Industrial ultrasound technology

How ultrasonic welding works

Operation of ultrasound

Ultrasonic welding consists of a process of mechanical vibration at ultrasonic frequency where the contact zone between the sonotrode and the part to be welded undergoes local fusion.

The 50/60Hz mains frequency is transformed and amplified by the ultrasonic generator as an electrical signal and converted by the piezoelectric transducer into movement energy.

This energy supplied by the generator and applied to the acoustic assembly must be sufficient to overcome the inertial moments of the masses to be set in motion and the friction between the parts.

The advantages of advanced technology such as ultrasonic welding are numerous:

  • Very short welding cycles (from a few tenths of a second)
  • Absolute consistency of results
  • Very low energy consumption and only related to the welding phase
  • No filler material
  • The parts are aesthetically perfect, very durable and immediately ready for use.

Industrial applications of ultrasound

Energy directors in ultrasonic welding

In order to reduce the areas of friction between the parts, which make it difficult to initiate the melting process, it is advisable to create geometric protuberances on the parts themselves, known as energy directors, which allow the material to be melted over a relatively small area.

In order to choose the most suitable energy director geometry for your application, we list some examples below and in any case we are available to offer our experience and technical knowledge.

As the figures above show, a triangular section on the joint serves to concentrate the energy of the ultrasound so that the joint surface is rapidly dissolved.

Common joints that incorporate the use of an energy director include: butt joints, segmented joints and tongue and groove joints.

The above joints are recommended for hermetically sealed parts or for plastics that change rapidly from solid to molten state.

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