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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 . [ABSTRACT FROM AUTHOR]

As one of the incremental bulk metal forming, the main plastic metal flow of axial closed die rolling (ACDR) process consists of the axial compression and circumferential torsion. The key difference between the ACDR and forging processes should be concentrating on the plastic deformation zone (PDZ) evolution, especially on the condition of thermal deformation. Therefore, the verified FEM and corresponding experiment have been proposed to find out the systematic rule of PDZ. The thermal parameter distribution of the workpiece has been explored to obtain the PDZ evolution at different deformation extent. PDZ evolution mode has also been proposed, and the distribution of microstructure/hardness is given to the evidence of PDZ mode. The results show that the PDZ spreads from the contact area of the upper surface of the lower/side surface in ACDR process. Multiple thermal parameter evolution in ACDR process could be found through the analysis of microstructure morphology. Also, microstructure orientation could be the fundament of PDZ evolution. The cooling rate and the periodic evaluation of thermal parameters should be the main factors for the microstructure evolution, including the distribution of lamellar a and globular a. Then, the extent and range of PDZ could be defined through the observation and analysis of hardness evolution. [ABSTRACT FROM AUTHOR]