Film welding is important for the packaging industry, for instance. Here, fine films can be welded with each other or with other materials. This is how coffee capsules, drinks packaging and much more are made. The special feature in the ultrasonic welding of films: The heat is generated within the material and not applied from outside. This means that the required temperature is not too high and the film is not damaged. Film shrinkage is prevented.
The high voltage produced by the generator is transformed into mechanical vibration (ultrasonic) in the converter. The weld tool (sonotrode) transfers this to the films to be welded. Friction heat is generated, the film heats up within a short time. The pressure from the sonotrode on the foil creates the joint and, at the same time, the weld joint is cooled down, as the weld tools do not heat up.
The ultrasonic sealing process can help to join fine films or laminates. The ultrasonic waves cause the molecules of the layers positioned on top of one another to vibrate. The friction leads to local heat development at the contact points of both layers. There, the materials are joined and a weld joint is formed. Once the joint is cooled down, the connection is almost as solid as the starting materials.