孔板模具结构对挤出造粒形貌的影响研究

为深入研究挤压造粒过程中孔板模具对造粒药粒形貌和质量的影响,运用有限元方法,采用数值模拟对挤压造粒过程药料的受压情况、孔板压力分布情况进行分析,通过仿真模拟手段对孔板模具的孔数、孔径、孔板厚度进行初步模拟设计,按照孔板模具设计原则进行多方案模具设计,通过代料试验,研究了不同孔数、孔径、孔分布、模具材质等因素对造粒效果、药粒尺寸、造粒得率、药粒烘干、药料塑化成型过程的影响。结果表明:当孔板模具设计为孔径10 mm/162孔、孔排列成正六边形、材质为铜质、孔设计为小进大出的结构时,药粒受压分布均匀,造粒所得药粒塑化适当、尺寸均一,获得挤压造粒最佳药粒形貌和质量,保证后续塑化过程中药粒能够快速地溶解于溶剂中,最终实现快速、均质、安全塑化过程,为后工艺实现连续化生产、达到最佳产品质量提供可靠支撑。

Numerical simulation of solidification morphologies of Cu-0.6Cr casting alloy using modified cellular automaton model

The purpose of this study is to predict the morphologies in the solidification process for Cu-0.6Cr(mass fraction,%)alloy by vacuum continuous casting(VCC)and verify its accuracy by the observed experimental results.In numerical simulation aspect, finite difference(FD)method and modified cellular automaton(MCA)model were used to simulate the macro-temperature field, micro-concentration field,nucleation and grain growth of Cu-0.6Cr alloy using real data from actual casting operations.From the observed casting experiment,the preliminary grain morphologies are the directional columnar grains by the VCC process.The solidification morphologies by MCAFD model are in agreement with the result of actual casting experiment well.