一段式射拉吹製程多穴充填流動平衡研究

Study on Filling Multi-Cavity Flow Balance of One-Step Injection Stretch Blow Process

本文研究一步法射拉吹塑成型工藝(ISBM)，其為一種高溫脫模方法，瓶胚溫度分佈會影響後續吹瓶的厚薄分佈。透過Hagen-Poiseuille流動理論和單純形法Nelder-Mead優化方法，依據所需的質量流率去計算熱澆道的壓力和剪切應變率。另外，以最小化多腔流道之間的壓力差和剪切應變率差，可以改善多模穴的射出充填的瓶胚溫度差異。藉以提供更穩定的ISBM工藝，並提升射拉吹工藝的瓶子質量。本文以五腔熱流道平衡為例，說明如何降低多模穴的瓶胚的溫差。儘管一般研究熱澆道的充模平衡分析，可使用各種模流分析軟件進行。然而，但流道的幾何形狀需要事先準備3D CAD建模非常耗時。所以透過單純形法將可自動計算得到模流分析的完整尺寸，有助於大幅減少開發時間。本研究結果顯示，使用PET塑料作為指數流體計算流道幾何形狀的最小壓差平衡和剪切應變率優化，初步驗證其可以有效改善多模穴的瓶胚溫度差異。

This paper investigates the one-step injection stretch blow molding (ISBM) process, which is a high-temperature demolding method that affects the thickness distribution of the blown bottles due to the temperature distribution of the preforms. Using the Hagen-Poiseuille flow theory and the Nelder-Mead optimization method, the pressure and shear strain rate of the hot runner is calculated based on the required mass flow rate. Additionally, minimizing the pressure and shear strain rate differences between multiple cavity channels can improve the temperature difference of the preforms injected and filled in multiple cavities, providing a more stable ISBM process and enhancing the quality of the blown bottles in the ISBM process. This paper uses a five-cavity hot runner balance as an example.
Although various mold flow analysis software can be used for the balance analysis of the hot runner filling process, the preparation of the runner’s geometry in 3D CAD modeling can be time-consuming. Therefore, using the simplex method to automatically calculate the full dimensions of the mold flow analysis can significantly reduce development time. The research results show that using PET plastic as the index fluid to calculate the minimum pressure difference balance and shear strain rate optimization of the runner geometry can effectively improve the temperature difference of the preforms in multiple cavities.