Bone Screw Testing to ASTM F 543 07

Determining torsional properties of metallic bone screws

Biomedical tests require precision and accuracy, the variety of tests needed call for versatility within the fixtures and the software. The test requires the torsional yield strength, maximum torque and breaking angle to be determined. Single testing machines have previously struggled to fully comply with ASTM F 543-07 due to the many test configurations. 

Using multiple stage tests

The test was carried out using a Linear-Torsion ElectroPuls with multi-turn mode mounted with a bone screw fixture. Independent control of the linear and torsional axis means that the linear axis can be run in load control, while the torsional axis is run in rotary control. WaveMatrix allows a number of steps to be implemented in order to automatically balance the load string and detects when the specimens properties have changed.

Analysing the results

When conducting the test, failure at 8.40Nm and 8.79Nm was observed with both specimens respectively, this can be seen on the graph on the left. The E10000 or E3000 Linear-Torsion machine with supplied fixtures allows you to fully comply with the ASTM F 543-07 standard.