The working principle and use of shrink packaging machine

 The automatic packaging machine that wraps the product with heat-shrinkable film and then heats it and shrinks the film and then shrinks the product is called shrink wrapping machine. Shrinkage packaging machine according to the machine type is divided into tunnel type shrink machine, oven type shrink machine, frame type shrink machine and gun type shrink machine.


Automatic shrinkage packaging machine is mainly composed of wrapping machine, heat shrinkage channel conveying device, etc.Conveying device will be packaged goods according to the packaging specifications into the packaging machine, with shrinkable film to wrap and seal, and then into the heat shrinkable channel, so that the film shrinkable goods tightly wrapped.


Shrinkage packaging machine is widely used, mainly used for packaging sales and transportation, can wrap food, daily products and industrial products, etc.Can be single packaging, also can be multi - packaging.It is especially suitable for packing articles with irregular shape.


At present, the most used shrinkable film materials are: polyvinyl chloride, polyethylene and polypropylene, but also the use of vinylidene chloride, polyester, polystyrene.Its main technical indicators include: shrinkage rate, shrinkage tension, shrinkage temperature, heat sealing, etc.Shrink film commonly used, most of the longitudinal and horizontal shrinkage requirements are about 50%, there are also special requirements of the vertical and horizontal direction of the shrinkage rate is different.


Shrinkage temperature is lower as well, especially for fresh food, fiber products and other packaging pay more attention to this point.


In the shrink packaging machine, there are three kinds of film wrapping methods for items, one is open at both ends, open at one end and fully enclosed.


Open wrapping method at both ends. If the tubular shrinkable film is used, the opening of the tubular film should be expanded, and then the article should be sent into the membrane tube. The size of the membrane tube should be about 10% larger than the size of the article.This wrapping method is more suitable for cylindrical items (such as batteries, film, paper rolls, wine bottles, etc.).


One end of the open wrapping method is to use a tube shrinkable film to cover the article and the end of the sealing;It is also possible to prefabricate the tubular film or flat film into a bag first, and then wrap the goods. The wrapping method is generally to pile the goods on the pallet and wrap them together with the pallet, which is mostly used as a transportation package. The size of the prefabricated bag is generally 15%-20% larger than the pallet accumulation.When wrapping the bag, stretch the bag open to cover the tray and debris.


The fully enclosed wrapping method is to wrap the goods around (when using flat film) or at both ends (when using tubular film). It is mainly used for the packaging of products with good sealing, such as bowl noodles, etc.Tube film, double folded film and tensioned film can be used for wrapping.Using flat film, can be used three sides sealing pillow packaging form wrapping articles, suitable for long column articles wrapping.Horizontal wrapping machine is often used, and its working principle is the same as that of horizontal bag forming-filling-sealing machine.When the size of the package is large, it is necessary to use double film for fully enclosed wrapping.

Heat shrinkable device uses hot air to heat the wrapped items to shrink the film. Put the wrapped items on the conveyor belt and send them into the shrinkable device (tunnel) for heating with hot air.After heating, the film is tightly wrapped on the package, and output after cooling.In general, most heat-shrinkable tunnels are electrically heated.In order to ensure that the hot air can be evenly blown to the packaging, so that the film shrinkage uniform, the general use of automatic temperature adjustment device to ensure the temperature constant, and the forced circulation system to ensure the circulation of hot air.Usually, in the transmission system, there is a stepless speed regulating device or a speed regulating motor to facilitate the adjustment of the heat shrinkage time.