Syringe needle fracture resistance under bending loads

Requirement

Dong-A ST, based in South Korea, is becoming well established as a global company in the field of ethical pharmaceutical drugs.

It also has a medical device business and multi-faceted Research and Development division.

The company wanted to test the suitability and strength of syringe needles, with the primary purpose of ensuring that the needle itself would remain intact even in the event of repeated and extreme bending.

Solution

Mecmesin Korea worked with the team at Dong-A ST to design and build a special jig to securely hold the range of syringe assembly sizes and apply a precise bending condition to the needle.

The required test procedure indicated an initial bend to an angle of 12 degrees, from which the needle was re-straightened, followed by another bend in the same plane to a full 90 degree right angle.

The sample must remain unbroken and in one piece for the complete test cycle to pass the check.

A single column MultiTest 2.5-i test stand was supplied to enable the test method to be uniquely programmed for this requirement.

Emperor Force software allows the research team to control the speed and displacement of the probe as it creates the flexure in the sample and the force characteristics of the full deformation can be measured to provide a complete picture of the behaviour.

The ability to write a library of routines will also enable other tests to be performed on similar components (see Mecmesin’s Examination of Needle and Syringe Force Testing white paper).

ISO 9626 - Stainless steel needle tubing for the manufacture of medical devices, provides a basis for similar needle material strength testing, but this custom solution allows Dong-A ST to establish their own internal quality standards to continue their growth and further enhance their reputation.

Test equipment

• MultiTest-i 2.5 software-controlled force tester
• 1 kN ILC intelligent loadcell
• Custom fixtures: knife edge probe, lower fulcrum and syringe housing clamp