[technique] fabric appearance defects and its causes analysis

Mainly oil, oil, weft, oil, oil, water stains, friction marks, holes, creases, uneven fluff, hair removal, ripples.

(1) Oil

Appearance: A single piece of warp yarn in the fabric is contaminated with grease and the like.

Causes: Before the weft yarns are weaving, winding, or picking, they are impregnated with mechanical lubricants.

(2) Oil weft

Appearance: In the fabric, a single piece of weft yarn is contaminated with grease and the like.

Causes: When the weft yarn is weaving, it is impregnated with mechanical lubricants when it is shaken, wound up, or picked up.

(3) Oil yarn

Appearance: The yarn in the knitted fabric is contaminated with grease and other parts.

Cause: Contaminated with grease, etc. during winding or during transportation.

(4) Oil pollution

Appearance: Embroidered cloth or finished cloth, with oily stains ranging from roll to sheet.

Causes: a. In the course of weaving or dyeing and finishing, splashed into lubricants. b. Contamination of oils and fats during transportation.

(5) water stains

Appearance: The surface of the cloth or the finished cloth has traces that are naturally dried after being impregnated with water.

Causes: a. Embroidered cloth or finished cloth, impregnated with water. b. Oil traces on the embroidered cloth, oil latitude, or oil stains on the embroidered cloth and the finished cloth, which remain after washing.

(6) Chafe Mark

Appearance: In the process of processing, the fabric is visibly different in gloss, hue, and texture due to the friction of the fabric.

Causes: a. In the process of processing, the fabric was transported and placed under unexpected friction. b. Staining occurs between the elliptical wheel and the fabric when dyeing with the Wenqi machine. c. In the machine of each process, it is subject to rough surface friction.

(7) Holes

Appearance: The cloth surface of the embroidered cloth or the finished fabric, and the warp and weft yarns are cut off to form a broken hole.

Causes: During the delivery or storage period, a sharp object collided. Hand-fishing is used when manpower is moved.

(8) crease

Appearance: There is a trace of folding on the cloth surface, and the groove is uneven and uneven. It is wide and not a thin line. The tension is flat and disappears, often in the direction of the length of the cloth and the beginning and end of a cloth.

Causes: a, when the fabric is folded into a sheet, the fabric is uneven. Packed by the hydraulic press, the applied pressure is too large. b. Wrinkles are present at the front joints of the pre-treatment projects. c. When the pre-treatment process was introduced into the cloth, the cloth feeder did not fully develop the fabric, and the fabric was subjected to excessive force during cloth feeding. d. In the pre-treatment process, the cloth guide rollers in the machine wash tank are not parallel or bent. e. In the pre-treatment project, the machine bends the open cloth roll before the press roll, the adjustment angle is too large or too small, and the peripheral surface of the curved cloth roll is worn, and the cloth does not fully spread flatly before entering the press roll. f. When using a rotary cylinder dryer fabric, the fabric is creased and wrapped around the cylinder. g. When the fabric is wide or shaped, the created creases are not leveled.

(9) Raising unevenness

Appearance: Raised fabrics, corduroy, velvet, towels, etc. The raised fabrics have a non-uniform appearance due to the length of the tufts or loops.

Causes: a. The fabric has wrinkles when it is pulled, or the fabric is not evenly tensioned. b. The corduroy and velvet shearing are not controlled evenly. c. When the towels are woven, the hair loops formed are of different sizes.

(10) Hair Removal

Appearance: The hair tufts of the shearing fabric are easy to pull off.

Causes: The improper organization of the fabric, after cutting into a tuft of yarn, the clamping force is too small.

(11) Ripple

Appearance: There are a large number of yarns in the fabric, the movement does not occur in situ, and the fabric produces uneven wave bending. The warp yarns are far smaller than the weft yarns, or the warp yarns are filamentous fibers, and the weft yarns are most likely to be spun.

Causes: a. When dyeing with the Wenqi dyeing machine, the bath ratio is too small and the length of the input fabric is excessive. The elliptical wheel rotates too fast. The fabric knots are subjected to abnormal tension. b. When dyeing with a liquid dyeing machine, the bath ratio is small for a large amount of cloth. Spray jets are too strong. c. The cloth guide and opening used for continuous production of open width.

3 fabric appearance control point analysis

As a textile manufacturer, it may be more important to control fabric defects caused by the first two major reasons, namely the defects in Sections 2.1 and 2.2. Next, we focus on the analysis of fabric defects that are often difficult to control but which are often difficult to control in the weaving process.

Wet point

Weft shrinkage is a kind of dense defect that the weft yarn twists into the cloth, or the loop appears on the cloth surface. When the weft yarn is knitted in, the original yarn itself or the machine mechanically has drawbacks, and it cannot be driven straight into the cloth mouth, thus causing many star-shaped kink or loop-like small flaws on the cloth surface.

The weft shrinkage point is common in high-count and high-density pure cotton fabrics (such as poplin, oblique card and satin, etc.). In the polyester-cotton blended fine cloth, poplin, khaki and other fabrics, it is the main weaving. On pure cotton high density poplin fabrics, the weft of the balloon is easily generated during the weaving due to the warp yarns of the warp yarns. In the polyester/cotton fabrics, the excellent performances of the Ting, Shuang, and Shuang as well as the disadvantages of preventing fuzzing and pilling after wearing are fully utilized for the factory. The twist configuration of the warp and weft yarns is generally larger than that of the special (branch) pure cotton yarns; Polyester fiber has good elasticity and strong yarn resistance. Therefore, when weaving, a slight relaxation of weft yarn will cause kink and weft.

The shape of the weft shrinkage point on the cloth surface can be roughly divided into four types: kink, weft, warp, weft, warp, warp, warp, warp, weft, warp, warp, weft, warp, warp, warp, warp, weft.

(1) Kink Weft

Most of them occur in the area about 250-300mm away from the side of the shuttle, and they are obviously small circles on the cloth surface, or the cloth surface, or weaving in the cloth. The length is about 6-25mm. Kink The weft shrinkage is mainly caused when the shuttle moves from the shuttle side toward the switch side into the shed.

(2) The warp has been shrinking

Generally distributed in the fabric on both sides of the site, such as the majority of poplin fabric from the cloth is 5 to 10cm. The warp yarns behind the 1-5 cm point of the weft point are usually attached with cotton, bamboo knots, knots, and hard blocks. The warp has been caused by the warp shrinkage, on-site observation and physical analysis, which are generated when the shuttle exits the shed.

In recent years, plain weave, poplin, and oblique cards have been used as fabrics. In order to reduce severance and squeaking, weaving machines are widely used in weaving machines. If the installation is poor, the tip of the needle is fluffed or slightly hooked, and the warp and weft of the warp needle path may be caused on the cloth surface. Its shape is the same as the weft shrinkage. However, it does not belong to the category of common shrinkage.

(3) One-dimensional square-shaped weft

Rectangular block weft on the poplin fabric occurs almost entirely on both sides of the cloth, and its width is generally 30 to 40 mm and length 20 to 30 mm. Although the distribution is dense, there are still intervals. A square-shaped weft shrinkage, after physical analysis, is generated when the shuttle exits the shed.

(4) Scattered Weft

The distribution of defects is irregular, and the width of the weft shrinking circle is small. The minimum is only 1mm ~ 2mm, not easy to find, often cause leakage test. When weaving high-density poplin fabrics on the 1511 automatic shuttle weaving machine, the only regularity of this defect on the cloth surface is: regardless of the right and left hand loom, when the opening step (F3) is positioned, the fastening screw is forward and the shuttle is in the right hand On one side, defects also appear on the same side.

The cause of shrinkage

(1) The quality of the original yarn

The yarn twist is too large, the free end retreats seriously, causing the weft to fly unstable and causing weft; the yarn hairiness is long, the knot end is large, and the weft yarn end is in a floating state. Once the weft hairiness is rubbed with the warp yarn, it is easy to form. Winding, causing weft.

(2) Semi-product quality

The quality of the weaving shaft is poor, and the opening is not clear due to sticking, twisting, and twisting, and weft yarn movement is hindered, especially weft-laden weft and other weft shrinkage.

(3) Mechanical status

Impurities in compressed air can easily cause blockages in the air path, which can make the air supply pressure unstable, and the weft yarns fly unevenly and form a weft. Air leakage caused by gas components such as gas pipes, joints, and regulating valves caused the air pressure to be unstable, affecting the normal flight of the weft.

(4) Unclear opening

Even very light yarn slacking and fiber-to-fiber adhesion can make the weft flight obstructed and create weft.

(5) Improper weft insertion process

Inappropriate yarn release needle release time, nozzle solenoid valve opening and closing time is not accurate, nozzle pressure is too high or too low, causing the weft to have a crowd after the flight, the weft yarn can not fly straight through the shed and cause weft; the right side of the winding side closure The time was late and the weft was not caught in time and the weft was retracted. Weft shrinkage due to unreasonable weft insertion time: the weft insertion is too early, the opening height is not enough, and the phenomenon of weft shrinkage due to the poor weft flight due to warp hairiness and other defects tends to occur; otherwise, the weft insertion is too late and the weft reaches The corner is late and the opening height is relatively small. The head end of the weft yarn collides with the warp yarn, causing the weft yarn to be hindered from forming the weft. In addition, the injection time is improperly matched. When the weft yarn reaches a certain point, the auxiliary nozzle electromagnetic valve at the place does not open in time, causing the weft to fly in a relaxed state and forming a weft.

(6) Low temperature and humidity in the workshop

The elasticity between the fibers is relatively enhanced and the friction is reduced, which promotes the increase of anti-torsional torque.

solution

Generally, we should choose the smaller twist factor as much as possible when weft strength meets the requirements of weaving. Polyester and cotton fabrics should improve the effect of twisting; design the best twist, reduce the unevenness; use knotless yarn; Properly postponed opening when not large.

The warp tension of the warp should be 2 to 3 g. Strictly control the sizing side row and correct the opening distance of the plate to ensure that the opening of the plate matches the width of the blank.

Impurity of compressed air can be installed in the air inlet double filter, the filter regularly cleaning and maintenance; cloth appears moisture should check whether the normal operation of the drying system; in daily maintenance, we must carefully use the ultrasonic vibration instrument to clean the solenoid valve .

In the initial stage of the machine, the heald frame and opening stroke must be adjusted according to the process requirements, and the consistency of the two sides of the heald frame must be taken into account when adjusting the heald frame. On the air-jet loom with open-slots, the steel wire rope is a flexible carrier that is easy to pull down. It is usually checked once a week for the height of the heald frame. This will not only eliminate the effect of the wire rope being stretched, but also eliminate the operation and repair machine. Workers and crews suffer from weft shrinkage due to unevenness in the heald frames or inaccurate height due to frequent machine operations, bad car repairs, and improper adjustments.

Ensure that the yarn guide channel is clear. Check the steel file for serious scars and bends.

The process design must be reasonable.

In order to solve the weft caused by the impeded jet, we must reasonably adjust the geometry of the front shed, increase the clarity of the opening, and appropriately increase the tension on the machine.

Properly extend the spray time of the last set of auxiliary nozzles, and appropriately advance the opening time of the right twisted edge device to timely hold the head end of the weft.

The temperature and humidity of the workshop is unstable, so that the performance of warp and weft yarns changes, affecting the clarity of the shed, and must be adjusted in time. The general air-jet looms have a temperature of 22 to 26°C and a relative humidity of 72% to 78%.