This system was designed to allow controlled movement for cylindrical test subjects. Movement in such a way that it’s roll would pass through a Machine vision system could later read it and process it for errors. 

At the base level, a solenoid was too aggressive and damping the system electronically or using mechanical dampers did not prove efficient. Additional circuit components for electronic damping had to be introduced, while in mechanical damping the solenoid was denser than the platform and proved difficult to damp at that density ratio.

Since the system was already utilising pneumatics for rejected specimen ejection, the superior option for linear action with sufficient damping and speed was pneumatics. Manipulating flow control valves was a simple go-to solution that turned out to be consistent and reliable.

An innovation that I’m particularly proud of is the use of surgical syringes as the specimen stoppers. We could procure them for as low as $0.14 instead of machining 0.25mm stainless steel stoppers from scratch.