What Are The Reasons For The Sealing Machine To Not Seal Firmly?

Map Tray Sealing Machine Loose seal is one of the common failures of continuous sealing machines. Loose seal has three meanings: ① The seal of the packaging bag cannot be sealed ② Under the pressure of the sealing knife, the bag mouth is sealed, but if it is pressed or peeled with a little force, the seal will break again; ③ When the sealed part is peeled off, half of the seal is firm and half is separated. The sealing quality of this packaging bag is still unqualified because the contents are easy to leak after squeezing during storage and transportation. This often happens when the composite lining is OPP or blown PE.

The first type of failure is mainly caused by the following reasons. Insufficient heat sealing temperature Generally, when the total thickness of the composite bag with OPP as the lining is 80-90μ, the heat sealing temperature should reach 170-180℃; when the total thickness of the composite bag with polyethylene as the lining is 85-100μ, the temperature should be controlled at 180-200℃. As long as the total thickness of the bag increases, the heat sealing temperature must be increased accordingly. Heat sealing speed is too fast: The failure of the sealing mouth is also related to the speed of the sealing machine. If the speed is too fast, the seal will be transported to the cold press by the traction roller for cooling before heating, and naturally it cannot meet the quality requirements of heat sealing. Improper pressure of cold press rubber wheel There is a cold press rubber wheel at the top and bottom. The pressure between them should be moderate. When adjusting the pressure, only clamp the spring.

Defective quality of heat sealing film: Sealing failure is also related to the quality of heat sealing film. If the corona treatment of the composite lining is uneven, the effect is not good, and it is exactly at the sealing point, it is absolutely impossible to seal. This situation is very rare, but once it happens, the product will inevitably be scrapped. Therefore, in the color printing and packaging industry, the next process is to supervise the previous process. Once a quality problem is found, the cause must be analyzed and solved in time.

If there is moisture and dirt at the sealing point, it will also cause unstable sealing. In short, in order to solve the problem of poor sealing in the first place, the heat sealing temperature can usually be appropriately increased, and then the heat sealing speed can be reduced, and the pressure of the cold press rubber wheel can be increased. The main reasons for the failure of the second type of sealing are as follows. Insufficient heat sealing temperature can solve the problem by appropriately increasing the heat sealing temperature.

The cutting surface of the heat sealing blade is not flat enough: The heat sealing blade is divided into two parts, the upper and lower parts. Usually, a thermocouple is installed in it to sense the temperature transfer. There are three screws on the heat sealing blade. The middle screw is used to support and reinforce the blade. The other two screws are equipped with pressure springs and gaskets, which are mainly used to adjust the pressure of the heat sealing blade. The upper blade and the lower blade have two springs respectively. The main reason for the uneven surface of the heat sealing blade is that the middle screw is installed obliquely instead of horizontally; or the pressure of the pressure spring of the upper heat sealing blade is uneven.