Have you ever wondered what might be the most successful 3D printed product by now? It’s not jewelry or prototypes – no, hearing aids have been the moneymakers in 3D printing since almost a decade. Find out more here!
Hearing Aids – the Myth of a Niche Market
3D printing has gained ground in most parts of the medical device market. It has simplified the production of customized medical devices and helped to shorten the production costs.The general public is not familiar with the fact that in 2014 10m pairs of 3D printed hearing aids have been sold (Phil Reeves, Econolyst). Therefore, the chance is very high, if you are wearing a hearing aid, that your item is already 3D printed.
The history of 3D printed hearing aids is not a recent one, but started in the 1990s and was widely known as ‘additive manufactured hearing aids’. The main target group for these devices are senior people and patients who have to rely on hearing aids to manage their daily life.
The production of hearing aids seems to be a niche market. Why?
The mass media and lots of economic analysts, which have been analyzing the demand of the 3D printing market for several years now, very rarely mention the additive manufacturing of hearing devices, although it represents an excellent opportunity for additive manufacturing as every ear is uniquely shaped. Therefore, 3D printing is predestinated for the production of customized medical devices; from its beginning to the final product. The Swiss company Sonova (Staefa, Switzerland) was one of the first companies worldwide that started to use the 3D printing technology for producing its hearing aid devices in the early 2000s. Besides the digital production of shells for custom in-the-ear hearing aids (ITE), Sonova started to produce custom earpieces for behind-the-ea (BTE) and receiver-in-canal, i.e. invisible (IIC) hearing aids.
From Nothing to a Hearing Aid – The Technology
How does the 3D printing of hearing aids work?
- A silicone impression of the ear canal is needed (still taken by hand)
- The scanning of the impression into the computer is processed by using laser technology
- Further processing is carried out digitally on-screen
- CAD file for printing is created on the computer
- File is stored in a central database and transmitted to a computer
- Layer by layer printing with light-curing acrylic resin
The Printer Technology
Can any 3D printer be used for the production of hearing aids? The answer is no. There are special 3D printers which are custom-made for the hearing aid market. One company that offers this kind of printers is Envision Tec, founded in Marl, Germany, 2002. Their Perfactory 4DSPXL (Digital Shell Printer) is one of the largest printers for producing hearing aids. It works with a layer-by-layer method and a DLP (Direct Light Projection) technology to create models from a plain basin of resin with low acquisition costs. This printer has some special features, e.g. it can be used for large scale production due to its large build area and high resolution. Furthermore, resolutions down to 42 µm in the X and Y are possible. You can achieve micromechanics as little as 15 µm in Z (material dependent). The production time of a tray of hearing aid shells can be estimated around 2-3 hours, respectively 1-2 with a high-speed module as the DLP process cures all parts simultaneously.
Nevertheless, this printer requires some delicate post processing work once a print has finished. The support structures have to be removed by hand, making the last step of each job quite delicate and time consuming. Therefore, the 3D printing of hearing aids still needs a set of skilled people.
As the Medtech branch, and here especially devices, get more and more important to the 3D printing industry, we are always looking for new topics we can give an insight on. If you have any ideas, or you have the impression we forgot an important topic, please comment here or message us on FB or twitter
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