The sealing process of containers (seals for bottles), the forgotten pillar of a good production line

Seals for bottles

The sealing process, such as seals for bottles, is perhaps one of the most undervalued elements of the production line. From product quality to production speed to uptime and design, it affects essential aspects of brand image and ultimately the success of the business. 

However, the result depends on how the technology is adapted to the individual product, the environment, the production parameters and the materials.

  • Why is sealing so important in packaging?

Sealing technology is of vital importance to manufacturers. It can make or break a production process. With the right method, sealing not only ensures product safety and quality, but also has the potential to improve presentation and ease of use, making a brand more appealing. 

On the other hand, improper sealing can affect product quality, which could have economic consequences and negatively affect the brand. In operational terms, sealing is often the bottleneck that negatively affects the efficiency and speed of the entire packaging process. 

  • What do manufacturers expect from sealing?

Manufacturers’ needs can be summed up in two main factors: quality and efficiency. Companies are under constant pressure to reduce costs while delivering the best possible seal. 

For this reason, they sometimes ask us for solutions that enable the use of cost-effective films that, at the same time, ensure hermetic sealing and durable packaging, all as part of a robust packaging process that reduces downtime and waste and protects the product perfectly.

  • Can you briefly explain how the seals for bottles process works?

To create a flow-wrap package, the film is molded into a tube with a long seal. Two cross seals then completely envelop the product and seal the package hermetically.

It is common knowledge that sealing is nothing more than a combination of temperature, pressure and time. Choosing the right film is another key factor in this process.

However, when it comes to the most important factors in the flow-wrapping process, time is key, especially for cross seals. Therefore, Bosch offers several different sealing movements; extending the sealing time to the maximum without slowing down the packaging line. With rotary sealing, the sealing tongs are brought together and pressed to form the seal. 

In extended dwell sealing applications, the sealing tongs close and then follow the movement of the film, resulting in seal times up to 20 times longer than rotary sealing and providing airtight packages.

However, this sealing method has a mechanical limitation of 40 meters of film per minute. Amplified heat sealing (AHS) is Bosch’s latest innovation in sealing technology. 

The rotary sealing unit moves with the film, allowing sealing time to be extended four times longer than with a static rotary station. This technology, in which the film can reach a speed of 70 m/min, is midway between rotary and extended dwell sealing and combines the advantages of higher seals for bottles integrity at higher speeds.

  • What are the main challenges manufacturers face in the sealing process?

Manufacturers face the challenge of having to combine product quality with speed, efficiency and cost. No two projects are the same, as the process can be affected by many variables, such as product consistency, overall speed and speed variations during the process, packaging style, industry standards, climate, film type(s) and shelf life. 

In addition, waste must be kept to a minimum. With all these parameters to consider, it is essential to apply the right technology for a specific product and production process.