WIRE & CABLE TECHNOLOGY JANUARY 2017
Testing Small Diameter Nitinol Wire Jean R. Gould, Marketing Manager, Magnetic Analysis Corp., Elmsford, NY, USA, says, “Magnetic Analysis Corp. has introduced an eddy current test for detecting cracks and inclusions in Nitinol wire. An alloy made of approximately equal parts nickel and titanium, Nitinol is referred to as a SMA (shape memory alloy). It is often used in critical surgical applications such as stents and heart valves, where its ability to be deformed at one temperature, for example during insertion into the body, and then recover its original, undeformed shape when it is heated above its ‘transformation temperature’ after exposure to typical body temperatures of 98.6°F (37°C), is essential.
MAC's small diameter 0.019" ID eddy current coil can be used for detecting cracks and inclusions in Nitinol wire. Wire passes through the center hole at right.
MAC’s small diameter eddy current coil. Connector is shown at top, wire passes through the center hole for detecting cracks and inclusions in Nitinol wire.
Nitinol wire is often subject to cracks and inclusions, which can form from the melting process during production, and these need to be detected. Using a Multimac® eddy current instrument with its phase sector output gate and MAC’s Wiretester test coils for small diameter applications, cracks and inclusions can be detected and separate counts for both conditions can be provided, while rejecting only the wire with cracks. MAC can supply test coils as small as 0.013" ID.” www.macndt.com Special Tester for Wire & Stranded Wire Information from Zwick Roell, Atlanta, GA, USA, says, “Stranded wire consists of individual wires wound together.
