ISO 594 Testing of Conical Luer Fittings
Conical Luer fittings are commonly used in medical devices, such as syringes, hypodermic needles, and catheters, to achieve a leak-free connections between medical devices.
Luer fittings can be a Luer slip or a Luer lock. A Luer slip is a tapered cone that connects to a tapered cavity. A Luer lock contains a Luer slip fitting with threads that can be connected.
There are four tests in ISO 594 that are applicable to mechanical testing:
1. Luer Assembly: Ensures that the Luer specimen can be assembled with minimum axial force and torque.
2. Separation Force: Ensures that the Luer specimen remains attached to the reference fitting when an axial load is applied.
3. Unscrewing Torque: Ensures that the specimen Luer remains attached under a specific unscrewing torque in the counterclockwise direction.
4. Resistance to Overriding: Ensures that the threads cannot be overridden by a specific screwing torque in the assembly clockwise direction.
An Electromechanical system with a torsion add-on can be used to perform these tests. The torsion add-on can be added to any 5900 single column testing machine to add rotational capabilities. The system operates on Instron’s Bluehill® 3 Software with TestProfiler. Bluehill 3 is able to performed closed-loop control for axial testing and measures axial displacement, rotary displacement, axial load and torque. A biaxial Dynacell load cell is mounted to the base of the machine. Advanced screw action grips are used to grip the product. A slight axial load can be placed on the bottle cap to push it down before rotation begins.
Simple multi-axis testing is often necessary to test the performance of medical devices, such as bone screws, luer locks, wires, child-proof medicine bottles, and tubing. Like much of the medical device design industry, new products and materials are being used to advance the industry and often require stringent testing per ASTM and ISO standards. Some of these standards, such as ASTM F543 for testing bone screws, requires that the test is performed with both axial and torsion control. The Instron® Torsion Add-On for Electromechanical Universal Testing Systems is designed for simple, simultaneous axial and torsional testing of devices and/or components, but can be used for purely uni-axial or torsional testing. The Torsion Add-On easily mounts to any new Instron 594X or can be retrofitted in the field on existing 594X frames. The torsion drive is mounted above the machine’s crosshead and all required electronics are mounted to the single column, thus maintaining the frame’s small footprint.
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