A year of superlatives is drawing to a close. But even in the last days of 2022, SECO still breaks a record: Our acoustic fitting material team produces the 1000th batch of our unique, in-house material. This is used to couple the vibrations of the piezoceramics to air. Never before has the number of batches produced within one year been in four digits. Congratulations on a super achievement and thank you for your tireless efforts during this busy year.
Why does the ultrasonic transducer need an acoustic fitting material?
The acoustic matching material plays a crucial role in the efficient transmission of ultrasonic waves between an ultrasonic transducer and the air. Air has a low acoustic impedance, while the ultrasonic transducer usually has a much higher impedance. Therefore, the direct transmission of sound energy is inefficient. This leads to considerable reflections at the interface between the transducer and the air. This means that only a small proportion of the sound energy actually reaches the air. The acoustic matching material is used to bridge this impedance difference and optimally transmit the sound energy.
Properties and mode of operation:
A good acoustic matching material must have an acoustic impedance between that of the ultrasonic transducer and the air. This reduces reflections at the interface and maximizes the transmission of sound energy. Materials such as porous polymers, special foams or gel-coated membranes are often used. They have a relatively low acoustic impedance. At the same time, they are flexible enough to adapt well to the surface of the ultrasonic transducer.
Application in practice:
In practice, the fitting material is often applied directly to the surface of the ultrasonic transducer in the form of a thin layer. This layer ensures that the transducer transmits the sound efficiently into the air. And it also radiates it evenly into the environment. This is particularly important in applications such as airborne ultrasound diagnostics, where precise measurements are required in gaseous media.
Significance for ultrasonic technology:
Without a suitable acoustic matching material, the efficiency of ultrasonic transducers in air would be severely limited. The correct selection and application of this material is therefore crucial to the success of many ultrasonic applications that rely on the transmission of sound waves in gaseous media. This applies to both industrial and medical applications where precise and efficient sound transmission is essential.
At SECO, we produce this acoustic fitting material according to our own tried and tested recipe
To achieve the best possible results, we use a particularly light, pressure-resistant epoxy filled with hollow glass beads. Compared to the products of external suppliers, it is subject to only minimal fluctuations.