聚合物异型材气辅口模挤出成型气辅滑移对异型材挤出胀大的影响

Effects of Gas-assisted Slip on Extrusion Die Swell of Gas-assisted Die Extrusion Process of Polymeric Profiles

基于流变学和流体动力学理论,经合理假设,建立了描述异型材气辅口模挤出成型过程的三维等温黏弹性理论模型,并通过 DEVSS/SUPG、最小元法 Mini-Element 和罚函数法等稳态有限元技术,建立了与该模型相适应的快速收敛的稳态有限元数值算法,并以此通过有限元数值模拟,系统研究了聚合物异型材气辅口模挤出成型过程的机理。研究结果表明:在异型材的挤出成型过程中,随着滑移系数的增大,离模膨胀也增大。聚合物异型材气辅挤出成型能基本消除挤出成型中的离模膨胀和翘曲变形。同时,解决了由于离模膨胀和翘曲变形引起的挤出口模难于设计的技术难题。

Based on theories of rheology and hydrokinetics, under reasonable assumptions, a three dimension isothermal viscoelastic model was formulated for the characteristic of the gas assisted die extrusion process of polymeric fluids. The corresponding stable numerical algorithm with fast convergent was established using stable finite element techniques in the DEVSS/SUPG method, Mini-Element method, and penalty function method, etc. Through the finite numerical simulation code of above scheme, the gas-assisted die extrusion molding mechanism of polymeric profile was systematically studied. Research showed that die swell increased with increasing slip coefficients and the gas-assisted full slip extrusion molding process of polymeric profile could almost eliminate extrusion die swell and warpage. At the same time, the technological difficulties caused by extrusion die swell and warpage could be solved in the design of an extrusion die.