In the actual production process of dry lamination, there are often failures due to mechanical reasons or other factors, such as: the generation of air bubbles, the low fastness of the composite product, the wrinkling and curling of the finished product, and the stretching or shrinking of the composite product. The curling and wrinkling of the composite product directly lead to the scrapping of the product. The analysis is related to the following points:
1. The occurrence of curling and wrinkling is related to the quality of its own material.
One end of the composite material or printing substrate is loose and the other end is tight, and there are deviations in thickness. If the tightness of the two ends of the film roll differs greatly, after the machine is put on, the film swings up and down, left and right, and it may cause wrinkles and curling, because the material When entering between the hot steel roller and the hot pressing rubber roller, it cannot be in a horizontal state with the hot pressing rubber roller, and cannot be pressed flatly, causing the composite product to be wrinkled and twill, resulting in product scrapping. When the composite material is PE or CPP, If the thickness deviation exceeds 10%, it is also very easy to wrinkle. At this time, the tension of the composite material can be appropriately increased, and it can be squeezed horizontally with the hot-pressing rubber roller as much as possible, but it should be noted that the tension should be moderate. , If the tension is too high, the composite material will be elongated, causing the bag mouth to curl inward. If the deviation of the composite material is too large, it can not be used. Due to the deviation of the thickness of the material itself, the product is wrinkled and curled, so the thickness must be carefully checked before the machine is used. When it exceeds 10%, it is best not to use it.
2. Wrinkling and curling are also caused by misoperation.
For example, the pressure of the hot glue roller is uneven, and the hot glue pressure roller rotates back and forth during operation, so that the composite material cannot be fed smoothly, resulting in wrinkling and curling. The solution is to withdraw the left and right nut wires of the hot glue roller, re-tighten it, and use even force. If the cylinder pressure valve locks the hot glue roller, then it should be carefully observed, and the speed should be slowed down to contact the hot steel. At the end of the roller, add the air valve pressure and finally squeeze it in parallel, and observe the pressure indicator number, so as to feed the material in parallel to reduce the probability of wrinkling and curling failure. In actual production, curling and wrinkling are also related to the temperature of the hot steel roll. If the temperature of the hot roll is too high, the probability of curling will also increase accordingly, especially in BOPP/CPP and BOPP/PE composite structures. If the temperature is too high, it will even cause the PE film to be adhered by the hot steel roll and firmly adhere to the steel roll, which not only wastes the material, but also delays the production efficiency. The treatment method is to stop the machine and turn off the temperature control of the hot steel roll. , and then treat after cooling down. In general, the temperature of the hot steel roll is adjusted according to the actual environment and operation effect, and also with the width and thickness of the structure. Good temperature control will definitely reduce the failure probability of curling and wrinkling.
3. The curling phenomenon has a lot to do with the tension control of the printing substrate and the composite.
Normal production requires the substrate to be flat and moderate for coating and gluing. The tension of the composite should match the tension of the substrate. If the tension of the substrate is too high (coated film) and the tension of the composite material is too small (composite film), the finished bag will roll outwards, causing the bag mouth to be uneven. If the tension of the printing substrate is too small and the tension of the composite material is too large, the finished bag will be rolled inward, resulting in poor opening of the packaging bag, the opening is bent inward, and the sealing is difficult. The solution is to adjust the printing substrate through the guide roller. Tension with composite materials. Adjusting the tension of the printing substrate or the composite material is usually done by a manual screw nut or by a magnetic powder brake.
4. The inappropriate winding tension of the composite product will also cause longitudinal and transverse wrinkles.
If the tension of the rewinding composite product is too small, with the gradual increase of the rewinding material, horizontal twill lines will appear at the bottom, causing the finished bag to be uneven and affecting the appearance. Due to the effect of tension, the finished product will appear longitudinal wrinkles, especially in the early stage of the machine. Of course, the paper tube is not smooth, and the winding is high and low. The solution is: the speed must be from slow to fast when starting, the purpose is to slow down the pulling force and reduce the probability of wrinkling, the tension should be moderate, try to make the starting winding without wrinkles and not too loose, and the winding tension should be reduced after the standby speed is normal. Constant, you can reduce the chance of wrinkling, usually, the winding power is flattened by a spring pressure piece or a magnetic powder brake.
5. The failure of curling and wrinkling is also related to the uneven gluing.
When gluing the substrate, if there is more glue on one side and less glue on the other side, the side with more glue will inevitably bend inward after drying, and even sticking will occur. If the gluing system of the laminating machine determines the thickness of the gluing roller, the left and right nut bars should be adjusted to make the gluing even; or adjust later. The best way to test whether the gluing is uniform is to press the gluing system with the left and right index fingers to observe its thickness, and finally make the gluing evenly, which will effectively reduce the phenomenon of curling and wrinkling.
6. Curling, wrinkling and compounding are related to the cleanliness of the traction rollers of each guide roller.
During the operation of the substrate, if the traction roller is dirty or the surface is uneven, it will easily lead to oblique wrinkles. The best way at this time is to use newspaper to cut 10cm long and 6cm wide for shimming. Due to inertia, the newspaper will synchronize with the traction roller. Rotate, so that the twill phenomenon can be solved.
7. Mechanical failure is related to wrinkling after compounding.
The mechanical failure of the dry laminator causes the tension of the substrate to be uncontrollable, either too large or too small to be smoothly fed into the hot steel roll, which will cause wrinkles and curling at the winding part. After careful analysis, the conclusion There are two points. Then the magnetic powder brake is out of balance and the tension is large and small, which cannot be controlled. Either the sensitivity of the sensor is distorted, and the speeds of the front and rear motors are not coordinated, which causes the above phenomenon. Finally, it is found that the sensor is distorted. Model of the sensor, the tension is controlled, and the fault is eliminated.
The reasons for composite wrinkling are generally: 1) The initial adhesion of the adhesive itself is insufficient; 2) The solvent residue is high; 3) The amount of glue applied is too high or low; 4) The tension of the composite substrate does not match; 5) The air volume of the oven is too large; 6 ) The winding tension is too small; 7) The flatness of the substrate is not good. The wrinkling in winding is mainly due to the poor control of tension in the composite winding process. After winding, the outside is tight and the inside is loose, and the gap between the layers is large, providing space for shrinkage.
