The parcel is wrapped like a shrink film, wrapped around the tray around the tray, and then the two hot grips wrap the ends of the film together. This is the earliest use of stretch film, and thus the development of more packages
Full width wrapped
This package requires a film width sufficient to cover the shape of the tray, tray shape, so use it, suitable for film thickness of 17 ~ 35μm
This package is the easiest of wrapping the film, the film is mounted on a frame or by hand, by the tray or the film is turned around the tray. Mainly used in the package after the damaged tray re-wrapped, and ordinary tray parcel. This package is slow, suitable for film thickness of 15 ~ 20μm;
Stretch film winding machine wrapped
This is one of the most common and most extensive mechanical package, the tray rotation or film around the tray rotation, the film fixed on the bracket can move up and down. This package is very large, about 15 to 18 per hour. Suitable film thickness of about 15 ~ 25μm;
Horizontal mechanical parcels
Different from other parcels, from the film around the goods, suitable for long cargo parcels, such as carpets, plates, fibreboard, profiled;
Paper bag wrapped
This is one of the latest uses of the wound film, better than the old paper tube wrapped with wrapped film wrapped. Suitable film thickness of 30 ~ 120μm;
Small items wrapped
This is the latest wrapping film wrapped, both to reduce the material consumption, but also can reduce the storage space of the tray, abroad, this package was originally introduced in 1984, just a year later, the market there have been many such packages, This package has great potential. Suitable for film thickness of 15 ~ 30μm;
Tube and cable
This is an example of the application of the wound film in a particular field. The package is installed at the end of the production line. The fully automatic stretch film can either replace the tape with the material and protect it. Applicable thickness is 15 ~ 30μm.
The way the tray is wrapped
Stretch film parcels must be stretched, the tray mechanical stretch of the stretch method has a direct stretch and pre-stretch. Pre-stretching is divided into two kinds, one is the roll pre-stretching, one is electric stretching.
Direct stretching is done between the tray and the film to complete the stretch. This method has a low draw ratio (about 15% to 20%). If the draw ratio exceeds 55% to 60%, the film yield is reduced, the film width is reduced, Easy to break. And at 60% elongation, the tension is still very large, for light cargo, it is likely to make the goods deformation.
Pre-stretching is done by two rollers. The two rollers of the roll pre-tensioned are joined together by the gear unit. The draw ratio can be different depending on the gear ratio. The tension is generated by the turntable. Since the stretching is caused in the short distance, the friction between the roller and the film And large, so the film does not shrink, the film's original puncture performance is also maintained. The actual stretch does not occur during stretching, reducing the break due to sharp edges or corners, which can increase the draw ratio to 110%.
The pre-tensioning mechanism of electric pre-stretching is the same as that of roll pre-stretching, except that the two rollers are driven by electric force and the tension is completely independent of the rotation of the tray. So the more adaptable, light, heavy, irregular goods are applicable, due to the low tension when wrapped, so this method pre-stretch rate of up to 300%, greatly reducing material costs. Suitable for film thickness of 15 ~ 24μm.