EP21LSCL-2Med: Encapsulating Wearable Sensors Using a Pre-Mixed Two-Part Epoxy Product

The growing field of wearable medical technology relies heavily on miniaturized sensors capable of providing accurate and continuous physiological data. Ensuring the long-term reliability and performance of these sensors — often subjected to demanding conditions including physical stress, thermal fluctuations, and exposure to bodily fluids hinges on robust manufacturing processes. A critical aspect of this manufacturing involves the precise application of biocompatible adhesives for encapsulating delicate sensor components.

This case study examines the selection and implementation of a non-cytotoxic adhesive chosen for its ability to encapsulate sensors from harsh environmental factors such as humidity, dust, and mechanical impact. It will also explore the automated dispensing equipment utilized to achieve the accuracy and consistency required for the scalable production of these advanced medical devices. To ensure that the manufacturing process was optimized, the combined expertise of fluid dispensing leader Nordson EFD and specialty adhesive manufacturer Master Bond were critical for producing high-quality wearable sensors.

Material and Dispensing Requirements

The product selected for this encapsulation process needed to meet several key requirements to ensure its effectiveness and compatibility with this wearable sensor. The sensor required a low-viscosity epoxy with capillary flow characteristics that enabled easy and precise dispensing. It was critical that the material flowed easily around the sensor components and filled intricate spaces without leaving voids.

The material also needed to be curable below 80°C, to prevent heat-sensitive electronic components from being damaged. Optical clarity was another key requirement. Additionally, a non-cytotoxic encapsulant was a must to ensure safe use when it encountered the skin or the human body. Finally, the dispensing process had to be automated, capable of dispensing approximately 3cc of the material per sensor consistently.

To read about the materials, packaging, equipment and dispensing solutions, please download the full case study.

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