Besides its individual geometry, the ear canal has hard and soft tissue regions. To improve the wearing comfort of mold fittings for hearing aids, so-called earmolds, the hardness of the material must be locally adjustable.
To print earmolds with hard and soft regions, the Production and Systems Technology Department at the LZH is developing a new 3D printing process that is based on a layer-by-layer spraying of the material. If two nozzles are used with polymers of different hardness degrees, a hardness of between 55 and 75 ShoreD can be achieved.
The research works are part of the project "3D-PolySPRINT – Additive Manufacturing of Customized Hearing Acoustic Transducers Made of Multi-Material Systems", which is funded by the Federal Ministry of Education and Research. Project partner are: Sennheiser electronic GmbH Co. KG, KIND Hörgeräte GmbH Co. KG, OptoMedical Technologies GmbH, Materialize GmbH, Dreve ProDiMed GmbH, LPKF Laser & Electronics AG, microTEC Gesellschaft für Mikrotechnologie mbH and the Laser Zentrum Hannover e.V. (LZH).