Condition monitoring of dynamic system for packaging industry

This work arises from the requirement to monitor the packages separation downstream of the packaging machine: the asepticity of the content could be compromised by a non-compliant splitting system. The main effects that influence the system functionality are the impact and the dynamic stress. To emulate the real process, a test rig was designed with multiple stations to collect a larger amount of data. Each of these was sensorized with strain gauge load cells to monitor the dynamic and the impact phenomena that occur. Also the oil temperature and the pressures in the hydraulic implant were kept under control. The force curves have allowed to analyse different events/effects: the stiffness of the system, the force required for the separation of the material, the progressive obstruction on the rear side of the stations due to material scraps. The acquired parameters of the hydraulic system have shown an interesting response in terms of rapidity of the mechanical system: the more the temperature increases during the day, the lower the force delay in reference to the control signal. This information has permitted to establish the optimal working condition, maintaining the operating oil temperature around 40 °C. All the logged data have contributed to assess the state of the system, advising when a maintenance operation has to be performed. Some warning events that could be detected are the accumulated material scraps that enhance the impact effects, an anomalous stiffness of the components or a damaged tool that causes higher force peaks. The condition monitoring obtained allows to schedule only required service operations, ensuring the quality of the packaging separation interface and reducing the maintenance costs.