1,Aluminum Foil Vacuum BagColor is not allowed
Cause: mainly gravure drum diameter deviation, due to the layout is not correct, resulting in the deformation of the text, the shaft teeth spacing is uneven, the gap is large or small, or there is a top tooth phenomenon caused by overprinter is not allowed; thin film open reel tension control uneven or gravure film thickness uneven, lotus leaf edge , printing plate drum and imprint drum at both ends of the pressure is not uniform or multi-color overprinter when the pressure between the printing plate is inconsistent.
Gravure printing Overprinter is not the main quality problems, there are many reasons. Practical experience is mainly the reason for mechanical equipment, because machinery and equipment in the long-term survival of the operation, usually do not pay attention to maintenance, resulting in mechanical structural parts wear or obstacles, will cause overprinter is not allowed. This requires regular inspection and adjustment of the equipment, control of the plate-making process, the version of the error to a minimum, the selection of qualified film raw materials, timely elimination of other printing accidents caused by overprinter is not allowed.
2, aluminum foil bag heat seal strength is poor
1) The influence of aluminum foil bag heat sealing material
The types of heat sealing materials are different, the heat sealing strength is different, such as PP, PE/EVA heat seal strength is not consistent, the same film different polymerization methods of products, heat sealing strength is different, the thickness of the material, uniformity and so on will also affect the heat sealing strength, heat sealing layer different processing methods, such as blow molding, flow film, etc. The preservation time of the film is too long, the precipitate increases, the heat seal strength is poor after corona treatment, the moisture absorption material absorbs tide, the hot cover delamination, the stripping strength decreases.
2)Aluminum Foil Vacuum BagInfluence of composite membrane processing technology
Printing ink temperature resistance is poor or in the ink additives are not appropriate, in the bag high temperature, the printing layer occurs delamination, heat seal strength decreased. The heat sealing edge should be designed as no pattern as possible. Adhesive selection is also very important in the composite process, the ratio of adhesives, viscosity and other parameters are reasonable or not will affect the sealing strength. In the extrusion composite or coating process, the processing temperature is high, the material surface oxidation degree is large, is not conducive to heat seal.
3) The influence of bag making process
After hot seal, the sealing edge cooling is not enough, the training is insufficient, can not eliminate the internal stress, affects the strength and appearance, should be checked in time, strengthen the cooling water circulation system. The more heat seal times, the higher the heat seal strength. The number of longitudinal heat seals depends on the ratio of the effective length of the longitudinal welding knife to the length of the bag, and the number of transverse heat seals is determined by the combination number of the transverse heat sealing device of the machine. Good heat sealing requires a heat seal of at least two times.
