ASTM F2606 Three-Point Bending Balloon Expandable Vascular Stents and Stent Systems

ASTM F2606-08(2014) "Standard Guide for Three-Point Bending of Balloon Expandable Vascular Stents and Stent Systems" provides guidelines for quantitatively characterizing these products. It provides data that can be used to compare the flexibility of different products by direct comparison of load-deflection curves and by comparison of calculated slopes of the curves.

We recommend Bluehill® Universal software with the TestProfiler module to load and unload the specimen, and to obtain a typical hysteresis curve. The software can provide for the load-deflection data on both segments of the curve, as well as a variety of additional calculations, such as slope, that will allow for direct comparison of a variety of different specimens.

The challenges of testing to this standard:

• Fixture compliance with the standard
• In vitro testing

Our solutions:

• Fixture compliance with the standard – The standard calls for a specific three-point bend fixture. The upper load applicator and the lower static supports must have a radius of 6.35 mm. It is recommended that they are designed to minimize friction by using low-friction materials (like Delrin) or by allowing support rotation through bearings. The fixture shown above is our standard miniature three-point bend fixture, which is not manufactured using any special materials or bearings for friction reduction. However, these materials can be modified and changed to a customer's specific needs.
• In vitro testing – If testing in a bath is required, which would be the case if the specimens are sensitive to temperature change from ambient to 37° C or to hydration, then the fixture can be supplied in stainless steel to prevent rust. The fixture can be easily adapted to our standard BioPuls™ Bath, which can maintain physiological conditions of 37° C +/- 1° C.

It is important to review ASTM F2606-08(2014) in order to fully understand the test setup, procedure, and results requirements.