Freudenberg - Innovating Together

Enabling Digitalization of Smart Medical Devices

Freudenberg Medical develops electrically conductive silicone and encapsulates electronic components to deliver custom applications

The increasing digitalization of medical devices is a global trend. The use of medical silicone is also playing an increasingly important role here. Two main approaches can be distinguished:

Encapsulation of electronic components with silicone 

So-called wearables such as smart watches, fitness trackers and heart rate monitors are worn directly on the body and monitor vital signs. Silicone insulates the electronic components and sensors, protecting them from dirt, water and sweat. This ensures reliable operation and durability.

Electrically conductive silicone

By combining silicone and conductive fillers, electrical currents can be conducted, and specific parts of the body can be stimulated in a targeted manner. Areas of application include neurostimulation for pain treatment or targeted training of specific muscle groups.

Jump directly to successful customer projects: 

Materials and process knowledge

The manufacture of such materials requires not only medical expertise but also a high level of materials development and tooling competence. Freudenberg Medical has many years of manufacturing experience in the field of biocompatible silicones and a high level of expertise in electrical functionalization. Furthermore, the company can specifically overmold electronic components with silicone.

Freudenberg Medical's core competencies include:

  • Production of electrically conductive silicone
  • Overmolding of electronic components with silicone
  • Joining of silicones with different degrees of hardness
  • Development of manufacturing and mold technologies, e.g., high-precision high consistency silicone injection molding
  • Performance of quality tests on behalf of customers


Successful Customer Projects 

Monitoring Belt for Premature Babies

Freudenberg Medical supports Dutch start-up Bambi Medical with innovative silicone solution
The Dutch start-up Bambi Medical has developed the Bambi Belt, an innovative monitoring system for premature babies. The Bambi Belt replaces cumbersome cables and electrodes when monitoring premature babies with a skin-friendly silicone belt with integrated electronic sensors. The soft belt can be put on and taken off without pain or discomfort to the baby, and the sensors integrated into the belt record the baby's vital functions via the skin.

Data transmission by radio instead of cables

The recorded data is transmitted to the monitoring device by radiofrequency. Interfering cables are eliminated, and parents can hold their child normally and make physical contact. This promotes the baby's mental development. Disturbing adhesive electrodes are also eliminated. This is important for the particularly sensitive skin of premature babies to prevent wounds and infections.

Freudenberg Medical is supporting Bambi Medical in the manufacture of the belt with material and process expertise. The Bambi Belt uses platinum-cured, biocompatible silicones of various degrees of hardness, other materials, and sensors. Thorough material analysis and numerous tests were required to ensure that the various materials are compatible with each other and achieve the desired physical properties.

Customer relies on expertise from Freudenberg Medical

The result is a flexible conductor track coated with various silicones and incorporating sensors, which both adheres well to the skin and can be easily removed. The velvety surface texture is achieved without additional coating, further reducing material and process steps.

The Bambi Belt team is convinced by the belt and the collaboration with Freudenberg Medical: "It is a complex product that did not exist on the market before," says Fabio Bambang Oetomo, CEO and co-founder of Bambi Medical and son of inventor Professor Bambang Oetomo. "The technical challenge was therefore high, but already after developing the first samples we knew we had made the right choice."


"The main challenge was the processing of the materials. To ensure that the belt is as comfortable to wear as possible, we have to process particularly soft materials with a well-thought-out design, which requires extensive experience in injection molding."

Daniel Kaltbeitzel, Head of Engineering at Freudenberg Medical in Kaiserslautern, Germany

The advantages at a glance:

  • Bambi Belt is made of a particularly soft and biocompatible material. It adheres to the skin while being easy to remove.
  • The velvety texture of the material is achieved without an additional coating step thanks to Freudenberg Medical's material expertise.
  • Vital functions are transmitted wirelessly, making cables superfluous.
  • The absence of cables facilitates bonding between parents and baby.

Neuromuscular Electrical Stimulation against Sleep Apnea

Freudenberg Medical manufactures medical components made of electrically conductive silicone for innovative neuromuscular tongue training device from Signifier Medical Technologies

Many people worldwide suffer from mild obstructive sleep apnea. In addition to reduced sleep quality, sleep apnea is associated with other risks, including high blood pressure and Alzheimer's disease. Among the most common causes of this breathing disorder during sleep is slackened tissue in the nose and throat. However, strengthening the tongue muscle can reduce the problem.

Idea meets materials and process expertise

London-based medical technology company Signifier Medical Technologies is using this insight for its tongue training with the eXciteOSA®. The device is worn in the mouth for 20 minutes a day, where it stimulates the tongue muscle with minimal electric shocks via a smartphone app. The mouthpiece for the eXciteOSA® is manufactured at Freudenberg Medical´s facility in Germany.

The material for the mouthpiece consists of an electrically conductive silicone that Freudenberg has further developed especially for Signifier Medical Technologies. Existing solutions such as graphite fillers were ruled out for a medical mouthpiece due to poor aesthetics, among other reasons. Established modifications with carbon nanotubes (CNTs) also failed to meet the requirements because they could not ensure the necessary conductivity during processing due to high shear forces. For the eXciteOSA®, fine metallic fillers already coated with another metal are mixed into liquid silicone in a specific ratio. When cured, this produces small, conductive silicone pads. Four of these are then inserted per mouthpiece into a lower shell of liquid silicone. Finally, a top shell is added, and the product is overmolded with silicone. Freudenberg Medical tests the electrical functionality of each individual mouthpiece.

High wearing comfort for more well-being and health

"Saliva, temperatures, mouth movements or cleaning agents - they all have an impact on the long-term reliability of the mouthpiece," says Daniel Kaltbeitzel, Head of Engineering at Freudenberg Medical´s German facility. "This has necessitated extensive material testing and analysis to ensure the product's lasting functionality."

In addition, all the tools used to manufacture the mouthpiece first had to be specially developed by Freudenberg Medical. "The platinum-cured electrically conductive silicone is extremely viscous and difficult to process. Standard manufacturing processes and tools are not optimized for these special needs. So, we used our knowledge of process and automation technology to be able to implement the customer's wishes with specially fabricated molds. Our internal Freudenberg business network helped us in this," Kaltbeitzel continued.


"The material we developed is not only completely harmless to health - it is also medically approved and guarantees patients a high level of wearing comfort in the mouth, thus contributing to the well-being and health of end customers."

Dr. Kai Opdenwinkel, General Manager of Freudenberg Medical in Kaiserslautern, Germany


Freudenberg Medical's expertise in the manufacture of the eXciteOSA®:

  • Material expertise: Freudenberg Medical further developed a silicone to meet customer requirements.
  • Fine metallic fillers are coated and incorporated into the silicone base material in the correct ratio.
  • Making silicone conductive: The resulting silicone pads are electrically conductive and are inserted between the lower and upper shells and then overmolded with biocompatible silicone.
  • Production is carried out in clean room manufacturing under the highest quality standards.
  • The mold and production concept was developed with process and automation know-how from Freudenberg Medical according to customer requirements.
  • In-house testing of the electrical functionality of each individual mouthpiece.


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