Riding the waves

1 November 2012



Bosch Packaging Technology head of research and development Prof Dr Bernd Wilke explains why ultrasonic technology is a key to environmentally friendly and profitable production


F ood manufacturers face growing regulation in the area of product safety. The drive towards sustainability and preventing food waste is gaining major significance within the packaging industry, while rising prices and heightened competition are increasing the focus on saving resources and costs through more efficient processes. Packaging systems with maximum overall equipment effectiveness (OEE) enable this optimal usage of resources.

Ultrasonic sealing technology is one possibility that enables manufacturers to reduce both costs and product waste while providing strong product protection. Reduced energy consumption, material savings and increased equipment availability allow manufacturers to produce more sustainably and profitably. In comparison with other sealing methods, such as hot and cold sealing, ultrasonic technology is an attractive alternative.

Assured product quality

Ultrasonic sealing offers crucial benefits from a product safety perspective. The new technology avoids the risk of diminished seam quality and leakage due to contamination of the sealing area, by using high frequency vibrations that remove product residues. The resulting sealed seams are secure, ensuring the product is tightly packaged.

Conversely, one drawback associated with the often-used hot sealing method is the negative influence on product quality by the required sealing heat. The high temperature of the sealing jaws can cause product damage: here ultrasonic’s ‘cold’ approach is a major advantage. Since the tools used are cold, the sealed seam can be placed close to the product without having a negative impact on its quality.

Ultrasonic technology can further benefit manufacturers by removing the risk of heat-related damage to materials or products in the event of machine stoppages.

A popular alternative in the past, when packaging heat-sensitive products such as chocolate, was to use cold sealing film. One disadvantage of this approach is the limited storage life of the film, which tends to stick together or to the product. Furthermore, the relatively high costs involved with cold sealing film have encouraged manufacturers to consider alternative sealing methods, including ultrasonic technology.

Saving resources

Ultrasonic sealing provides significant savings in terms of the energy required for the packaging process. The film is not heated from the outside inwards, but as a result of molecular vibration within the film.

As such, the temperature needed for welding purposes is generated inside the film in the actual sealed seams. This means, for example, a horizontal flow wrapping machine requires only 4.0 joules for sealing, compared with hot sealing with 6.7 joules.

As a further benefit, savings can be made in material costs. For horizontal packaging applications, manufacturers can use less expensive film materials, replacing the kinds of film previously required with thinner and more cost-effective alternatives.

In addition, the narrower sealed seams possible with ultrasonic technology reduce the amount of material needed. With vertical form, fill and seal machines, up to 16mm of film can be saved per package in terms of bag length.

The ‘cold’ ultrasonic sealing technology also eliminates the need to clean hot sealing jaws. By reducing the issue of film sticking to the heated jaws, ultrasonic technology ensures that there is less material residue after sealing and fewer defective packages.

Flexibility for manufacturers

Ultrasonic sealing technology from Bosch Packaging Technology is currently available for long and cross-sealing stations on its horizontal flow wrapping and vertical form, fill and seal machines.

Examples of horizontal flow wrappers for ultrasonic sealing are the Sigpack HCUR, the Sigpack HCUL and the Miniwrap BVK 2000 UA, which respectively use rotary and long dwell cross-sealing stations.

Bosch also offers vertical form, fill and seal machines incorporating ultrasonic sealing technology. Two examples are the SVE 3615 LR with cross and long-sealing, and the SVE 2520 AR using ultrasonic technology for cross-sealing. The typical pack styles produced on these types of equipment are block-bottom, pillow, gusseted and doy-style bags.

With horizontal bag types, ultrasonic can be used for both single packs and multipacks.

Bosch Packaging Technology

The Bosch Packaging Technology division, based in Waiblingen, Germany, is one of the leading suppliers in the field of processing and packaging technology. In more than 15 countries worldwide, it develops and produces complete solutions for the pharmaceutical, food and confectionery industries. A comprehensive service portfolio is complemented by local contacts offered through the company’s worldwide sales and service network.

E-mail: bernd.wilke@bosch.com

Views expressed on this page are those of the author and may not be shared by this publication.


Prof Dr Bernd Wilke Prof Dr Bernd Wilke

Prof Dr Bernd Wilke Prof Dr Bernd Wilke


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