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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
Wearables or smart devices are worn directly on the body and monitor vital signs. Silicone insulates the electronic components and sensors, protecting them from dirt and water. This ensures reliable operation and durability.
Electrically conductive silicone
Although silicone by itself is an insulator but when combined with fillers it can be conductive and the body can be stimulated. 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
- Overmold and encapsulate electrical components with silicone
- Two-shot injection molding of silicones with different durometers
- Design for manufacturability, process & tool technologies
- Characterization of electrical properties
Successful Customer Projects
Monitoring Belt for Premature Babies
Freudenberg Medical supports 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 a tangle of cables and electrodes when monitoring premature babies with a skin-friendly silicone belt with integrated electronic sensors. The soft belt can be taken on and off without pain or discomfort to the baby, and the sensors integrated into the belt record the baby's vital functions.
Enabling wireless data transmission
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. Annoying adhesive electrodes are also eliminated. This is important for the particularly sensitive skin of premature babies to prevent wounds and infections.
Freudenberg Medical supports Bambi Medical in the manufacture of the belt with material and process expertise. The Bambi Belt uses platinum-cured, biocompatible silicones of various durometers, electrodes and sensors. Thorough material analysis and numerous tests were conducted to ensure compatibility of the various materials and to achieve the desired specifications and customer requirements.
Customer relies on expertise from Freudenberg Medical
The result is a flexible conductor track that is coated with various silicones and incorporates sensors, which adhere well to the skin and can be easily removed or changed. The velvety surface texture is achieved without an additional coating process, further reducing material and process steps.
The Bambi Medical team is pleased with the collaboration with Freudenberg Medical and convinced of the technical success of the belt. "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 high, but immediately after developing the first samples we knew we had made the right choice partnering with Freudenberg."
"The main challenge was processing the materials. To ensure that the belt was as comfortable to wear as possible, we selected a particularly soft material and an intricate design, which required 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 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 to Treat Sleep Apnea
Freudenberg Medical developed a conductive silicone compound for an 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 insufficient tissue strength in the nose and throat. However, building up the muscle tissue in the tongue 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 strengthens the tongue muscle with minimal electric shocks, monitored 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 compounded into liquid silicone in a proprietary ratio. When cured, this produces small, conductive silicone pads. Four of these pads are integrated into a lower shell of liquid silicone. Finally, a top shell is added, and the product is overmolded with silicone. Freudenberg Medical tests the quality assurance 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.
