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Plastic’s Edge over Metal in Medical Device Fabrication

TPEs allow designers to improve the overall functionality of medical devices, while the flexibility of PEEK-based orthopedic implants is a better match for bone than stainless steel.

February 21, 2022

3 Min Read
molded PEEK part for medical application
Image courtesy of Performance Plastics

Rich Reed

As technology continues to advance, medical device designers are being asked to increase performance and longevity of devices while decreasing costs. One of the most effective methods of achieving both goals is through a metal-to-plastic conversion using a medically compatible resin.

Newer polymers allow for the design of multiple features into one molded component and can replace metal components or multiple smaller parts. By improving the product design and manufacturing process with the latest materials and plastic manufacturing techniques, medical device designers can improve performance of the medical device while reducing its cost.

Medical devices continue to get smaller and more complicated. The size and complexity issues present opportunities for metal-to-plastic conversion. Small tools often are used by professionals who are gloved, and resins offer the ability to apply texture and reduce weight. By using a material that provides improved wet-grip characteristics and ergonomics, designers are able to improve the overall functionality of products. The use of properly selected thermoplastic elastomers (TPEs) allows for products that withstand sterilization to be made more effectively.

Instruments that must be repeatedly cleaned and sterilized, sometimes multiple times a day such as dental instruments, can now be made from high-performance materials such as polyether imide (PEI), or polyetheretherketone (PEEK) polymers. These improvements result in better medical devices often at lower manufacturing costs.

Another advantage of medical resins is their biocompatibility. There are polymers currently available that can be used as joint-replacement materials. These materials have been found to provide better long-term outcomes for patients than the antiquated stainless-steel materials of construction.

Medical resins are ideal for bone implants. Devices made from PEEK polymer are a better match to the normal flexibility of a bone for implants. When a stainless-steel implant is used, the adhesion between the implant and bone tends to loosen over time, because the bone has a small amount of flexibility. A stainless-steel implant does not flex.

By using PEEK polymer as the implant stem, rather than traditional stainless steel, the polymer has close to the same flexibility as the bone and there is a reduced tendency for the implant to loosen over time. This compatibility between bone and polymer makes a more effective medical device — one that will allow better long-term outcomes, especially as the average life span of an implant increases in tandem with the life expectancy of the general population.

About the author

Rich Reed is Vice President of Sales and Marketing at Performance Plastics. He can be reached by phone, 513/321-8404, or via e-mail, [email protected].

Performance Plastics specializes in injection molding of high-performance plastics. PEI, PEEK, FEP, and PFA are premium medical-grade resins that are ideal for the manufacturing of medical parts and components. Medical-grade resins provide excellent mechanical properties and are highly resistant to chemicals and thermal degradation, making them highly desirable materials for plastic injection molded products within the medical industry. For more information, go to the Performance Plastics website.

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