The auto-injector is becoming an ever more popular choice for patients and doctor wishing to replace the traditional injection method. However, the manufacturers themselves require lengthy iterations in the design process to determine the spring which produces an ideal injection time. Instron’s solution to this challenge bypasses the need to test multiple springs by utilizing the ElectroPuls’s advanced control capabilities to produce a unique spring simulator.

Instron solves the challenge of multiple spring testing using Modal Control, an advanced feature of the 8800 controller that creates a composite channel to allow the applied load to vary with actuator position, as is representative of an actual spring. The user simply needs to specify the initial preload and spring stiffness in order for the system to adjust itself based on the actual load seen by the syringe, and can then determine if the chosen parameters for spring stiffness and preload have yielded an ideal auto-injector dispensing time for a given drug. This unique combination of features within WaveMatrixTM software allows manufacturers to quickly establish which spring would be suitable for a given auto-injector, without the need for tedious physical testing of the springs themselves.

For more information on spring simulation, please click on the link under "Related Literature" below.