For many companies in the chemical, building material or food industries, the efficient packaging of their palletized goods is a deciding competitive factor. Some of the crucial factors are transport security, anti-theft protection, display characteristics of the packaged goods, as well as weatherproofing for outside storage. Further key factors are process efficiency and cost reduction (energy and material consumption), as well as the system output (the number of pallets that can be packaged during a specific amount of time). All of these factors need to be taken into account in order to determine the perfect packaging technology. Stretch hooding has proven to be particularly efficient in comparison with other techniques.
Necessary for any industry
Palletizing and packaging play a particularly important role, in any industry, for delivering goods in optimum condition to customers. If the required stability is not provided, goods such as glass, stone or bricks stacked on trucks can detach from the palletized unit and break. This can cause tremendous costs, depending on the product. Materials such as cement, flour or cocoa powder need special protection against atmospheric influences and humidity during transport and storage. To accommodate this, there are different packaging solutions available to the customer. It is important to find the most economical and environmentally sustainable solution.
“It is important to find the most economical and environmentally sustainable solution”
Efficient packaging with shrink film
Film packaging for pallets was developed by a German chemical producer in the mid-1960s, based on using shrink film. The film is produced as a tube using blow head extruders with tubular dies, which are then further processed or slit open to become a flat film. Hot air heats the film during the shrinking process up to the softening point of around 120 degrees Celsius. The film is shrank to fit perfectly around the palletized goods, which, after cooling down, creates the necessary stability to secure the load. The heat required for the shrinking process is produced by the packaging system either electrically or with gas. If required, the pallet can be packaged leaving its base open for the skids of the fork-lift. This allows high-bay storage. It is also possible to draw the film over the pallet base. The shrinking method is particularly suited for products that are sensitive to elastic packaging stacking, such as glass. Besides securing loads, this technique also protects goods reliably against environmental impacts such as snow, rain, UV radiation, dust and insects. However, the shrinking process causes the film to become milky, which makes it difficult to see the packaged goods or imprinted barcodes. Additional disadvantages: polyethylene (PE) bags might weld to the packaging film.
Or opt for wrapping instead?
A decade passed before a US-based crude oil refiner and chemical resins supplier discovered the ingredients for a stretchable film, and the stretch wrapping technique was born. This packaging technique is still one of the most popular solutions with many companies, due to the low initial investment costs for the machines compared to shrink or stretch hood systems. The consumption of stretch wrapping film in Europe alone is estimated to be 1.4 million metric tons per year. This technique, however, requires a lot of material which means that the operator has to change the film roll frequently. This makes the technique suitable for low production rates. Stretch wrapping film consists of pure PE. Due to its particular elasticity, it solidifies the palletized goods during packaging. This technique, however, only provides little vertical tension force to the load, which is needed to provide stability for the transportation loads. This technique is not suited for materials with sharp edges, such as stones or bricks. Another disadvantage: additional plastic film is required to protect the goods against environmental impacts and humidity. The film overlay prevents an optimal display of the products and barcodes on the film cannot be read easily. Additionally, the statically charged film attracts dirt particles and gathers dust when stored over a longer period of time. The film also does not offer any protection against theft, as unauthorized persons can remove goods from the pallet without ripping the film. Another problem: projecting film remnants, typical with this packaging technique, can disturb the sensor system of the conveying technology or the rack feeders. This causes repeated error messages.
“The availability of improved raw materials allowed the quality of the film to be considerably increased”
High transport security with stretch hoods
The stretch hood technology is a combination of the film hood and stretch wrapping techniques. BEUMER installed the first stretch hood system in Belgium in 1988. But the largest breakthrough for this pallet packaging technique only came about 15 years ago. The availability of improved raw materials allowed the quality of the film to be considerably increased. Like shrink hooding, the stretch film adapts to any product that is stacked on the pallet. And similar to wrapping, the film is very elastic and therefore solidifies the material via contracting forces. This technique guarantees a high load stability. The packaging film does not get glued to the product during the process. It is possible to pack the pallet both for high-bay storage systems and with under stretch. The smooth film surface ensures high visibility of the packaged goods.