Home/Benefits of plastic welding


In contrast to many ways of joining thermoplastics, there are several advantages to be highlighted when using ultrasonic technology: faster, safer, cleaner, more efficient, more environmentally friendly, more precise, more transparent, and much more.

It quickly becomes clear that ultrasonic joining technology is an asset for any industry – even in demanding sectors such as medical technology, food & packaging, automotive or hygiene products.


Ultrasonic welded compounds represent an optimal and efficient solution for joining thermoplastics.

Features such as energy efficiency, tightness and high reproducibility are indispensable here, especially for the above-mentioned industries. The prerequisite is always optimally designed joining parts (by the customer).

Under the effect of force, longitudinal vibrations with frequencies of 20-40 kHz and welding amplitudes of 10-60 μm are introduced into the plastic parts. The plastic melts and the two parts joining together. A material-locking connection is created in the weld seam.

Very good results can be achieved due to the optimal design of the components.

The energy focusing achieved by the intelligent component design is the key to success here.

The joined parts can then be immediately processed further for the coming process steps.

Read more details about the medical technology sector here..


Longitudinal ultrasonic welding process

The process is based on a pulsating, very fast, change in length of the sonotrode in the range of 15 to 60 µm. The ultrasonic energy is thus introduced into the component at a 90° angle to the sonotrode contact surface. The energy then focuses in the optimally designed welding plane and causes the thermoplastic material to melt. After the melt cools, a solid joint is then formed.

Most commonly used process in the field of ultrasonic welding of thermoplastics.

Torsional ultrasonic welding process

Also in this process, the sonotrode is placed on the component at a 90° angle. The process is based on a pulsating, very fast rotational movement in the range of 15 to 60 µm. As a result, the parts to be joined make a relative movement to each other. In the correspondingly designed welding plane, the material is made to melt. After the melt has cooled, a solid joint is then formed.

The advantage of this technique is the lower stress on the parts due to the rotational energy input. The process is therefore suitable for sensitive joining parts, films and membranes.


+ Very short process times
+ Low thermal impact on the component and the surrounding area due to welding tools close to ambient temperature
+ Low energy consumption during welding and thus high efficiency
+ No solvents and additives necessary (pure recycling)
+ Constant, reproducible welding results are made possible via a wide range of parameterization options
+ Different thermoplastic materials can be partially welded together
+ The welding tools do not heat up, thus reducing setup and teardown times. Warm-up and cool-down times are eliminated and the tools can be changed quickly.
+ No risk of injury from hot machine parts
+ Very good integrability into automation systems
+ Possibility of intelligent networking and self-control – Industry 4.0


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