Testing of Injection Needles

An injection needle consists of a tube of varied length, inner diameter, and outer diameter. It is beveled and tapered on one side and can be held in a variety of ways on the other side. Injection needles are used to inject or withdraw fluids from the body.
Cannula test fixture

Penetration Force and Track Force to LAB 530 and ISO 11040-4

A mounting fixture with a standard foil is used to determine the penetration force and track force of cannulae and injection needles up to 200 N to LAB 530 and ISO 11040-4 (F) . This foil is penetrated by a needle, and the force sequence is recorded during the various phases of injection.

The foil can be gripped at a 90° angle to the needle, as defined in the standard. In application-driven injection tests, a clamping fixture with adjustable injection angle can also be used. Needle holders facilitate the testing of needles with a Luer connector or bare cannula shaft, as well as syringes with needles or prefilled syringes.

Needle Withdrawal Force

Injection needles are glued in prefilled syringes or needle holders. To test the needle withdrawal force, both the needle and the syringe and/or holder must be gripped. A male Luer lock adapter can be used for injection needles that are inserted into syringes. When testing prefilled syringes to ISO 11040-4 (Annex G1), the prefilled syringe is held at the flange. Typically, the tensile test is performed only up to a defined force. For development purposes, a complete needle withdrawal test is also performed. Slight jaw breaks at the needle or the failure of the syringe flange before the maximum force is reached could occur.
Needle withdrawal force ISO 11040-4
Needle withdrawal force SG side
Needle withdrawal force turret frontal

Flexure Tests to DIN EN ISO 9626

The break resistance of injection needles is determined to DIN EN ISO 9626 (Annex D) using a 2-point flexure test. The needle is held on one side and the free side is bent at a defined angle.

To test the stiffness of the cannula tube to DIN EN ISO 9626 (Annex C), a 3-point flexure test kit is used. A defined flexure separation that corresponds to the needle gage must be selected.