The advantage of plastic over metal in medical device manufacturing

As technology continues to advance, medical device designers are challenged to increase device performance and longevity while reducing costs. One of the most effective methods to accomplish both of these goals is to perform a metal-to-plastic conversion using a medically compatible resin.

The new polymers allow the design of multiple features in a single 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 the performance of the medical device while reducing its cost.

Medical devices continue to get smaller and more complicated. Size and complexity issues present opportunities for metal-to-plastic conversion. Small tools are often used by professionals who wear gloves, and resins provide 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. Using properly selected thermoplastic elastomers (TPEs) makes it possible to more efficiently manufacture products that are resistant to sterilization.

Instruments that need to be cleaned and sterilized repeatedly, sometimes several 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 currently polymers available that can be used as joint replacement materials. These materials have been shown to provide better long-term patient outcomes than outdated stainless steel construction materials.

Medical resins are ideal for bone implants. PEEK polymer devices better match the normal flexibility of bone for implants. When a stainless steel implant is used, the bond between the implant and the bone tends to loosen over time, as the bone has low flexibility. A stainless steel implant does not flex.

By using PEEK polymer as the implant stem, rather than traditional stainless steel, the polymer has almost the same flexibility as bone and there is a reduced tendency for the implant to loosen over time. This compatibility between the bone and the polymer makes it a more effective medical device, which will allow better long-term results, especially as the average lifespan of an implant increases in parallel 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 by email, [email protected].

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

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