In this episode, Steve Davis sits down with Michael Muchin, Business Director at Avery Dennison Medical, to explore the complexities of wearable medical devices and stick-to-skin adhesives. Michael shares insights into the human factors that influence adhesive performance (such as skin type, age, activity level, and placement on the body) and explains why there's no one-size-fits-all solution. The conversation covers misconceptions designers often have, the importance of testing, and how Avery Dennison guides design teams through early development with tailored sample kits and wear study protocols.
The episode also breaks down the construction of wearable adhesives, including the skin layer, tie layer, and overpatch materials. Michael defines key adhesive metrics like tack, shear, and peel, and explains how they influence design decisions based on device weight and placement. He emphasizes the role of the tie layer in bonding different materials and the need for customization depending on application requirements. Throughout the discussion, Michael highlights Avery Dennison’s collaborative approach to helping customers validate and scale their designs effectively.
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Conversation Overview
1. Introduction and Collaboration
- Steve welcomed Michael Muchin for an in-person episode, highlighting Avery Dennison Medical’s long-standing expertise in bonding medical products to the body.
- Michael described the evolving collaboration between material suppliers and converters, emphasizing the importance of working closely with OEMs to deliver effective wearable solutions.
2. Adhesive Design Misconceptions
- Michael explained that designers often underestimate the complexity of adhesive selection, assuming skin behaves like standard materials.
- He emphasized that each wearable application is unique, requiring tailored solutions and real-world testing rather than relying solely on lab data.
3. Wearable Construction Layers
- Michael broke down the typical wearable stack-up: skin adhesive, tie layer, and overpatch, each with distinct material and adhesive requirements.
- He highlighted the tie layer as a critical but often overlooked component, responsible for bonding the device to the skin adhesive and accommodating diverse surface energies.
4. Human Factors in Adhesion
- Michael discussed how skin type, age, oiliness, hair, and body placement all influence adhesive performance and design choices.
- He noted that designers are increasingly choosing body locations with better adhesion surfaces, such as the upper arm or chest, to improve reliability.
5. Adhesive Mechanics and Design Impact
- Michael defined tack, shear, and peel as key adhesive metrics, explaining how they affect bonding strength and device stability.
- He illustrated how balancing these forces is essential, especially when mounting heavier devices that require strong shear resistance without compromising comfort.
6. Design Journey and Support
- Michael outlined Avery Dennison’s approach to guiding design teams, starting with detailed questions and progressing through mock-up testing and wear studies.
- He shared that Avery offers internal testing and wear study protocols to help teams validate their designs
