FORT WAYNE, IN. – As implantable medical devices keep getting smaller, it is becoming more and more challenging to produce wire that combines decreasing diameters with the fatigue strength required for critical implant applications. This is why Fort Wayne Metals has developed the patent-pending NDR® process for which it has now gained trademark registration.
NDR® stands for “Nanograin Damage Resistant” and denotes a thermal-mechanical process designed to produce nanoscale microstructural refinement. This refinement is evidenced by a significant increase in the material's ability to resist damage during high cycle mechanical loading, for example as encountered during the service of a long-term cardioverter defibrillator lead implant due to chronic pulsatile stresses. “While our results may not translate into every application, we have observed improvements in the rotary beam fatigue strength of up to 83% in 0.007” diameter ASTM F562 wire during our testing,” states Jeremy Schaffer, Senior Research & Development Engineer. “By leveraging microstructural mechanisms through significant refinement of the grain size in NDR® wire, we can increase fatigue strength without changing the chemical makeup of the alloy. And we can do it without significant impact to other wire properties like corrosion resistance.”
Fort Wayne Metals can apply the NDR process to non-precipitation hardening, non-sensitizing, implant-grade alloys such as those called out by ASTM F562 (35N LT® wire or MP35N® wire), ASTM F1058 (FWM 1058® wire) and ASTM F138 (316LVM).
Fort Wayne Metals Research Products Corporation is a leading manufacturer of high-quality precision wire, strands and cables, and component assemblies for medical devices and other demanding applications.