Development of an innovative control system to ensure caps compliance in pharmaceutical packaging lines

This thesis presents the development of an innovative cap control unit for a Sterifill pharmaceutical packaging machine, designed to inspect caps upstream of the capping station and reject non-compliant ones before they are applied to the vial. The project was developed during an internship at IMA S.p.A., within the IMA Life division, and addresses the industrial need to reduce the economic losses caused by the rejection of already filled products due to defects affecting a low-cost component such as the cap. The proposed unit operates in parallel with the main machine and consists of a rotating starwheel, which transports the caps through the inspection stations, and a deviator, which rejects defective caps. Cap inspection is performed by means of a camera and a computer vision algorithm, while the control logic is implemented on the PLC. Since the unit must work asynchronously with respect to the main machine and must guarantee the continuous availability of compliant caps, an independent Virtual Master was adopted for motion control. In parallel, a custom lightweight Quality architecture was developed to track the caps along the unit, evaluate camera results, and manage rejects and abnormal conditions such as camera faults, invalid data, unexpected data-valid transitions, and rephasing operations. The developed software was validated on a simplified test bench equipped with the two electric axes of the unit. Although the final integrated machine was not available, the tests made it possible to verify the correct behaviour of the motion control, the quality handling, the reject logic, and the HMI diagnostics. The results demonstrate the feasibility and industrial relevance of the proposed solution, which improves product saving, process robustness, and modularity of the machine software architecture.