Development of an in-process, gap-caused flash monitoring system in injection molding processes

This paper describes the development of an in-process, gap-caused flash monitoring (IGFM) system for injection-molding machines. An accelerometer sensor was integrated in the proposed IGFM system to detect the difference of the vibration signals between flash and non-flash products in the last period of the injection molding filling stage. Through an approach suggested by the statistical process control mechanism, the threshold in the decision-making mechanism of this system was established. That threshold then was used by the IGFM system to determine if flash occurred in the molded products when the machine was running. An experiment was designed and performed by manipulating the variables of gap and no-gap. The experimental testing results indicated that this system could successfully monitor injection-molded products' flash status with approximately 94.7% accuracy while the machine was in process .