Wrinkle the foil around the stack
One of the main problems that is related to temperature. If there is a wrinkle after heat has been applied, it means that it is not enough. More heat should be applied.
If you’re using a hot air gun, increase the temperature. If you are using a heating tunnel, reduce the speed of the tape or increase the temperature of the heaters or burners.
In the corners of the packaged product, a triangular protrusion is formed without the foil being tightly adhered to the product. This is the most frequent problem when packing with heat shrink film.
Check the heating. To prevent canine ears, more heat should be used. Another reason for their formation may be too large a size of the foil.
Bulging of the foil
It is obtained by unnecessary air entry between the foil and the packaged product. It occurs after heating. It is difficult to predict in which individual pieces or products the foil will be bulging.
Small holes with a needle with which to make ventilation holes helps to reduce and solve this problem.
It is obtained with the use of too much heat.
If you’re using a hot air gun, keep it at a greater distance. If you are using a heating tunnel, increase the speed of the tape or reduce the temperature.
Ruptures are caused by an inappropriate choice of foil or its inappropriate thickness for the product we pack.
If you get frequent ruptures, consider foil of greater thickness. If you are using PVC film, consider replacing it with polyethylene shrink film.