Hearing Aid Manufacturing: Ear Trumpets to ABB YuMi

A modern hearing aid packs a microphone, a processor, a battery and a receiver into a shell that has to fit one person's ear canal. Hearing aid manufacturing has therefore always been small, fiddly work, done first by instrument makers and later by technicians at benches with tweezers and microscopes. This post follows that work from ear trumpets and the first electric aids to 3D printed shells, then looks at how hearing aid makers such as Starkey and Oticon use automation today, where ABB's small-parts robots like YuMi could fit, and what still makes these tiny devices hard to build by machine.

A spread of modern behind-the-ear and in-the-ear hearing aids, batteries and ear tips. Photo: Vilma Liella / Wikimedia Commons (CC BY-SA 2.0)

How ear trumpets became electric hearing aids

The first hearing aids were ear trumpets, made from the 17th century onwards in tin, silver and other metals. They needed no power at all: a wide mouth gathered sound and a narrow tube carried it into the ear. Instrument makers built them one at a time, and some Victorian ones were dressed in black silk and lace for mourning. Electricity changed the job at the end of the 19th century. Around 1895, the American inventor Miller Reese Hutchison created the akouphone, usually counted as the first electric hearing aid.

A Victorian ear trumpet wrapped in black silk and lace for mourning. Photo: Wellcome Collection via Wikimedia Commons (CC BY 4.0)

The next step was the vacuum tube. In 1920 Earl C. Hanson patented the Vactuphone, the first vacuum tube hearing aid to be produced commercially, and Western Electric put it on the market in October 1921. Tube aids worked, but they needed big batteries and a body-worn case. One example of these bulky sets is the Medresco, a portable aid designed by Britain's Medical Research Council and made by Remploy, with an ear piece, a microphone and large Ministry of Health batteries carried in a leather pouch. People wired, soldered and tested these sets by hand in small workshops.

The Medresco portable hearing aid, designed by the Medical Research Council and made by Remploy. Photo: Wellcome Collection via Wikimedia Commons (CC BY 4.0)

The transistor, invented in 1948, suited hearing aids so well that body-worn boxes shrank into units that sat behind the ear during the 1950s. Custom in-the-ear aids still needed a shell shaped to each customer, and for decades that meant a technician casting it from an ear impression and grinding it to fit. Around 2000, manufacturers moved this step to the computer. Phonak filed a patent in October 2000 on methods for the rapid production of hearing aid shells, and Siemens Hearing Instruments filed one in 2001 for a shell made by rapid prototyping. Today the digitally modelled shell is usually printed by stereolithography.

Two Zenith Diplomat transistor behind-the-ear hearing aids from about 1956 and 1959. Photo: Joe Haupt / Wikimedia Commons (CC BY-SA 2.0)

Inside today's hearing aid factories

Hearing aids now carry AI chips, health sensors and Bluetooth, and that is changing how they are built. In a September 2026 interview with Chief Executive, Starkey CEO Brandon Sawalich said the Minnesota company has made many investments in automation, especially in quality and distribution. He said Starkey moved a major manufacturing site to a new facility in under 60 hours without disrupting business, opened a new APAC facility and a European distribution center, and plans to bring more AI into its manufacturing processes. Starkey has more than 5,000 employees and facilities in over 29 countries, according to the interview.

A resin 3D printer in a dental lab; custom hearing aid shells are printed with the same stereolithography method. Photo: Stutamad / Wikimedia Commons (CC BY-SA 4.0)

Robots are already in some of these plants, mostly at the smallest steps. Oticon, the Danish maker, had used two- and three-axis robots for about ten years, Universal Robots reports, but its parts became too small for them. It now runs a six-axis UR5 cobot on an injection moulding machine that sucks up to four plastic parts at a time out of the mould, some only a millimetre in size, in cycles of four to seven seconds. In Singapore, WS Audiology's operation produces more than half of all the hearing aids the company sells worldwide, according to the Singapore Economic Development Board.

A pair of Oticon receiver-in-the-ear hearing aids. Photo: ikesters / Wikimedia Commons (CC BY-SA 2.0)

ABB has not published a hearing aid customer, so what follows describes how its robots could fit. The dual-arm YuMi IRB 14000 was built for small-parts assembly next to people, with two seven-axis arms that each handle about 0.5 kg, and the single-arm YuMi IRB 14050 puts one of those arms on a compact station. A YuMi could, in principle, place receivers and batteries into housings, run acoustic tests or load shells into printers. ABB already shows YuMi on similar work in electronics, and our post on medical device assembly covers related cases.

ABB YuMi assembling small parts beside a lab worker. Photo: ABB

What comes next for hearing aid production

Since 17 October 2022, adults in the United States with perceived mild to moderate hearing loss have been able to buy over-the-counter hearing aids without a prescription, which put hearing aids on pharmacy shelves. For people at home that opens a cheaper, simpler way to try a hearing aid. For factories it points to higher volumes of standard models at lower prices, which is the kind of work where automated assembly starts to beat hand benches.

Senator Elizabeth Warren holds a boxed over-the-counter hearing aid at a Washington, D.C. Walgreens on 19 October 2022. Photo: US Department of Health and Human Services via Wikimedia Commons (public domain)

Custom devices will not go away, so the factory of the next few years will probably mix standard and custom work. Shells will keep coming out of stereolithography printers, while cobots move parts between printers, curing stations and test rigs. Single-arm YuMi cells are compact enough to slot into a line built around people, and they can be programmed without code using Wizard on the FlexPendant. Lines like this are usually laid out and tested first in RobotStudio before anything is installed.

A single-arm YuMi IRB 14050 in its cell on GE Healthcare's prototype line in Helsinki. Photo: ABB

The open problems are mostly about size and change. Parts a millimetre across need grippers, vision and feeders that most robot cells were never designed for, and product families change often as new chips arrive. Cost is a problem for smaller makers, since a robot cell has to earn its price over many units. Skills matter too: technicians who built aids by hand now need to program and maintain cells. Starkey's plans for more AI on the factory floor suggest the big makers think the effort is worth it.

Programming a single-arm YuMi with Wizard on the FlexPendant. Photo: ABB

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