Medical industry manufacturers use polyurethane to create prosthetic liners and, in some cases, even relatively simple prosthetics themselves. But polyurethane also plays an important behind-the-scenes role in the creation of some of the most sophisticated prosthetic devices out there, such as knee and hip replacements like the finished prosthetic pictured above.
Urethane Liners and Protective Masks for Prosthetic Joint Finishing
Two crucial steps when finishing prosthetic joints are polishing the metal parts that need to be smooth, so they can move freely, and then roughening up other areas of the joints so that they can attach to a patients’ bone marrow and other tissues.This finished knee replacement would not have the polished finish that is required to function at such a repeatable rate without a polyurethane mold during the production process.
To polish the designated areas of prosthetic parts, manufacturers place them in tumblers with small-gauge coarse material like one would any other type of metal component. These tumblers typically require a liner that protects the machinery from the abrasive substance that does the polishing. Polyurethane is an excellent material for tumbler liners, thanks to its wear-resistant qualities and the fact that it can be custom molded to conform to nearly any shape or size.
At the very end of the prosthetic joint manufacturing process, implants are sandblasted with grit to create rough patches that help them connect with human tissues. It’s important that the joints are masked at this stage so that only the areas that need to be roughened up are exposed to the sandblaster. The best practice is to use a highly contoured mold that keeps the areas that will be sandblasted visible while covering any other areas. Again, polyurethane’s abrasion resistance and its capacity for custom molding makes it a great option for creating the masks that are crucial to this stage of the prosthetic joint finishing process.
How to Produce Polyurethane Liners and Masks
Hip and knee joints are very particular; they have to be exact in order to work. Properly isolating the areas on them that require roughening requires a lot of care. A mask designed to serve this function needs to be well-fitted so that valuable components aren’t destroyed or adversely affected by sandblasting.
With polyurethane masks, there are two main ways to ensure a snug, exact fit for these protective enclosures. Parts can be shipped to the urethane manufacturer, which then creates a mold based on a cast of the actual part. Or, if the polyurethane provider is set up to receive AutoCAD, Solid Works, Master Cam, or other digital engineering files, it can work off of computer-generated prototypes to create polyurethane molding for the part.
Polyurethane liners for tumblers are a little easier. They can typically be cut from polyurethane sheeting, which any urethane manufacturer should have in stock. It’s just a matter of deciding on a proper substrate with adequate hardness and give and then cutting the material to the proper dimensions.
More than Just Prosthetic Knee and Hip Joints
Polyurethane’s behind-the-scenes involvement isn’t just limited to the manufacture of hip and knee joints. Dental and spine implants require some of the same finishing techniques and can also benefit from urethane’s contributions to the prosthetics manufacturing process.
Bailey-Parks Urethane works regularly with medical clients and has the custom molding experience to meet any prosthetic implant manufacturing needs. For more information about our experience in this field, please give us a call at 1-800-966-2410. We’re happy to answer any questions and to help you address your prosthetic part finishing challenges.