Download this free, 140-page Flexible Packaging Playbook jam-packed with strategies for success, best practices, and pitfalls to avoid.  Learn more »
Glenroy invites you to download this playbook.
Article |

Herrmann Ultrasonics, Inc: Ultrasonic sealing for snack bags saves material

Herrmann Ultrasonics’ new ultrasonic seal tool uses an anvil contour to create a tight, peelable seal of composite films, similar to a heat seal in appearance, for the chips and snack industry.

In the ultrasonic sealing process, the packaging materials to be joined are placed between the sonotrode and the anvil.  In order to focus the ultrasonic energy, small bundled contours (top, radius, or plateaus which are arranged as vertical lines) in the anvil are necessary. The seal quality depends on the line height, distance, quantity, and design of this contoured anvil.

Ultrasonic seals of metallic foils are peelable starting at widths of 7mm. Therefore, it is possible to reduce the overall amount of the packaging material.  Heat seals typically have a seal width of 15 to 24mm. The percentage of the area of a typical heat seal is approximately 8% to 12% of the package. This can be reduced by 50% when sealing with ultrasonics.

The overlap longitudinal seal (back seal) can also be sealed with ultrasonics, offering a similar tight seal.

The ultrasonic tooling remains cool, which eliminates shrinking and visual changes to the foil structure.

The correct sealing force insures an even distribution of the created flow of the seal layer, with few wrinkles, providing an even distribution of force across the length of the seal. This is critical for the peelability of the seal.

It is easy to peel a seal if it has a cohesion fracture (separation of the seal layers of the films) resistance of 4 to 6 N/15mm over the length of the seal. It is difficult to peel seals that have an adhesive fracture resistance in the area of the seal (delamination).


Related Sponsored Content

42 Best Package Designs: All New for 2016
Sign up to receive timely updates from our editors and download this e-book of our editors’ selections for most innovative package designs of the past year.


Don't miss intelligence crucial to your job and business!
Click on any newsletter to view a sample. Enter your email address below to sign up!
Each newsletter ranges in frequency from once per month to a few times per month at most.