Testing bone-screws – Zwick presents compact testing system

The use in accident surgery of innovative implants made of various materials is becoming increasingly frequent, with a similar trend apparent in the development of fixing technologies.

From Zwick comes a compact zwicki-Line system for testing the mechanical properties of new developments in bone screws.

In common with many areas of medical technology, the product development of bone screws sees the constant application of new materials and designs. These new developments must be tested in accordance with ASTM F543-07 Test A4 ‘Test Method for Determining the Self-Tapping Performance of Self-Tapping Medical Bone Screws’. The test sequence required by the standard imposes severe demands on the testing system; for example a continuous rotational speed of 30 r.p.m. must be maintained while the axial force during the tightening procedure is increased at a rate of 2 N/s. Zwick’s  compact solution for this test comprises a zwicki-Line testing machine (Fmax 5 kN) combined with an additional torsion drive (Mmax 20 Nm).

Versatile test fixtures are used to position the bone substitute material in the testing machine. The advantage of the zwicki-Line with torsion drive is that  the machine can be used both for pure axial or torsional tests and for tests involving superimposed forces, for example on screws, childproof pharmaceutical packaging, luer-lock connectors and insulin pens.

The machine is designed to allow upgrading with external sensors or environmental simulation systems (e.g. temperature chambers or water baths) whenever required, while standardized connection technology naturally enables Zwick’s wide range of specimen grips to be used on this machine.

The testXpert® II testing software is optionally available equipped with Expanded Traceability in accordance with FDA 21 CFR Part 11, enabling documentation of the entire test environment. This guarantees full, manipulation-free documentation of all actions performed in testXpert®, provides electronic signatures and satisfies the strict requirements of the USA’s food and health authorities.