Simulation of Stress Distribution near Weld Line in the Viscoelastic Melt Mold Filling Process

Binxin Yang,Jie Ouyang,Fang Wang

doi:10.1155/2013/856171

Abstract

Simulations of interface evolution and stress distribution near weld line in the viscoelastic melt mold filling process are achieved according to the viscoelastic-Newtonian two-phase model. The finite volume methods on nonstaggered grids are used to solve the model. The level set method is used to capture the melt interface. The interface evolution of the viscoelastic melt in the mold filling process with an insert in is captured accurately and compared with the result obtained in the experiment. Numerical results show that the stress distribution is anisotropic near the weld line district and the stress distribution varies greatly at different positions of the weld line district due to the complicated flow behavior after the two streams of melt meet. The stress increases quickly near the weld line district and then decreases gradually until reaching the tail of the mold cavity. The maximum value of the stress appears at some point after the insert.

Highlights

The plastic mold filling process produces large numbers of parts of high quality
Simulations of mold filling process mostly used the Hele-Shaw model coupled with the finite element method, which is based on the creeping flow lubrication model [1,2,3,4]
These papers studied the problem with only viscoelastic fluid phase considered and the gas phase in the cavity ignored, in which case complex boundary conditions must be properly dealt with

Summary

Introduction

The plastic mold filling process produces large numbers of parts of high quality. Plastic material in the form of granules is melted until it is soft enough to be injected under pressure to fill a mold. Many papers studying mold filling process coupled with interface tracking techniques can be found [11,12,13,14,15,16,17,18,19,20] In these papers, the viscoelastic properties of materials were ignored. Yang et al [23] proposed a model for mold filling process in which the governing equations for the viscoelastic fluid (melt phase) and the Newtonian fluid (gas phase) are successfully united into a system of generalized Navier-Stokes equations, avoiding dealing with complex boundary conditions. This paper uses the viscoelasticNewtonian two-phase flow model established in [23] and finite volume method on nonstaggered grids to study the mold filling process with an insert in the cavity and analyze the stress distribution near the weld line.

Numerical Methods

Numerical Results and Analysis

Conclusion