Fault: the dew point is too low, the polymer molecules oriented, so that the film performance is close to the directional membrane, resulting in reduced heat sealing performance; the blow ratio and traction than inappropriate (too big), film drawing orientation, thus affecting the sealing performance of the film.

Solution: adjust the air volume in the air ring size, the dew point high point, as far as possible in the plastic melting point of blowing and drawing, in order to reduce inflation and lead to the traction molecular orientation; the blow ratio and traction should be smaller than, if inflation is too big. And the traction speed is too fast, the transverse and longitudinal stretch film over, then, will make the film performances are biaxial tensile, heat sealing film will become worse.