others, or the tension of one of the yam yarns is different, so that a row of coils of different shapes and upper and lower shapes are formed on the cloth body to erect. Mechanical traverse is the most common one in which one of the dies has forgotten to use the conveyor belt to draw yarn into the machine.
3, blasting holes (Holes)
A blasthole is a small hole that appears on a cloth because some of the weaker tension on the yarn is formed by the detachment of the needle during weaving.
4, yarn break (Yarn breakage)
Broken yarn refers to a large number of needles with a length of needle position on the cloth. This is due to the failure of the shutdown facility to stop the weaving machine in time.
5, Drop stitch
Leakage refers to the small hole caused by the failure of the knitting needle to pick up the yarn to be woven. It is often found in some fabrics with knitting or double gauze, so-called biting single yarn.
6, Broken needle (Broken needle)
The rotten needle is like the shape of the needle position, which is formed by the break of the needle hook.
7. Unwanted tuck stitch
A flower needle is an irregular needle-containing yarn loop that appears on the same straight line without arrangement. It is mainly caused by a problem with the tongue.
8, the center mark (Centre mark)
The occurrence of the nick is due to the excessive pressure of the cloth stick or the excessive tension of the cloth, which causes the edge of the cloth to be pressed into a dead mark by pressure. In severe cases, these nicks cannot be restored after they have been set. Polyester fabric is very easy to form the problem of creases, so the fabric should be loosened immediately after weaving.
9, horse mark (Dog mark)
Horseshoe marks are only found on rib machines and double-sided machines made in Hong Kong (referred to as Hong Kong). They are inevitable due to mechanical design. They usually disappear after reprocessing, but they cannot disappear if the school machine is improper.
10. Flying waste
Flying flowers refer to some foreign fibers that are not fabrics themselves. They are mainly colored fibers that are attached to the yarn during the weaving process and brought into the fabric. These fibers are not only mixed into the normal fibers when spinning, but are mainly caused by the other yarns when the yarn is turned or woven, or the fibers that are flying off by themselves are accumulated in some old yarn positions. Commonly known as "hairy", strengthening the humidity in the workshop and improving the hair dryer system will help control the flying flowers.
Third, the defects caused by the dyeing factory
1, color flower - mainly due to improper selection of dye combination, the machine is not smooth (nozzle blocked), water flow, improper cloth speed cycle or excessive dyeing, blanking too fast and other reasons.
2, yin and yang - water pressure adjustment is too small, the dyeing liquid concentration is not uniform when the material is cut, the auxiliaries are fast; or the dye combination is not appropriate.
3, color stains - caused by the following reasons:
(1) The hardness of water or additives is too large (ie, the content of NaC1, Na2SO4, Na2CO3 exceeds the standard);
(2) The dye itself has low solubility;
(3) formed by a readily hydrolyzable dye;
(4) The water pressure is too large to cause foam.
4, floating color - post-processing time is not enough or the temperature is not high enough, the washing is not clean. Floating colors are sometimes like cloud-like flowers.
5, cloud-like flowers (referring to the unburnable) - the machine is not smooth, after the shutdown, the cloth head is not immediately processed, water and chaos cloth and other reasons.
6, the difference (mainly the difference) -
(1) The amount of cloth loaded between each tube is too different;
(2) The water jet pressure between the tube and the tube is inconsistent or the individual nozzles are slightly blocked.
7, the hair is large - (1) the water is adjusted too large, the cycle is too short; (2) the dyeing time is too long.
8, the blasting power is poor - stripped color, or excessive hydrogen peroxide, sodium hydroxide, etc., causing strict damage to the fiber.
9. Explosion - Sodium hydroxide, hydrogen peroxide, etc. are drawn into the cylinder without dilution.
10, hook-and-rug cloth - there is a problem in the inner wall of the dyeing tank (most commonly Lily) or the car used to load the cloth.
11, stains - cylinder, car, dehydrator, etc. are not clean.
12, fly material - the dye is not dissolved into the workshop, the wind is blown onto the cloth surface to cause flying material stains.
13. Weathering (coloring) - Dyes that are susceptible to weathering (especially dyed emerald green) are susceptible to wind and light when wet cloth.
14, creases (including dead marks) - there are many kinds of creases:
A. The main formation in the cylinder is that the cooling time is too fast, and the nozzle adjustment and the lifting drum speed are not properly matched;
B, the fabric is very tight and dense;
C. The dehydrator is loaded with too much cloth, and it is still hard to fit after being filled; the dehydration time is too long;
D. The drying machine is too long to dry and not to solve the cloth;
15, lip print - wet cloth pressed in the barrel machine for too long;
16, twill color marks - the cloth is too twisted when the barrel is dry, not properly turned;
17. Dry and wet printing - caused by improper feeding of the flat-width machine;
18. Flat machine marks—symmetric marks caused by high temperature when the cylinder cloth is dry on the flat machine;
19, the fan cloth machine scratches - the wet fan machine frame is too wide, caused by the scratch of the collar.
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