About Ultrasonic Welding

What is ultrasound?

Ultrasound is mechanical oscillation with a frequency between 20 kHz and 10 GHz. This means that it is inaudible to humans, as we can only hear sounds between 16 Hz and 20 kHz.

Ultrasound is generated using high-frequency electrical energy, which is then converted to mechanical energy. As a form of mechanical oscillation, the sound travels through the air and other media at a defined speed as a wave of pressure. Frequency is a measure used to express how often the cycles of a periodic process – like the contracting and deforming motions of our ultrasonic tools – recur. One hertz is equivalent to one oscillation per second.

How does the ultrasonic welding and cutting process work?

To weld and cut with ultrasound, we use energy and convert it to sound waves to melt the plastic. The operating frequency varies depending on the application. As Rinco covers a full spectrum of frequencies between 20 and 70 kHz, we can provide perfectly tailored ultrasonic solutions for any welding or cutting application.

How does mains power/energy get converted into ultrasound?

To convert electrical energy (electricity) into mechanical oscillations (ultrasound), you need a generator and a converter. The generator first converts the 200/230 V mains voltage and 50/60 Hz (socket) energy into a HF voltage with a defined frequency of at least 20 kHz. Depending on the application, the frequency can be anywhere between 20 and 70 kHz.

The downstream converter turns the high-frequency electrical energy into mechanical oscillation. Inside the converter, there are a number of piezo discs, which respond to the electrical energy by alternately contracting and deforming. This movement causes the converter to oscillate. The resulting ultrasound is emitted at an amplitude and frequency set by the generator, which are transmitted by the converter to the downstream booster and the sonotrode/work horn.

The sonotrode/work horn is the actual welding or cutting tool that makes contact with the workpiece.  Often, the converter, booster and sonotrode are collectively referred to as the oscillation system or vibratory stack. These components must be acoustically fine-tuned to work together efficiently.


If your business involves the sealing packaging, welding plastic moulded parts, punching out components or cutting textiles or food products, then ultrasound could be the perfect addition to your production process. Ultrasonic technology is fast, very energy-efficient and economical with materials, guaranteeing speed, precision and efficiency.

We will explain how ultrasonic technology works, how our machines are designed and what you can do with them – all in a way that’s easy to understand.  We may just have the solution you need to optimise your production processes.