Doors on Airbus’ massive A380
Berlin, Germany-based Holmberg GmbH develops and produces electro-acoustic devices used by Airbus and many other airplane manufacturers, including sound transducers, for which the aerospace industry requires comprehensive certification of reliability and lifespan. Piezo sound transducers for airplane doors are subject to considerably higher quality requirements than conventional mass-produced commercial buzzers.
To meet the demanding requirements, Holmberg selected custom piezo ceramic discs manufactured by Physik Instrumente (PI) Ceramic, which
Sound transducers consist of two piezo disks glued to each other, a plastic membrane, and a waterproof case. When
“We obtain the two piezo disks which are already glued together. The piezo disks meet our high standards of quality and are distinguished by a very low tolerance to all piezoelectric parameters relevant for sonic performance, such as resonant frequency, electrical capacitance, and coupling coefficients,” explains Peter Köppel, technical director at Holmberg.
The vertically-integrated piezo sub-assemblies can be adapted to any original equipment manufacturers’ (OEM) application because all production steps from the raw material, geometric design, and assembly are performed within a single manufacturing facility.
Piezo transducers start as mixtures of different, finely ground materials. The PZT (lead zirconate titanate) mixtures are then baked in high-temperature ovens with different formulations optimized for individual applications.Physik Instrumente LP (PI)