Ultrasonic Punching

The patented ultrasonic punching from SONOTRONIC enables precisely defined openings of very high quality to be made in plastic components or textiles. In addition, the material can also be embossed or welded at the edges during the punching process.

The patented ultrasonic punching system achieves the best possible quality whilst maintaining flexibility. No crazing or fluff is generated at the punched surface when plunge cutting. A further advantage is that with this process, decoupled, constant radial embossing is possible, irrespective of the material thickness. Punching itself is visually clean both for painted and unpainted plastics.

The process is similar to ultrasonic welding, with the difference that workpieces are not joined but separated. The ultrasonic oscillations heat the plastic in the separation zone, so that punching can be effected with reduced force (compared to the mechanical punching) by the blade edges of the tool. For this, either the anvil or the sonotrode prescribes the punch geometry. With this process, both the external and internal forms can be worked separately or together.

Ultrasonic punching  for external and internal forms

Ultrasonic punching with sonotrodes in knife blade form for external forms (left), internal forms (centre) and external and internal forms (right)

Through a special sonotrode design, the radius can be embossed directly following separation. For this purpose, the ultrasonically heated plastic is transformed at the separating edge.

In addition, the shape of the anvil or sonotrodes makes it possible to combine ultrasonic punching and welding, so that thermoplastics can also be welded or sealed during the separation process.

Ultrasonic punching is also very similar to ultrasonic welding in its process characteristics. Compared with other punching or separating technologies, the patented ultrasonic punching system essentially exhibits the following characteristics and advantages:

  • An ultrasonic-assisted punching stamp reduces punching force
  • No crazing for fluff formation on the punching surface
  • Decoupled, constant, radial embossing, irrespective of the material thickness
  • Visually clean punching of painted and unpainted plastics
  • No subsequent change as a result of punching plastics that have already been painted
  • Paint drawn in during radial embossing
  • Facility to combine welding and punching jobs, e.g. for sealing and separating packaging
  • Integration of ultrasonic punching technology into deep-draw packaging processes


As the developer of the technology and the market leader in ultrasonic punching, SONOTRONIC employs the technology in standard and special machines for a wide range of applications in various industrial sectors. The automotive industry in particular is one that benefits from the innovation. For example, the openings for parking sensors or headlamp cleaning systems with radial embossing can be fitted directly into the ready painted bumpers to provide visually outstanding quality.

Combining ultrasonic punching and welding opens up new possibilities in the packaging industry. Packaging can be sealed and separated by ultrasound in one process – even through liquids or wet contents. In addition, other sectors, such as the textile industry, domestic appliances, electronics and electro-technical industries, or medical engineering also avail themselves of the benefits of ultrasonic punching for appropriate applications.