Ultrasonic on-line measurement of polymer melt information in injection molding
During the injection molding process,the polymer melt undergoes intricate changes in temperature and density,di-rectly impacting the final product quality.An ultrasonic on-line measurement method for monitoring the temperature and den-sity of the polymer melt during molding was proposed in this article,and the results validated the accuracy of this method through comparisons with alternative approaches.A non-sealed rheological mold with an open bottom was designed and manufactured.An acquisition platform was established for collecting the ultrasonic signals as well as the temperature and pressure signals.Following with the signal collection,analysis and computations were performed to derive the variation curve of ultrasonic velocity within the polymer melt.Through incorporating the pressure and temperature signals,the com-putational analysis of melt information during injection molding was conducted.The experimental results demonstrated that the ultrasonic velocity signal could qualitatively reflect the melt evolution process within the mold cavity without a damage.Through leveraging the pressure signal,the iterative calculations of melt temperature were performed,showing an error of less than 6%compared to the results from infrared fiber-optic temperature sensors.This resulted in a quantified analysis of polymer melt temperature with a minimal degradation.Through separating the time/frequency domain analyses of the ultra-sonic signal,the changes in the acoustic impedance and sound velocity were obtained,enabling the calculation of the evolv-ing density curve of the melt.This curve closely aligned with the results obtained through the pressure-volume-temperature method,presenting a mere mean squared deviation of 0.040 3 g/cm3.As a result,the non-destructive quantitative measure-ment of polymer melt density was achieved.This ultrasonic measurement technology enables the real-time monitoring of polymer melt information in injection molding,exhibiting vast potential applications in the practical production processes.
国家科技期刊平台
NSTL
万方数据
维普
