Meeting Evolving Material Selection Criteria for Medical Enclosures

Material choices will vary depending on the manufacturing process and device characteristics and life expectancy.

Geoff Giordano

March 16, 2022

4 Min Read
pulse oximeter
Image courtesy of Alamy/Tony ALS

The use of medical devices is proliferating outside the traditional healthcare ecosystem, as sophisticated monitoring and diagnostic capabilities are applied in home-care settings and among aging populations. Medical devices help to ease the burden on healthcare systems by monitoring patients to detect emerging health issues. As demand for those devices — many of them wearable or implantable — continues to grow, the materials used to manufacture enclosures must keep pace with performance requirements.

Those vital material choices will be the subject of a panel discussion, The Importance of Material Selection when Designing Medical Enclosures, at Plastec West in Anaheim, CA, on April 12.

Material choices vary “depending on the process, the characteristics desired, and life expectancy needed,” said panelist Mark Denning, Medical Market Business Manager at Sekisui Kydex. Plastics typically used include ABS, PC, polyesters, and PVC alloys.

“For the exterior housing or enclosure of a medical device, materials must meet the basic principles of a UL rating applicable to the finished product, durability, and ability to meet other global regulatory standards,” Denning advised. “However, as the medical device market evolves, new attributes are escalating as priorities.” These include:

  • Sustainability. Are the products being manufactured in a responsible manner? Is there a plan for the product at the end of life?

  • Design freedom. How can a device be visually appealing with color, texture, and shape while meeting physical property needs?

  • Chemical resistance. Is the material chemically resistant to the aggressive reagents used to disinfect device surfaces so they don’t fail in the field? “The pandemic has heightened this need through awareness that devices get bathed in disinfectants,” Denning noted.

While medical devices can take several years to bring to market, Sekisui Kydex had the opportunity to participate in an accelerated life-saving program with thermoforming partner Plastique Art.

Mark Denning, Sekisui Kydex.

“Medical device needs during the COVID-19 pandemic did not allow for a long development process,” Denning explained. “The challenge was to provide material for enclosures of 10,000 CAE AIR1 mechanical ventilators for the Canadian government as quickly as possible. From initial concept to completion, the project took only eight months. It was moving to be part of such an impactful story, which couldn’t have come together without the collaboration of over 300 suppliers to save people’s lives,” said Denning.

Joining Denning in the panel discussion will be Michael Zettel, Senior Material Scientist-Compatibility for PDI R&D in Woodcliff Lake, NJ. Elaborating on the disinfectant exposure requirements for medical devices, Zettel noted that “plastics with significant chemical and photo (UV) resistance will ultimately be the front runners. Some of the PVC alloys and co-polyesters appear to perform well. From a disinfectant manufacturer’s perspective, plastics that retain impact strength as a function of repeated disinfectant exposure are the ones that should be considered in terms of design life.”

Michael Zettel, PDI.

On the topic of brand owners working with material suppliers to choose the right plastics, Zettel noted, “I am aware of some anecdotes where OEMS seek chemical resistance/performance data for enclosure materials, which, in turn, guide their material selection. Unfortunately, this is too often ex post facto enclosure failure. The industry needs to get better at material selection for enclosures prior to launch. Arguably, possible enclosure failures due to poor chemical resistance should be addressed via ISO 14971/FMEA.” That said, he added, “It’s my understanding that some of the major ABS manufacturers are tinkering with their formulas/alloys to improve chemical resistance and mechanical property retention.”

Looking ahead, Denning concluded, “The medical device market is growing at remarkable rates. As the population ages and the global population gains more access to improved healthcare, demand will continue to grow. Devices get smaller, data and technology continue to improve for more personalized healthcare, at-home care becomes an option, and people will be able to be served in parts of the world that weren’t imaginable before thanks to cell phones.”

Lucas Allen, Medical Applications Engineer at Sekisui Kydex, is also scheduled to participate in the panel discussion at Plastec West. Part of the SPE-sponsored MiniTec conference track at the trade show, the session is scheduled for April 12 at 9 a.m.

Part of the Informa Markets – Engineering (IME) West event at the Anaheim Convention Center in Anaheim, CA, on April 12 to 14, Plastec West is co-located with Medical Design & Manufacturing (MD&M), WestPack, automation show ATX, and Design & Manufacturing (D&M). A full conference schedule is available on the event website.

About the Author

Geoff Giordano

Geoff Giordano is a tech journalist with more than 30 years’ experience in all facets of publishing. He has reported extensively on the gamut of plastics manufacturing technologies and issues, including 3D printing materials and methods; injection, blow, micro and rotomolding; additives, colorants and nanomodifiers; blown and cast films; packaging; thermoforming; tooling; ancillary equipment; and the circular economy. Contact him at [email protected].

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