Cotton knitted fabric is undergoing scouring, bleaching and printing and dyeing wet processing Even if loose or low-tension equipment is used as much as possible, it will inevitably be stretched due to a certain tension, making the door width smaller, and at the same time, the thread will be skewed during processing. Although it has been through overfeeding wet expansion and overfeeding drying, its width and flatness have not yet met the requirements. Especially after being dried with a rotary screen, the fabric surface will show numerous wrinkles, the yarn will be more bent, and the undulations will increase. , causing the cloth surface to be uneven and unable to show good luster. In addition, there is fluff on the surface of the fabric, which makes the surface not smooth and the reflected light diffuses in all directions at different angles, so the luster is darker.
Calendering finishing of cotton fabric
In order to make the surface of cotton knitted fabrics smooth and smooth, feel soft and elastic, make the width of the fabric meet the specified requirements, correct the skewness of the threads, reduce the shrinkage, and improve the quality of cotton knitted fabrics, especially single-sided fabrics. Glossy, needs to be calendered.
Gloss requirements Higher cotton knitted fabrics can be electro-optically finished. Calendering finishing uses cotton fiber to have certain plasticity under hot and humid conditions and passes mechanical requirements.
Cotton knitted fabric The process of calendering using an overfeed calender is generally as follows: After drying, the fabrics are placed in a pile, turned over, seamed and spliced, calendered (expanded, steamed to wet, hot rolled, cooled, and dropped). Among them, the cloth speed It is 14m/min, the steam box temperature is 98-100℃, and the roller pressure is 3.8×104-19.8×104pa.
Electro-optical finishing is Using the effects of mechanical pressure, temperature, etc., the fabric has a smooth surface or fine parallel lines and good luster.
Electro-optical finishing is general It is carried out in cross-section. The finishing principle and processing process are basically similar to calendering finishing. The main difference is that electro-optical finishing not only smoothes the knitted fabric, but also rolls out parallel lines on the surface of the fabric, covering up the fibers or yarns on the surface of the fabric. The irregular arrangement of threads produces regular reflections of light, resulting in a strong luster and silky feel.
Electro-optical finishing machine Its structure and working principle are similar to those of a calender. The electro-optical machine mostly consists of two rollers, one hard and one soft. The hard roller can not only be heated, but also, under the action of gauge pressure, flatten the yarns on the surface of the knitted fabric, suppress the erected fluff, and change the surface of the fabric. It is smooth and smooth, and the degree of diffuse reflection of light is reduced, thereby improving the gloss of the fabric. In addition, before calendering, the knitted fabric is first reasonably expanded by the expansion support plate, so that the door width is increased and the longitudinal length is shortened. This state will be stabilized after calendering. Therefore, calendering has the functions of smoothing the surface of knitted fabrics, stabilizing the width, reducing shrinkage and producing luster.
Common qualities among them Summary of issues.
Longitudinal strands are skewed
1. Reasons
① When the fabric is calendered on three rollers, the number of windings is insufficient or too much and the winding direction is wrong.
②Input cloth At this time, the cloth head is crooked.
③Three rollers Calender, the pressure of the calender roller is uneven.
④Three rollers Calender, prevent improper burring (too slanted or too straight).
① felt blanket , When damping calendering, the seam head is not straight.
⑥Blanket The tension at both ends is different, and the gap between the knife and the damping roller is different at both ends during damping calendering.
2. Prevention Measures
① Check Later, make corrections.
1. Cause
①The feeding cloth is uneven.
②The tension is unevenly adjusted.
③The surface of the fiber drum of the three-roll calender is uneven.
2. Preventive measures
① Check in Whether the cloth is flat.
②Adjust the tension frame to make the tension on the edge of the cloth uniform.
③Reinforcement fiber roller maintenance.
Yin Yang
1. Reason
① The temperature of the rollers on the three-roll calender is too high; the temperature difference between the two rollers is large.
②Three rollers During the first and second calendering passes, the gray fabric is in contact with the roller on one side.
2. Prevention Measures
①Timely Check and adjust the temperature of the drum of the three-roll calender; adjust the temperature of the drum of the damping preshrinking machine and felt finishing machine to prevent automatic adjustment failure.
②Enhanced operation , and make corrections promptly.
Small breaks after calendering hole
1. Cause
① The angle of the burr of the three-roller calender is too oblique, the needle tip of the burr is lodging, and the burr is installed backwards.
②On fabric Regular holes occur due to loose screws on the support plate or other debris embedded in the fiber roller.
① Three rollers The adjusting screw on the calender support plate is resting on the steel rod of the support plate
Figure 3 three-roller calender
2. Preventive measures
① Correct the placement angle and height of the thorn nest, correct the lodging needle tip, and check when installing the thorn nest.
Check when ② The fiber roller and the rolled out gray cloth are used to remove debris in time.
③support plate After adjusting the amplitude, inspection should be strengthened to ensure that the textile screws are in contact with the steel roller.
Water damage
1. Generate Reason
①Steam The water accumulated in the box tube was not removed and sprayed on the gray cloth, causing the steam box to become too wet.
② Season Steam The box was not insulated, causing condensation to drip on the cloth.
2. Prevention Measures
①Power on Before cleaning, first remove the accumulated water in the pipeline, and the moisture supply to the steam box is strictly controlled in accordance with the process requirements.
②Create steam It is best for the box to have an interlayer and a waterproof ditch to prevent water from dripping on the cloth.
Stains
1. Cause
①Steam box , floors and other poor cleaning work.
② Calendering The rollers, damping rollers and blankets are stained with oily clothes, etc., causing fabric stains.
2. Prevention Measures
① Strengthen Cleaning of machines, steam boxes and floors.
② Strengthen the machine Clean the table, felts, damping rollers, knife rests, etc., and check the rolled fabrics at the same time, and remove oil stains and other dirt in a timely manner.
etter-spacing: 1px;”>② It is best to make a steam box with an interlayer and a waterproof ditch to prevent water from dripping on the cloth.
Stain
1. Reason
① Poor cleaning of steam tanks, floors, etc.
② The calendering roller, damping roller and felt are stained with oily clothes, etc., causing the fabric to Stained.
2. Preventive measures
① Strengthen the cleaning of machines, steam boxes and floors.
② Strengthen the cleaning work of the machine, felts, damping rollers, tool holders, etc., and at the same time check the rolled fabrics, and remove oil stains and other dirt in a timely manner.
