Machine Vision Solutions

Rubber plunger inspection machine


The pharmaceutical rubber plunger is the moveable component within the barrel that is especially designed to create a secure airtight flexible closure inside the syringe. When a syringe is filled or prefilled with medication this rubber plunger is the closing part on the handle side.

The above picture clearly shows that a rubber plunger is always in contact with the medication itself.  This contact must be absolutely guaranteed without any influence from the rubber plunger itself.  This makes that a plunger is a vital element to be controlled in the syringe medication method.

5th generation inspection machines

Already 20 years ago, Simac designed and built its first rubber plunger inspection machine. Now, the 5th generation machines belong to the world fastest inspection systems for Pharmaceutical rubber plunger inspections. It is a complete quality control system within clean-room conditions ISO class-5.

Modular designed inspection system

The designed system is flexible and can be easily adapted to specific customer needs.
Below you see an inside view.


Not visible in the inside view are the two communication terminals on the outside of the machine.

  • One screen for the HMI: Human Machine Interface to control the machine operation.
  • One screen for the inspection results that controls all the vision results and statistics.

A. The bowl feeder is automatically fed from the supply bunker. In the bowl feeder the plungers are correctly positioned and lined-up. Form the line-up the plungers then go one by one into the separation wheel. 

B. From the Bowl-feeder line-up the plunger is taken into the separation wheel.

C. From the separation wheel the plungers are handed over into the first inspection wheel. Here the plunger gets an inside inspection on the forming of the ‘ inside thread’. The ‘inside thread’ connects the plunger to the syringe handle.  Only oke plungers are continued to the next mirror disc for further inspection.

D. On the mirror disc the outer surface of the plunger is inspected. The mirror disc is used to get maximum light on the plunger surface to make a crisp and clear inspection possible.

E. In location ‘E’ there are 5 to 6 camera’s to inspect the total outside surface of the stopper.

F. At ‘F’ the plunger goes through a metal detector and is then finally selected for ejection or rejection. The ejection system separates good from bad, counts the numbers per bag, separates sample for testing and is the last check in the product-flow-control system.