Determination of the Breakaway and Turning Torque on Screw Caps

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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.
Pushturn2
Pushturn3
Tipcap

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. 
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Eye drops1
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