Comparing the Ultrasonic Probes with Pressure Sensors in an On-Line Monitoring Approachof Plastic Injection Molding Process

Plastic injection molding process is a multifacetedprocess with many parameters affecting thecharacteristics of the final part. It is difficult to produce apart with desired properties because the interaction of theprocessing parameters; therefore, a multifaceted strategyshould be performed for controlling and monitoring theprocess. In this research, on-line monitoring of plasticinjection molding process of a cubic part has beenperformed using both the ultrasonic non-destructive testby Pulse Echo Method and the traditional pressuresensors. The received signal amplitudes versus theinjection time in the ultrasonic tests have been saved as adiagram for each point on the outer interface between themelt plastic and the mold wall. Using the acquireddiagrams, detachment process and the time of emergingair gaps which are formatted due to polymer shrinkage,have been online monitored. This information arerequired to investigate solidifying phase and also thecooling phase which have being gathered superior withusing the conventional pressure sensors. Flow frontarrival has been online monitored and the time of arrivalof the melt polymer at each point has been determined.The data that was gathered from the ultrasonic test wascompared with the pressure sensors. As a result,although, an ultrasonic probe does not give all thenecessary information for on-line monitoring, the resultsare far better and more efficient than the pressuresensors.

کلیدواژه ها:

ultrasonic non-destructive testing ، plasticinjection molding ، on-line monitoring and pressuresensors