纵向超声波辅助微注塑方法

微注塑过程中，聚合物熔体在微小腔体中流动时充模阻力比常规注塑大，这影响了熔体填充效果，同时热量损失的不均衡性和不确定性容易导致注塑精度不高．提出了纵向超声波辅助微注塑方法，并对超声波振动对聚合物熔体的作用机理进行了探讨，分析了超声换能器结构对应力、振幅和响应频率的影响．基于对微注塑过程的模拟结果，开发了纵向超声波辅助微注塑装置．通过在微注塑过程中纵向超声波对熔体的能量作用降低熔体黏度，改善了熔体流动和充填性能．为了验证超声波辅助微注塑的效果，进行了菲涅尔透镜实际注塑实验．实验结果表明，相同的注塑工艺条件下，超声辅助微注塑过程中聚合物熔体的充填性能提高了6．91％．

Longitudinal Ultrasound-Assisted Micro-Injection Moulding Method

Polymer melt flowing in micro/nano structures in micro-injection moulding is relatively insuffi- cient in mould filling, compared with that in a conventional injection moulding, since the flow resistance of polymer melt flowing in micro-channel is larger, and product quality is affected by uncertainty and non- uniformity of heat loss. In this paper, a longitudinal ultrasound-assisted micro-injection moulding method was proposed, the mechanism of ultrasonic vibration affecting polymer melt was presented, and the effects of ultrasonic amplitude transformer on stress condition, amplitude and resonance frequency were ana- lyzed. An ultrasound-assisted micro-injection moulding system was developed based on the simulation re- sult of micro-injection moulding process. The system decreased the viscosity of polymer melt and im- proved fluidity and mould filling capability due to the energy exchange between longitudinal ultrasound and polymer melt. In order to verify the effect of ultrasound-assisted micro-injection moulding, an ultra- sound-assisted micro-injection moulding experiment on Fresnel lens was conducted. Experimental results show that the mould filling capability of polymer melt in micro-injection moulding proeess is improved by 6.91% with the same injection parameters.