While the likes of Adidas, New Balance and Under Armour duke it out in the attempt to bring customised wearables to the masses, boasting about the possibility of 3D printing 100,000 pairs of sneakers next year, hearing aid manufacturer Sonova can look at those figures and grin.
Last year alone the company 3D printed over 1,000,000 unique custom pieces installed in millions of ears globally. Sonova may not be as well known as the sportswear giants but its two leading brands, Phonak and Unitron, are considered to be the best of the best when it comes to ‘in the ear’ custom hearing aids. In terms of market share, Sonova is very much the number one hearing aid manufacturer.
A desire to be at the vanguard of hearing aid development sets Sonova apart from its competitors. Sonova’s early adoption of 3D printing and in particular EnvisionTEC’s DLP machinery over a decade ago left others trailing in the wake, eager to catch up with its lean manufacturing process.
“Together with EnvisionTEC, we collaborated quite intensively to bring this cutting-edge DLP technology into an on-demand manufacturing,” said Mujo Bogaljevic, VP of Operations, Sonova US. “We have completely transformed the way custom hearing aids are made today.”
The collaboration went far beyond a typical vendor-customer relationship with Sonova pushing EnvisionTEC’s development in materials science. Sonova required biocompatible materials, safe for long-term use in the ear without causing irritation or discomfort. In turn, EnvisionTEC’s process inspired and enabled Sonova to switch to a finely-tuned digital manufacturing process.
Phonak hearing aids 3D printed shell removal
3D printing has eliminated a traditional handcrafting process for custom hearing aids that weren’t always up to scratch. The tolerances for a perfect fit in the ear canal are so tight that a fraction of a millimeter in either direction can lead to severe discomfort. Today’s 3D printed shells are a precise replica of the ear impression taken by a hearing healthcare professional resulting in an excellent fit with more room for microelectronics.
“It’s really important that we accurately reproduce that impression in order to make sure that we wind up with a very comfortable fit for the patient and good retention in their ear,” said Bill Lesiecki, Director of Business Services at Sonova US. “There are ears that are very challenging. 3D printing is made for that kind of customisation, so it can really have an impact.”
At Sonova’s Aurora Operations and Distribution Center in Illinois over 20 EnvisionTEC Perfactory machines churn out hundreds of hearing aid shells an hour. Sonova uses over 100 EnvisionTEC machines globally. Two shifts of 500 staff clean, assemble and qualify the hearing aids ready to make people’s lives better, and for Mujo Bogaljevic that’s the real beauty of what Sonova does:
“The patient feels better; they’re getting smaller hearing aids that fit better, that are being retained in the ear better, that last longer, that have a cosmetic appearance that is acceptable to them. It is a great cause to help people improve their hearing, and that is what we do, we help people hear better and live life without limitations.”
The next generation of hearing aid manufacturing
Sonova may well have perfected a process using EnvisionTEC’s DLP technology, but CEO Al Siblani believes that its latest technological breakthrough, Continuous Digital Light Manufacturing (cDLM) offers substantial improvements when it comes to hearing aid devices.
Because cDLM technology no longer has the peeling step between layers required in DLP, parts can be printed faster, smoother and, crucially for the hearing aid industry, more transparent.
The two existing cDLM platforms can build in 25-micron Z-layer thickness in the same time it takes DLP technology to print parts with 100- micron layers. This added accuracy without added time means cDLM technology delivers uniform curing in Z and a refraction-free edge for transparent parts without the need to clear coat.
The parts in the above photograph were printed in the same material and cleaned with Isopropyl Alcohol. They were not polished or lacquered. The two parts in the centre were printed with cDLM technology, while the parts on the outer edge were printed with DLP technology.
The journey of a 3D printed hearing aid
