Optimal protection, optimal cost efficiency

Wrapping, shrinking or stretching? Comparing packaging technologies

For many companies in the chemical, building material or food industries, the efficient packaging of their palletised 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.

Palletising and packaging play a particularly important role, in any industry, for delivering your goods in optimum condition to your customers. If the required stability is not provided, goods such as glass, stone or bricks stacked on trucks can detach from the palletised 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. There are currently three different palletising packaging techniques on the market: shrink hooding, stretch wrapping and stretch hooding.

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. The film is shrunk to fit perfectly around the palletised 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. The goods are reliably protected 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 and the heat effect can be a fire hazard.

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.

The stretch wrapping film's elasticity allows solidifying the palletised 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. And because the film is wrapped, you cannot print on it. Additionally, the film attracts dirt particles due to its adhesion properties and the products collect dust during longer storage periods. The film also does not offer any protection against theft, as unauthorised 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. Due to the many setting parameters, the quantity of the film required for the packaging cannot be calculated exactly.

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 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 understretch. The smooth film surface ensures high visibility of the packaged goods, and therefore provides an excellent display of the packed goods at the Point of Sale because barcode labelling is quickly and consistently recognisable. The used film is recyclable. Stretch hooding does not use heat, which reduces the fire hazard considerably, increases operational reliability and therefore minimises insurance rates. Less film and energy are required, which means less damage to the environment. In the majority of industrial and consumer product applications, stretch hooding offers the best possible protection for palletised goods. A sheet placed on the pallet offers additional protection on six sides against external influences with this packaging solution. It allows for a clean and dry outdoor storage, as goods are reliably protected against environmental impacts, humidity, insects and UV rays.

Packaging solutions compared

The BEUMER portfolio includes innovative solutions and systems for all these packaging techniques. But in order to stay competitive in the long run, companies should not only consider the total cost of ownership when making investment decisions. A comprehensive approach is necessary to determine the perfect packaging method. By considering the total value of ownership (TVO), the efficiency of the operating investments can be specified more comprehensively and in more detail. This is why BEUMER Group considers economical, ecological and social aspects when developing their plants and systems. This allows our customers to plan their investments strategically.

Double your throughput with stretch hooding

Besides load securing, another important factor for most companies when choosing the perfect packaging method, is the protection against environmental impacts. This is why the BEUMER experts compared shrink hooding to stretch hooding and found a clear cost advantage for the stretch method. They took a palletised stack of 1,630 millilitres in height for test purposes. Systems that use shrink hooding to package palletised items can process 35 to 70 pallets per hour. With this process, the film strength lies between 120 and 180 micrometres. By using the stretch hooding method, throughput is nearly doubled with 100 to 120 pallets per hour. The film that is used is also thinner, only 70 and 140 micrometres. Less material is required due to the elasticity of the film.

In 2014, the market price for shrink film was at 1.70 EUR per kilogram. The packaging costs for a film hood were approx. 1.02 EUR. The film costs for 300,000 pallets per year were approx. 306,000 EUR. The film used for stretch hooding is currently slightly more expensive with 1.90 EUR per kilogram. To form a film hood, however, you only require materials totalling 57 cents. This leads to a remarkable cost difference of approx. 159,000 EUR for the same amount of pallets per year. The customer can achieve cost savings of approx. 52 percent.

The systems also differ in regards to their energy demands. The gas consumption for shrink hooding is at approx. two kilowatt hours per pallet. The energy required to form a stretch hood costs six cents. For the calculated 300,000 pallets per year, the total cost is 18,000 EUR. Due to the fact that the stretch hood system works without gas and the costs for energy consumption are almost identical for both techniques, the user can save those costs by implementing the stretch hood method.

The maintenance costs for shrink hooding can vary, especially for older machines, between 2,000 and 8,000 EUR per year. We used 4,000 EUR as the basis for our calculation. The calculated average costs for the stretch hooding method are between 1,000 and 3,000 EUR per year. Assuming an average value of 2,000 EUR, the user saves 2,000 EUR per year in maintenance costs. This means significantly lower costs per year when using the stretch hooding technique.

The BEUMER stretch hood® A is the result of the intralogistics specialist from Beckum redesigning its tried-and-trusted packaging system from scratch. During its development, our specialists analysed various components and optimised them in terms of function, arrangement and ergonomics. This includes an intuitive menu system on the machine control via a soft-touch panel, an optimised, ergonomically designed workplace for the operator and material-friendly transporting of the film in the machine thanks to an innovative film transport system. The new system also features improved system performance and requires far less floor space.

Tailored solutions

Each product has its own handling characteristics, which require a careful analysis by the user. This analysis is necessary to determine the pallet packaging requirements. BEUMER provides the operator with an online configurator to calculate and evaluate the economic efficiency of different packaging techniques, as well as the added value for their company. In addition, BEUMER experts will create a presentation that is individually tailored to the customer's requirements. The customer gets a reliable comparison between the different packaging methods, the individual energy consumption, as well as the maintenance, investment and system costs.