一种计算挤出吹塑型坯截面平均温度分布的方法

型坯成型中高温的型坯在离开口模后与空气接触冷却 ,导致型坯在轴向方向和径向方向存在温度梯度。由于型坯温度分布直接影响型坯吹胀行为和制品冷却 ,从而影响制品最终的壁厚分布和制品质量。本文在忽略型坯挤出后由于膨胀和垂伸而引起的型坯尺寸和形状的变化 ,利用热量平衡原理对挤出吹塑中型坯挤出阶段型坯截面平均温度分布进行了研究 ,提出了型坯截面平均温度分布的计算公式 ,其计算结果用实验进行验证。结果表明型坯截面平均温度分布与距离机头的长度z呈指数关系变化。此方法为研究型坯吹胀行为及制品最终壁厚分布奠定基础。

A calculation method for average temperature distribution of extrusion blow molding parison sections

High temperature parison out of the die begins to cool after contacting air during parison formation, which results in parison temperature gradients in axial and radical direction. The effect of parison temperature gradients on behavior of parison inflation and part cooling further influence distributions of final part wall thickness and part quality. On the basis of neglecting the change of parison dimensions and shape due to swell and sag during parison formation, average temperature distribution of parison sections on the stage of parison formation by using thermal equilibrium theory is studied and the equation to calculate it is proposed. The calculation results are validated by experimental data. The results show that average temperature distribution of parison sections changes exponentially with distance from the die. The method provides a basis to investigate parison inflation and final parts wall thickness distributions.