Determination of the Breakaway and Turning Torque on Screw Caps


Push and Turn Tests on Screw Caps

This test determines the superimposed compression/torsional forces on opening and closing of childproof containers or pharmaceutical packaging. For this, a zwickiLine tabletop testing machine of Fmax 2.5 kN and an additional torsion drive of 5 Nm torque are used. The two test axes can be used for independent or combined axial/torsion tests as required, the package being opened via a rotary movement with superimposed axial loading. Important parameters are the required opening torque and the functioning of the childproof mechanism.

Test Fixture for Tip Cap Breakaway Torque with a Single-Axis Testing Machine

Torque is applied to tip caps on disposable medical syringes to determine their breakaway torque. The syringe barrel is gripped firmly in a holding fixture. The tip cap is held in a positive-fitting fixture with toothed pulley and belt. The end of the tip cap is carried in a support bearing. To prevent transverse frictional forces, the holding fixture and support bearing are mounted on a common precision slide carriage. During the test the positive-fitting tip cap holder is turned 180° by testing machine travel. This ensures that the tip cap is fully twisted off.

Torsion Tests on Eye Drop Bottles

This test fixture is rotated via a gearbox ratio by driving the crosshead. The integrated torsion transducer records the torque throughout the entire rotation. 
Eye drops2
Eye drops1