1. Sealed packaging
This kind of packaging is similar to shrink film packaging. The film wraps the tray around the tray, and then two thermal grippers heat seal the film at both ends. This is the earliest use form of stretch film, and more packaging forms have been developed from this
2. Full width packaging
This kind of packaging requires the film to be wide enough to cover the pallet, and the shape of the pallet is regular, so it has its own, suitable for film thickness of 17～35μm.
3. Manual packaging
This kind of packaging is the simplest kind of stretch film packaging. The film is mounted on a rack or hand-held, rotated by the tray or the film revolves around the tray. It is mainly used for repackaging after the wrapped pallet is damaged, and ordinary pallet packaging. This kind of packaging speed is slow, and the suitable film thickness is 15-20μm;
4. Stretch film wrapping machine packaging
This is the most common and extensive form of mechanical packaging. The tray rotates or the film rotates around the tray. The film is fixed on a bracket and can move up and down. This kind of packaging capacity is very large, about 15-18 trays per hour. The suitable film thickness is about 15-25μm;
5. Horizontal mechanical packaging
Different from other packaging, the film is revolved around the article, which is suitable for long goods packaging, such as carpets, boards, fiberboards, special-shaped materials, etc.;
6. Packaging of paper tubes
This is one of the latest uses of stretch film, which is better than the old-fashioned paper tube packaging. The suitable film thickness is 30～120μm;
7. Packing of small items
This is the latest packaging form of stretch film, which can not only reduce material consumption, but also reduce the storage space of pallets. In foreign countries, this kind of packaging was first introduced in 1984. Only one year later, many such packaging appeared on the market. This packaging form has great potential. Suitable for film thickness of 15～30μm;
8. Packaging of tubes and cables
This is an example of the application of stretch film in a special field. The packaging equipment is installed at the end of the production line. The fully automatic stretch film can not only replace the tape to bind the material, but also play a protective role. The applicable thickness is 15-30μm.
9. Stretch form of pallet mechanism
The packaging of stretch film must be stretched, and the stretching forms of pallet mechanical packaging include direct stretching and pre-stretching. There are two types of pre-stretching, one is roll pre-stretching and the other is electric stretching.
Direct stretching is to complete the stretching between the tray and the film. This method has a low stretching ratio (about 15%-20%). If the stretching ratio exceeds 55%～60%, which exceeds the original yield point of the film, the width of the film is reduced, and the puncture performance is also lost. Easy to break. And at 60% stretch rate, the pulling force is still very large, and for light goods, it is likely to deform the goods.
The pre-stretching is done by two rollers. The two rollers of the roller pre-stretching are connected together by a gear unit. The stretching ratio can be different according to the gear ratio. The pulling force is generated by the turntable. Since the stretching is generated in a short distance, the friction between the roller and the film It is also large, so the film width does not shrink, and the original puncture performance of the film is also maintained. No stretching occurs during actual winding, which reduces the breakage caused by sharp edges or corners. This pre-stretching can increase the stretching ratio to 110%.
The stretching mechanism of electric pre-stretching is the same as that of roll pre-stretching. The difference is that the two rolls are driven by electricity, and the stretching is completely independent of the rotation of the tray. Therefore, it is more adaptable, suitable for light, heavy, and irregular goods. Due to the low tension during packaging, the pre-stretching ratio of this method is as high as 300%, which greatly saves materials and reduces costs. Suitable for film thickness of 15-24μm.
Post time: Jul-14-2021