Swedish premium fastener specialist BUMAX has been picked as sole supplier of screws for advanced and durable prosthetic knees by German manufacturer of a waterproof and submersible prosthesis knee and foot system, WEIGEL+ medical.

BUMAX SDX 109 high strength super duplex fastener was the only screw on the market capable of providing a prosthetic knee joint with the necessary high strength and corrosion resistance – to contribute to providing prosthesis solutions to people around the world.

The Niagara Foot is an affordable, high-performance prosthetic foot designed for individuals with active lifestyles brought to the market by WEIGEL+ medical (development and manufacturing) and DOI ortho-innovativ (distribution and education). It will be fitted with BUMAX fasteners for maximum strength and corrosion resistance.

The BUMAX SDX 109 will also be used for the All Terrain Knee, a mechanical prosthetic knee joints used by those with above-knee amputations. Both prosthetics can be used in aquatic environments as they purely work mechanically. However, this requires that all components are resistant to saltwater, including the screws.

“The only screw good enough for us”

“We tried a variety of stainless steel screws when developing the waterproof knee joint, but BUMAX SDX 109 was the only screw that provided both the strength and corrosion resistance we required,” explained Jochen Weigel, owner of WEIGEL+ medical and co-owner of DOI ortho-innovativ.

Super duplex stainless steel fasteners are unique as they combine super high strength with excellent corrosion resistance compared with alloy steel fasteners. They have two-phase microstructures containing ferrite and austenite and are cold headed and thread rolled.

“BUMAX SDX 109 is from our high strength Super Duplex fastener range and provides excellent mechanical properties, and exceptional resistance to general crevice, pitting and stress corrosion,” said Klaus Vogt, Business Development Manager at BUMAX. “Due to their high levels of chromium and molybdenum, super duplex grades provide even greater corrosion resistance than duplex grades.”

Author: Lars Holm | Managing Director, BUMAX

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