微注射浇注系统对微制件熔接缝形成的影响的模拟研究

Simulation of Micropart's Weld Lines by Injection Molding

微塑件的需求逐年增加,微注射是批量生产高精度微塑件的主要手段,但与宏观注射方法相比,制件尺寸的微小化也给微注射在理论、工艺、设备、检测等方面带来了难题。浇注系统、熔接缝的位置和数目是影响微制件质量的主要因素,本工作就此进行了数值模拟,得出了微成型与传统注射成型工艺参数的差异。结果表明:微注射成型的温度、压力和速度均高于传统注射成型,微注射成型过程中温度是保证微注射能否顺利进行的关键,微注射成型的模具温度必须高于聚合物材料的玻璃化转变温度,因此对微注射成型必须进行有效温控。

With the inc focus as it is the main reasing demands of plastic microparts, microinjection process is becoming the method for producing the microparts with high precision in batch. However, compared with the conventional injection process, the minimization of parts＇ dimensions has brought the problems such as the theory, process, equipment and measurement. As the gating system, the positions and numbers of melding lines are the main concerns influencing the microparts quality. In this paper, the numerical simulation has been carried on to obtain the process parameters difference between the microinjection and conventional injection. The results show that the temperature, pressure and velocity of microinjection are higher than conventional process, and the temperature is the key factor to ensure the success of microinjection. Furthermore, the mould temperature should be high than the vitrification point of polymeric material, and the temperature of microparts needs to be control efficiently.