微注塑充模流动中的粘性耗散效应

Viscous Dissipation Effects in Micro-Injection Molding Filling Flow

微注塑成型中的粘性耗散效应引起的熔体充模流动行为变化,直接影响微塑件的成型质量。应用双料筒毛细管流变仪与微尺度口模和高精度温度传感器等组成的测量装置,对丙烯腈-丁二烯-苯乙烯共聚物(ABS)熔体以不同剪切速率和口模入口温度,流经直径350μm和500μm而长径比不同口模时的粘性耗散效应进行了实验测量和数值模拟。结果表明,微通道中的熔体粘性耗散效应随剪切速率的增加而明显增强,随通道直径的减小和入口熔体温度的升高而减弱;但通道直径一定时,长径比的增大也会导致粘性耗散作用增强。

The change of melt filling flow behaviors caused by viscous dissipation effects in micro-injection molding directly affected the quality of micro-parts. By using the experimental device made by twin-bore capillary rheometer, micro-scale dies and high-precision temperature sensors etc, the viscous dissipation effects of acrylonitrile-butadiene-styrene （ABS） flowing in micro-channels of 350 μm and 500μm diameters with different aspect ratios were studied through the measurements and numerical simulation with various shear rates and die inlet temperatures. The results show that, the viscous dissipation effects in micro-channels increase significantly with the increasing of shear rate, and decrease with the decreasing of die diameter and rising of inlet temperature. But to the certain channel diameter, the increase of aspect ration will strengthen the viscous dissipation effects.