This is how big Teltonika IoT Group is. The IoT group subsumes 5 subsidiary companies working in: Telematics (tracking hardware), Networks (professional networking equipment), Mobility (personal tracking, asset tracking and electric mobility) telemedicine (pulmonary ventilator and other healthcare devices) and EMS (manufacturing).
Teltonika Telemedic almost two years ago initiated an innovative smart watch development project in the telemedicine industry. Teltonika Telemedic developed a device that can detect continuous ECG levels and atrial fibrillation. A smartwatch now undergoes the final technical checks and certification procedures.
Clinical trials were carried out which delivered extraordinary results demonstrating high accuracy of ECG recording – 99,2% compared with in-hospital ECG holters. It indicates high precision to distinguish atrial fibrillation from other arrhythmias reaching 99,1 %, tested with more than 30 % of patients with frequent arrhythmias symptoms. The use of PPG in continuous monitoring of heart activity will allow detecting irregular heart rate in a timely manner even if there are no symptoms felt by the user. Thus, the smartwatch would detect asymptotic atrial fibrillation and prevent heart diseases if patients are diagnosed as early as possible.
The design form molding
To fit all of these technological features into a usual every-day smartwatch is quite a challenge both for designers and manufacturers.
“The conception of design is not a job that takes one day or a month to complete. It is way more than you can think of. It took us nearly half a year to develop the design that it is right now. We put a lot of thought into producing a unique design which would be intuitive to use.” – says Eimantas Ramunis, Product Owner at Teltonika Telemedic.
Many smartwatches in medical and consumer markets were compared and analysed, the flaws were determined to outperform competitors and stand out of the crowd. Teltonika design team came up with nearly five different designs. Thus, not surprisingly, it was even more difficult for the whole team to choose the best one not only from the design point of view but also from manufacturing.
The plastic case
A good designer knows that what looks and feels good does not always work out with technological aspects and might cause problems with manufacturability. To speak numbers – the watch will have six sensors contacting with human. From the manufacturability side, it means making slots, holes, fixtures and complex shapes to integrate all of the technology. Since the only option for making this product tangible is injection molding it also means that variety of inserts will be used to form these complex features and that the moldability optimization also should be implemented.
Micromolds℠ is driven by such challenges daily and that is what we love about on-demand molding business. We are proud to be chosen to fulfil “TeltoHeart” smartwatch prototyping phase needs from design optimization and consultation to actual physical prototypes.
“The company was contacted due to their flexibility and short lead times, also because their other manufactured products proved to be high-quality. We need a flexible and reliable partner that can produce on-demand quantities. They are the perfect partner as they own the injectors that warrant our initial quantities.”– says Eimantas Ramunis, Product Owner at Teltonika Telemedic.
Mold inserts made with metal 3D printers
The watch strap had to be mounted to the plastic case at a particular angle which made mold machining nearly impossible. Luckily, metal 3D printing technology could be used for that. Metal 3D printing technology is based on laser power which binds small metal particles in requires geometry. Layer by layer 3D printer made the inserts which were successfully installed inside the molds. Not only have 3D printed inserts been used but also the sensors and metal connectors made and designed by Teltonika Telemedic team.
It was quite a challenge to fit them all in such a tiny plastic case which meant placing every insert inside the mold at specific positions with an extra high precision to avoid any defects like flashes or unwanted weld lines.
The overmolded elastomeric watch strap
Rubber, silicone and elastomer – all three different chemical materials but very similar for a regular user. When looking for material for a watch strap two main challenges arise immediately. The first being the resistance to wear and the second being the tackiness. Not only the material will have to maintain its form while being twisted, bended and stretched but also not to collect dust and feel comfortable.
“Originally, we wanted to explore ideas using silicon bands, but silicon does not provide the durability and properties that are offered by TPUs” – says Jostautas Petrusevičius, Hardware Engineer at Teltonika Telemedic.
Huge amount of TPEs’ combinations was tried to obtain the desired feel on the skin. The strap also had to be hypoallergenic and withstand sterilization even with corrosive liquids like isopropyl alcohol.
When it seemed that the right material has been found there were always one more thing to remember - “TeltoHeart” smartwatch strap will have an integrated sensor. Such integration is one of its kind in the whole smartwatch industry and this is one of the reasons why Teltonika Telemedic team has also consulted with our company. Such feature demanded an extraordinary technology. How to insert such a sensor in a flexible elastomer strap which would resist fatigue and other environmental harsh conditions over time. Elastomer overmolding came as perfect solution.
While overmolding itself is not something new we have been doing, in this case we had to overmold the flexible (floating) wire inside the strap. Even though injection pressures are not high but it can still deflect the wire inside the strap which would result in wire being not fully overmolded. Despite this difficult challenge our team succeeded in a uniform wire overmolding.
“We are really satisfied with Micromolds ℠ services. The company offered fast and responsive technical support. It helped us to save time and expenses on expensive tooling for mass production. We could see and test possible problems before mass production and eliminate them.”– Eimantas Ramunis, Product Owner at Teltonika Telemedic.
The quote above summarizes it all. We are so happy to share this story which once again proves that our hard work pays off. We can deliver results and we truly help companies to innovate and this is the biggest reward we can get.