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Top 10 Frequently Asked Questions at RHM Packaging

At RHM Packaging we recently collected questions that have been asked by our customers. Welcome to our Customer Insight FAQ, designed to give you informative answers to frequently asked questions. Let’s dive in!

TOP 10 FAQ at RHM Packaging

1. What are stretchhood machines and how do they work?

Using Stretchhoods is a method of pallet packaging that safeguards the pallet by employing a flexible hood which conforms to the shape of the load without requiring any heat application. This technique utilizes a tubular stretch film, known as Stretchhood film, which elongates and getting pulled over the load, enveloping it entirely and providing protection from 5 sides.

2. How is it possible to save costs while using stretchhoods?

The use of stretch hoods offers numerous opportunities for cost savings throughout the entire pallet wrapping process. There are several approaches to saving costs:

Optimize film: By using film more efficiently, material consumption per pallet and the resulting waste can be minimized. The format, processing and thickness of the film can be examined and optimized. The quality of stretchhood films has constantly developed in recent years due to the use of new materials, which means it often makes sense to check the current status quo of your packaging and thinking about enhancing your film usage.
- Film format: The film format consists of a long side with a gusset that lies against the short side of the pallet. Due to the increased flexibility of the films, it may be possible to use a smaller format that is expanded further during the packaging process than before and then adapts to the load accordingly.
- Reduce Film bags: In some cases, 2 stretch hoods are pulled over a pallet for reasons of stability or for weather protection. However, with the right receipe, weather protection can also be achieved with one stretchhood – it depends on the proportions of UV-protecting materials. The stability of the pallets can also be influenced and optimized through the recipe and the use of different materials.
- Reduce film thickness: Due to the use of new materials and increased flexibility, it is often possible to use a thinner film without losing stability or affecting the reliability of the packaging process. This offers further advantages, as more running meters fit on the film rolls and they have to be changed less often.
Interaction between film and machine: The above-mentioned film optimizations can only be implemented through the interaction of machine and film. The condition of the machine has a significant influence on the processing of the film and its stretching – it is very important here, for example, that high-quality film grippers are used. If the edges are sharp or the grippers cannot be adjusted precisely, the film cannot be processed optimally.
Save energy: Operating costs can be saved by switching from a comparatively expensive operation of a hydraulic machine to an electric machine. The frame of the machines can be exchanged and converted from hydraulics to electrics. Switching from shrinkhood to stretchhood also saves a lot of energy because the heating process is no longer necessary. (see more in the last question – 10)
Extending the lifetime of your machine: With regular service and maintenance it is possible to keep your stretchhood machine up to date, which postpones the purchase of a new stretchhood machine for several years and increases the return of investment (ROI) of your machine. Costly downtime due to sudden problems can be avoided in the long term so that your production always stays in flow. Also major changes through retrofits can extend the life of the machine by several years and make the packaging process more cost-efficient. Retrofitting can not only make your machines more energy efficient, but also process the film better and increase the throughput of pallets to be packed.
Avoiding transport damage: If goods break during transport between your factory and the customer, costs may arise. Therefore, stable loading unit securing of the pallet and load securing on the truck is very relevant in order to avoid this. If you already have problems in this area, it often makes sense to examine your packaging process closely and optimize the stability of the

Overall, the combination of material savings, lower energy consumption, improved operational efficiency and improved load protection make stretchhood machines a cost-optimized packaging solution. In our DUO PLAST and RHM technology center, your film can be examined in detail and optimized with our stretchhood machine and then transferred to your packaging process at your factory. This means that the machine and film can be optimally coordinated with one another. The processing of stretch hoods is always fully automatic and therefore requires comparatively little personnel effort. Compared to other packaging methods, a high throughput can be achieved in a relatively short time with around 150 packed pallets per hour.

3. What type of film is used for stretchhoods and what characteristics does the film need?

Stretchhood film represents an innovative approach to pallet packaging, continually evolving to deliver diverse gripping and protective outcomes. This multilayer tubular film primarily comprises Linear Low-Density Polyethylene (LLDPE) and sometimes to a lesser extent Ethylene Vinyl Acetate (EVA) polymer. This material offers more flexibility but has a slightly higher cost and in the past there have sometimes been problems with the supply reliability of EVA. This is why metallocene materials are increasingly being used in stretchhoods, as they have better availability than EVA. Furthermore, these materials have been cheaper, but they are currently becoming more and more similar due to demand.

These materials are selected for their impermeability, stretchability, and elasticity. Outer layers are enriched with additives to enhance resistance against puncturing, friction, and ensure sealing and waterproofing, predominantly composed of LLDPE.

There are three primary material types utilized in producing stretchhoods:

Mainly LLLDPE with a metallocene materials: This variant offers robustness suitable for conforming to the shape of goods tightly, delivering high holding and restoring forces at a more affordable cost.
Mainly LLDPE with a Low Percentage of EVA: Offering increased flexibility, this type is favored for packaging shapeless products and meeting specialized requirements. Mainly LLDPE with a low EVA content: This type offers greater flexibility and is favoured for the packaging of shapeless products and the fulfilment of special requirements.
Stretchhoods Incorporating 30% Post-Consumer Recycled Material: Addressing environmental concerns, these variants aim to minimize their ecological footprint by integrating recycled materials. This initiative aligns with efforts to establish a closed-loop system for polyethylene, ultimately reducing waste through material downsizing and recycling.

By prioritizing sustainability and innovation in material selection and design, the stretchhood film industry endeavors to minimize its environmental impact while delivering effective pallet packaging solutions.

4. Does Stretchhood protect your loads during transport and handling?

Depending on the type of load, the Stretchhood provides total support for transport and handling. This is the case for stable pallets (e.g., for sack loads) or light pallets (e.g., for logistics or pharmaceuticals).

If you want to pack your load with stretchhood, there are several ways to check the unit load security of the goods.

In the technology centre of our partner DUO PLAST and RHM, we can check which stretchhood and which machine setting (e.g. stretch) is suitable for your goods. Stretchhood is always secondary packaging, so it is important to check the entire pallet for stability – this means the entire load unit and also the load securing on the lorry. In this way, transport damage can be avoided in the future and material utilisation can be optimised.

We have the following test methods in the technology centre:

Stretchhood Machine: Adjustments and optimizations can be made to stretchhood machine settings and optimize the entire packaging processes without interrupting production. Various films with different materials and thicknesses are tested to assess stability.
Horizontal Impact: Simulates important shock and acceleration loads during horizontal transport. Various acting forces can be measured, usually in a range between 0.5 g and 0.8 g, as this corresponds approximately to the forces of a lorry braking on the road. It is also possible to simulate the coupling of rail vehicles or, for example, handling work in warehouses/distribution centres – the tests are possible with forces of up to 15g.
Vertical Vibration Table: Tests vertical shocks and vibrations to examine load unit behavior under different conditions. This simulates shock absorbers on a lorry, turbulence in air traffic and the effects of processing the load in warehouses.
Pitch & Roll module: Analyzes stress from tilting movements and rotations, simulating realistic cornering and shipping movements. The Pitch & Roll module is integrated in the Vertical Vibration Table – this interaction makes it possible to cover very application- orientated requirements, as the combination of different loads at the same time creates very realistic test conditions.
Climatic chamber: Evaluates the influence of climatic conditions on the strength of the packaging and the holding forces, taking into account temperature fluctuations between – 25°C and 80°C and a humidity of between 15% and 98%.
GPS data recorder: Provides detailed transport route analyses, measuring direct and indirect influencing factors such as forces, accelerations, temperature, and humidity.

If you already have a stretchhood machine, it is possible to carry out a tilt test. This involves lifting a pallet with the stacker on one side and tilting it to a certain angle. However, this test method is very imprecise in comparison.

Thanks to advances in the development of stretchhood films, there are more and more films with increased strength and hold-down force on the market that makes it possible to secure the load with a single hood. The key to securing lies in the properties of the film in combination with the correct stretch application by the stretchhood machine.

5. Can a stretchhood machine be integrated into an existing packaging line?

Integrating a stretchhood machine into an existing packaging lane involves careful consideration and planning to ensure seamless integration and optimal performance. While the specific process may vary depending on factors such as the layout of the packaging line, the type of products being packaged, and the existing machinery setup, it is generally possible to customize the integration to fit the unique requirements of the operation.

The first step in integrating a stretchhood machine is to conduct a thorough assessment of the existing packaging line. This includes evaluating the available space, the workflow of the line, and the compatibility of the stretchhood machine with other equipment in the line. Based on this assessment, modifications may need to be made to the layout or configuration of the line to accommodate the new machine.

6. Is there a schedule of recommended service intervals?

How often a service needs to be carried out on your machine depends, for example, on the usage and the machine model. As a rule of thumb, we recommend one service per year for average use – or even twice a year for very intensive use. There are also service recommendations for certain wearing parts: for example, the sealing bars should be replaced approximately every 30,000-35,000 pallets, as otherwise the risk of fire increases and the sealing seam of the film can no longer be processed properly – the stretchhood can therefore open from above.

A proactive approach to servicing not only ensures the continued reliability of your machine, but also contributes to cost savings by avoiding costly repairs that can result from neglected maintenance. For each stretchhood machine model, we can provide you with detailed service interval schedules to suit your usage.

If your machine has not been serviced for some time, it makes sense to have all wear parts checked by service technicians and to have the condition of the machine checked.

7. How do I recognise that my stretchhood is not being processed optimally?

We have prepared a checklist for you of the problems that can occur when processing stretchhoods. If one of these problems occurs, you should have the stretchhood machine checked by a technician, as adjustments to the machine or a different film may be necessary:

A lot of material is being used
The film often tears from the bottom or top
One or more grippers are not gripping the film properly
The sealing seam bursts/tears while the film is being stretched
Holes appear when the film is stretched or
Holes appear when the film is pulled over the pallet
Machine Errors
Uneven film tension
Large creases at the corners or a lot of loose film at the top of the pallet,
which can result in large upright creases
Lack of bottom stretch: the film slips off the grippers and remains on one
or more corners of the pallet
Cut edge of the hood is not clean

8. How can I make my packaging process with stretchhoods more sustainable?

There are several options to process you stretchhood more sustainable and reduce your CO2-Emssions.

Energy-Saving: It is possible to integrate various energy-saving features and technologies into your stretchhood machines. These may include advanced control systems that optimize machine performance and energy usage, such as converting your stretchhood machine from hydraulic to electric. Additionally, we can provide guidance on optimizing machine settings and usage to minimize energy consumption without compromising.

Reducing Material Consumption: Downsizing of stretchhood reduces the consumption of material and waste. This contributes to the preservation of valuable resources and helps mitigate the strain on the environment.

Using Stretchhood Film with recycled content: The aim is to build up a closed-loop system for polyethylene, minimizing waste and environmental impact. PCR (Post-Consumer-Recyclate), derived from recycled consumer packaging waste, is processed into a new raw material. Utilizing stretchhoods with 30% PCR content offers an eco-friendly transportation packaging solution. Overall, incorporating compared to using virgin materials.

Extending the life of your machine is crucial for resource conservation and sustainability – there are several ways: Service can significantly contribute to this goal. Giving a new life to a used machine not only saves waste but also conserves resources by adapting the machine to the company’s requirements. Utilizing high-quality spare parts ensures reliability and durability, reducing the need for frequent replacements. Additionally, modernizing existing stretchhood machines with retrofit options is an energy-efficient way to upgrade them, further enhancing their efficiency and sustainability.

9. In which industries are stretchhoods often used?

Stretchhood packaging is used in a variety of industries and applications. They are mainly used for the packaging of bagged goods and bucket goods:

Construction: The construction industry uses stretchhood packaging to protect building materials such as bricks, tiles, cement bags and insulation during transportation and storage.
Food and Beverage: stretchhood wrapping is a preferred method for packaging pallets of food, beverages and pet food, ensuring hygiene and protection throughout the supply chain.
Whitegoods: Stretchhood packaging is utilized to protect household appliances such as refrigerators, washing machines, and ovens during transportation and storage, ensuring they reach consumers in pristine condition.
Chemicals: In the chemicals industry, stretchhoods ensures the safe and secure packaging of various chemical products, including powders, granules, and liquid containers.
Horticulture: Stretchhoods are often used for packaging agricultural products such as fertilizers or potting soil bags to protect them from moisture and sunlight.

10. How does stretchhood machines compare with shrinkhood machines and stretchfilm machines in terms of performance and costs?

Stretchhood Machines and Shrinkhood machines pallet packaging are sharing only one commonality: the use of a tubular film to safeguard the load. However, they diverge significantly in their operational approach.

In the heat shrink system, a tubular film with shrink properties is applied to the load. Heat is then employed, typically through combustion burners, causing the film to shrink tightly around the load. This process consumes a substantial amount of energy for combustion and necessitates a larger quantity of film relative to the load’s dimensions and thickness.

The Stretchhood machine utilizes a tubular film that stretches to conform to the load without requiring heat. The film’s dimensions are slightly smaller than those of the load, allowing it to compress and secure the load as it is stretched over it. This eliminates the need for heat shrinkage and significantly reduces the amount of film used for protection. Consequently, the Stretchhood method can offer cost savings compared to the shrink hood method, as less energy and material are consumed overall. Additionally, the stretching process with the stretchhood is faster than shrinking with the shrink hood, saving time in the packaging process.

Finally, the stretchfilm machine – a flexible plastic film is wrapped around products or pallets to provide stability and protection to the load. It can be used manually or with a pallet wrapping machine. One advantage here is that the film can be layered more tightly where additional stability is needed – usually at the connection between the product and the pallet. In this way, material savings are also possible if less film is used where less stability is required. This method often results in a lower pallet throughput compared to the stretch hood machine.

Are you unsure which packaging method is best suited to your packaging requirements?

You are welcome to bring pallets with your goods to our technology centre for testing purposes. There we have a stretchhood machine and various stretchfilm wrappers to find the optimal packaging solution for you. The pallets can then be checked for their stability so that no more transport damage and its resulting costs occurs in the future.