中国塑料 ›› 2024, Vol. 38 ›› Issue (4): 60-66.DOI: 10.19491/j.issn.1001-9278.2024.04.010

• 加工与应用 • 上一篇    下一篇

注射成型中聚合物熔体信息的超声在线测量

陈豪1, 焦晓龙2, 朱宁迪2, 董正阳1, 张剑锋1, 赵朋1()   

  1. 1.浙江大学机械工程学院,杭州 310030
    2.海天塑机集团有限公司,浙江 宁波 315821
  • 收稿日期:2023-08-29 出版日期:2024-04-26 发布日期:2024-04-22
  • 通讯作者: 赵朋(1983—),男,博士,教授,研究方向为聚合物高性能成型技术及装备,pengzhao@zju.edu.cn
    E-mail:pengzhao@zju.edu.cn
  • 基金资助:
    宁波市科技创新2025重大专项(2021H002);浙江省‘尖兵’‘领雁’研发攻关计划项目(2022C01069)

Ultrasonic on⁃line measurement of polymer melt information in injection molding

CHEN Hao1, JIAO Xiaolong2, ZHU Ningdi2, DONG Zhengyang1, ZHANG Jianfeng1, ZHAO Peng1()   

  1. 1.School of Mechanical Engineering,Zhejiang University,Hangzhou 310030,China
    2.Haitian Plastic Machinery Co,Ltd,Ningbo 315821,China
  • Received:2023-08-29 Online:2024-04-26 Published:2024-04-22
  • Contact: ZHAO Peng E-mail:pengzhao@zju.edu.cn

摘要:

提出了成型中聚合物熔体温度和密度的超声在线测量方法,并与其他方法对比验证了超声在线测量方法的正确性。设计并制造了底部不封口的流变模具,搭建了超声信号与温度、压力信号采集平台,采集超声信号后进行分析计算,得到聚合物熔体内超声速度变化曲线,结合压力、温度信号,对注射成型中熔体信息进行计算分析。结果表明,超声速度信号可无损定性反映熔体在型腔内的演化过程;借助于压力信号可迭代计算熔体温度演变曲线,与红外光纤温度传感器测量结果相比误差小于6 %,实现了对聚合物熔体温度的有损定量分析;对超声信号在时/频域内分别计算分析,得到声阻抗与声速的变化曲线,进而计算得到熔体密度的演变曲线,与压力⁃体积⁃温度(PVT)方法计算得到的结果十分吻合,均方差仅0.040 3 g/cm3,实现了对聚合物熔体密度的无损定量测量。超声测量技术可实现注射成型中聚合物熔体信息的在线测量,在实际生产过程中具有广阔的应用前景。

关键词: 注射成型, 熔体信息, 温度, 密度, 超声测量

Abstract:

During the injection molding process, the polymer melt undergoes intricate changes in temperature and density, directly impacting the final product quality. An ultrasonic on⁃line measurement method for monitoring the temperature and density 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 computational 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 ultrasonic signal, the changes in the acoustic impedance and sound velocity were obtained, enabling the calculation of the evolving 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 measurement 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.

Key words: injection molding, melt information, temperature, density, ultrasonic measurement

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