Reasons, countermeasures and effects of BOPP film slitting quality ---
ten. Color circle
The color circle is caused by a certain degree of contamination inside or outside the film, which causes the quality of the color circle on the end face of the film roll after slitting and winding. Membrane surface pollution sources come from two aspects. One is the film-forming process. The color circles generated in the front part of the film, such as raw materials, feeding systems, extrusion systems, and die flow channels, generally cause pollution to the inside of the film (core layer). Some color-circle products can clearly observe a large amount of fish-eye impurities in the film. The color circles generated in the film-forming stage and the slitting process mainly cause pollution to the outside (surface) of the film, but whether it is internal or external pollution, It is impossible to remove the impurities from the contaminated film and restore the original appearance. The product with serious color circle has low transparency, the film color is different from the normal product, and it can not be used at all. It can only be reduced to other external treatments, while the products with slight color circles are It has little effect on the transparency of the product and does not affect the use effect of the single film. However, due to the inconspicuous appearance of the color circle product, the “selling phase” is poor, which has a great influence on the image of the German brand. It is not suitable for direct delivery. Secondary processing. If the color circle is caused by external dust pollution factors, the dust will be adsorbed on the surface of the film, resulting in poor quality of heat sealing and poor laser compression.
The basic knowledge of the slitting machine and its development process --
Basic knowledge and development of slitting machine
In the process of slitting, the stable tension system is an important indicator to ensure the quality of the product. It controls the mutual tension between unwinding, drawing, slitting, winding, etc., so that the slitting material is always in the cutting process. A steady state. If the tension is properly controlled, it can avoid the deformation and drift of the raw materials during the process of speeding up and slowing down the machine. Generally, the unwinding tension is slightly larger than the sum of the reel tensions. Most of the previous slitting machines use magnetic powder clutch to control the tension, but the magnetic powder clutch speed can not be high. It is easy to cause high-speed friction of the magnetic powder during operation, which causes high temperature and shortens its life. In severe cases, it will be stuck and the machine operation will be blocked. With the development of science and technology, the use of servo drive technology, most of them now use vector variable frequency motor to control the tension system of the slitting machine. The automatic detection of the pendulum roller makes the man-machine interface intuitive, the tension system is more stable and reliable, and easy to operate.
Slitting machine parts ---
2. Attenuation and tension compensation of the tension of the rewinding and unwinding: It is generally believed that maintaining the constant tension of the aluminum foil during the rewinding and unwinding of the aluminum foil is beneficial to the apparent quality of the finished aluminum foil, but it is not. The best method is to increase the tension of the aluminum foil according to a certain rule as the diameter of the coil increases, and the smaller the diameter, the lower the tension value. There are automatic tension control and manual tension control during the slitting operation. The automatic tension control system is the leading set tension attenuation value, which is maintained throughout the winding process. The manual tension control requires the operator to continuously adjust the diameter of the master roll to meet the tension required for the aluminum foil during operation. When setting the automatic tension operation, set the initial tension before setting the tension attenuation value. Taking the setting of the slitting and unwinding attenuation value as an example, the setting principle is that the aluminum foil tension attenuation value (%) is equal to the tension at the end of winding of the aluminum foil minus the initial tension and then divided by the initial tension. Multiply by 100%. When setting the automatic tension value of the unwinding, it should not be too large, otherwise the aluminum foil winding surface has a large hardness and is prone to warping. But the tension should not be too small, too small and easy to cause the rewinding body to be too loose, and the winding is not neatly running. Therefore, the quality of the rewinding and unwinding during the aluminum foil slitting operation is mainly affected by the change of the tension of the aluminum foil. It can be seen that the mastery of the retracting and unwinding control system is the key to affecting the quality.
3. The change of speed during slitting affects the change of tension: When the speed is increased or decelerated, the speed of the main motor changes. Firstly, it causes the instantaneous change of the tension of the unwinding traction to the winding section of the aluminum foil, and it is necessary to slightly vibrate the aluminum foil after a period of time to gradually stabilize the tension. The instability of this tension is manifested in the fact that the finished roll is not well-wound, and the end face has unevenness, which affects the quality of the product.
Zhengzhou EAST IMPORT AND EXPORT co., ltd . ( a goulian group of company) a manufacturer and exporter for all kind of packaging machinery , like bopp tape coating machines, bopp tape slitting machines. Bopp tape core cutter, bopp tape core loader etc