超声外场对微模具型腔填充性能的影响

Effects of Ultrasonic Field on Filling Performance of the Micro-Mold Cavity

针对微模具型腔填充困难问题,以细胞培养皿微型制件为对象,设计制造了具有抽真空排气和超声振动功能的微注塑模具。采用单因素短射成型实验方法,研究了高密度聚乙烯(HDPE)和聚丙烯(PP)材料,在不加和施加超声振动时,熔体温度与模具温度、注射压力及注射速度变化对微模具型腔填充率的影响规律。结果显示,不同工艺参数条件下,施加超声振动比不加超声振动时2种材料的微型腔填充率均明显提高;当改变熔体温度时,施加超声振动比不加超声使HDPE材料的微型腔填充率平均提高了10.14%,PP材料平均提高了6.28%。而工艺参数一定时,增大超声功率也使微型腔填充率增加;超声功率增加到300W时,HDPE材料的微型腔填充率提高了10.12%,PP材料提高了4.98%。这表明施加超声外场作用能够促进聚合物熔体流动,提高微模具型腔填充率。

For the difficulty of filling the micro-mold cavity,micro-injection mold with vacuum exhaust and ultrasonic vibration function was designed and manufactured with cell container as its object. The impacting laws of melt and mold temperature,injection pressure and speed changes on the filling rate of the micro-mold cavity were investigated with highdensity polyethylene( HDPE) and polypropylene( PP) by the single factor short-shot molding experiments in the case of with and without ultrasonic vibration. The results indicate that the filling rate of the micro-mold cavity of the two materials with ultrasonic vibration can be significantly higher than that without ultrasonic vibration at different process parameters. The filling rate of HDPE applying ultrasonic vibration is 10. 14% higher than that without ultrasonic vibration for changing melts temperature,which is 6. 28% for PP. But to the certain process parameters,increasing the ultrasonic power can also increase the filling rate of the micro-mold cavity. When the ultrasonic power turns 300 W,the filling rate of the micro-mold cavity of HDPE and PP increase by 10. 12% and 4. 98% respectively. It is suggested that applying ultrasonic field promotes the polymer melt flow and improves the filling rate of micro-cavity.