The reason:

(1) the heat sealing temperature is high, the film receives too much heat, and the film shrinks.

(2) when the machine is stopped, the upper film stays in the heat sealing plate for a long time, the film receives most heat, and the film shrinks.

(3) there are wrinkles on the film before heat sealing.

(4) there is a foreign body on the heat sealing plate or a scar on the heat sealing plate.

(5) the heat sealing gasket is not smooth.

Solution:

(1) reduce the heat sealing temperature, reduce the heat of the upper film, reduce the shrinkage of the upper film.

(2) in order to ensure that the film has been running production, reduce the number of shutdown, in order to reduce the problem of too much heat on the film when the shutdown, to avoid the film heat shrinkage deformation formed by the wrinkle.

(3) there are wrinkles on the film before heat sealing. If the film is on, it is required to control the quality of the product in the production process to avoid wrinkles;If there is a wrinkle before stretching the film, it is required to control the quality of the product in the production process to avoid wrinkle.If the lower film is wrinkled in the stretching process, it means that the lower film is heated too much in the stretching process, reduce the stretching temperature, stretching preheating time and stretching forming time;Or the lower membrane is stretched heating plate with foreign body, plate injury, remove foreign body, repair heating plate.

(4) remove the foreign body on the heat sealing plate, and dress the heat sealing plate.

(5) dressing the heat sealing gasket to ensure that the heat sealing gasket is smooth, and there can be no gap.