사출압축성형 공정의 3차원 수치적 해석

Abstract

Injection-compression molding (ICM) process, combining conventional injection molding (CIM) process with compression molding, is widely used in manufacturing of optical media and optical lenses. Although a number of numerical studies regarding ICM process has been carried out by few research groups, most of them employ Hele-Shaw approximation, which is appropriate for thin cavity geometry only. In this regard, this work presents a three-dimensional numerical analysis system of ICM process using a stabilized finite element method (FEM) and an arbitrary Lagrangian-Eulerian (ALE) method. The developed system is verified by comparing the results with existing experimental data as well as simulation data obtained from commercial software. Then, the system is adopted for simulations of ICM process of an optical lens, which is a practical example of three-dimensional geometry. The results are first compared with that of CIM process, showing that ICM process results in reduced and more uniform distributions of pressure, generalized shear rate and shear stress of the final part. Basic parametric studies are also carried out to understand effects of processing conditions during compression stage, such as compression velocity and compression gap. It is observed that the gate pressure, generalized shear rate and shear stress during injection stage are affected by compression gap, whereas compression velocity affects those values during compression stage.