As a leading provider of ultrasonic welding equipment and a leader in plastic joining, we have the answers to all your ultrasonic welding questions.

What is ultrasonic welding?

Ultrasonic welding is a solid-state joining process that uses high-frequency ultrasonic acoustic vibrations. These vibrations are applied locally to workpieces that are held together under pressure.

What types of materials can be ultrasonically welded?

Ultrasonic welding is used to join thermoplastics that are soft and rigid and thermoplastic composites. In addition, it can be used to join metals like aluminium, brass, copper, most precious metals, and nickel alloys. The method can also be used to join dissimilar metals.

Is ultrasonic welding waterproof?

Ultrasonic welding does not produce naturally waterproof or airtight joins for products like water tanks, coffee pots, vacuum cleaner casings, etc. However, water or airtightness requirements can be met with proper positioning of the upper and lower plastic shells to be joined, weld line structure, wall thickness, materials, and ultrasonic frequency and power.

Is ultrasonic welding safe?

Ultrasonic welding is safer than many traditional welding methods because it does not require high temperatures or produce fumes. In addition, because it is highly targeted, this technique poses fewer risks that may result from excess electrical energy.

Is heat generated during ultrasonic welding?

Ultrasonic welding generates low amplitude mechanical vibrations using high-frequency ultrasonic energy. These vibrations generate heat where the parts being welded come together. While this heat is sufficient to melt thermoplastic materials, it is insufficient to melt the metals being joined.

What is the highest frequency that can be used in ultrasonic welding?

Ultrasonic welding has a maximum frequency of 70 kHz. The lowest frequency used is 20 kHz, which is barely audible to humans. Higher frequencies can only be perceived as vibrations.

What are the advantages of ultrasonic welding?

In plastic welding, internal heat generation causes less material to be heated, resulting in a smaller heat-affected zone and a lower chance of deformation. In addition, ultrasonic welding produces extremely fast cycle times, typically less than a second.

In metal welding, the metal does not melt during the solid-state process. Instead, it softens to the point where it can be pushed together, resulting in improved strength retention. And in addition to fast cycle times, ultrasonic welding offers greater precision in heating control than most other metal welding processes.

What is a sonotrode?

Sonotrodes are ultrasonic welding tools that vibrate when high-frequency mechanical oscillations are applied. They are designed using the Finite Element Method (FEM), which ensures optimal oscillation behaviour and longevity.

What is the function of sonotrode?

A sonotrode is used in ultrasonic machining, welding, and mixing and generates ultrasonic vibrations that it transfers to a gas, liquid, solid, or tissue. A sonotrode is typically made of a stack of piezoelectric transducers connected by a tapering metal rod.

What is a booster in ultrasonic welding?

Boosters, also known as amplitude transformers, are an essential component of the resonant structure. They change the amplitude provided by the converter and send it to the sonotrode. The amplitude varies depending on the plastic weld component.

How does an ultrasonic booster work?

The ultrasonic booster modifies the transducer’s vibrational output and transfers ultrasonic energy to the horn. In general, the booster provides a method for mounting the ultrasonic stack to a support structure. The ultrasonic horn then makes contact with the load and delivers power to it.

How is a sonotrode fixed to a booster?

The sonotrode is mechanically attached to the ultrasonic stack’s booster. The final amplitude experienced at the sonotrode face, and thus the amplitude used to weld two metal materials, is determined by the shape of the sonotrode.

What is an ultrasonic welding horn?

Ultrasonic horns are a catch-all term for all ultrasonic transmitters and are an essential component of ultrasonic welding equipment. Its purpose is to couple the transducer’s ultrasonic waves into the object being processed. Because it will be transmitting ultrasonic waves, the welding horn must be in a resonant state, meaning its natural resonant frequency must match that of the transducer. Second, the amplitude should be uniform, and the shape of the welding horn’s end face should match the shape of the workpiece to be welded.

What is an ultrasonic generator?

The ultrasonic generator produces a sinusoidal or pulse signal with a specific frequency, which is the working frequency of the transducer. Ultrasonic equipment uses ultrasonic frequencies of 20 kHz, 25 kHz, 28 kHz, 33 kHz, 40 kHz, 60 kHz, and above 100 kHz.

What is an ultrasonic generator used for?

The ultrasonic generator’s function is to convert mains electricity into a high-frequency alternating current signal that is matched with the ultrasonic transducer to drive the ultrasonic transducer to work.

What does HF stand for in welding?

High frequency (HF) welding is the process of fusing materials together by applying a rapidly alternating electric field between two bars in the joint area. It is also known as radiofrequency (RF) or dielectric welding. High-frequency welding only works with thermoplastics with a high dielectric constant, which is determined by the geometry and dipole moment of the molecule.

In general, high-frequency welding is not recommended for polypropylene (PP), polyethylene (PE), polytetrafluoroethylene (PTFE), polycarbonate, or polystyrene. However, because of the impending restrictions on the use of polyvinyl chloride (PVC), a special grade of polyolefin has been developed that can be HF welded.

High-frequency welding is commonly used in the production of medical supplies, including protective clothing, gel- and foam-filled cushions, lumbar support, hydration reservoirs, medical air and water mattresses, and stretcher and bed covers. Other products manufactured through high-frequency welding include flexible storage tanks, inflatable life jackets, flexible ducting, bellows, curtains, conveyor belts, water weights, lifting bags, inflatable boats, life jackets, life rafts, and other buoyancy equipment.

What are barrier materials in welding?

Barrier or buffer materials thermally insulate the weld area, allowing a larger weld area for a given amount of radiofrequency power. Elephantidae, polyester film, or phenolic laminates with high dielectric properties are frequently used to line the base plates. They also keep the edge of a tear-seal electrode from making contact with the bottom plate and causing an arc.

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For all your ultrasonic welding equipment needs and repairs, get in touch with us today for more information and offers on our plastic joining equipment, services, and spares.


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