Gate design and filling process analysis of the cavity in injection molding process

Abstract

This paper presents a new geometry of an edge gate in the injection molding process called modified edge gate. The corners of current edge gate result in the turbulence of molten plastic into the cavity which leads to internal and external defects. The aim of the new geometry is to reduce the internal and external defects of injected part such as sink marks and short shot. The easier de-gating analysis for the new geometry to decrease the visible blemish of the injected part was proposed in this study. A modified edge gate was proposed for two circular flat plates with thickness 1 mm. Finite element method (FEM) was used along with SolidWorks plastic. Internal and external defects of the injected part were analyzed via SolidWorks plastic. To validate the new geometry, an experimental study was implemented for two polypropylene (PP) circular flat plates with modified edge gate to confirm the simulation results. The contribution of this research is to modify the geometry of current edge gate by removing the corners of rectangular edge gate which leads to the reduction of scrap. The new geometry presents easier de-gating of gate and less visible blemish of the injected part. A smooth flow of molten plastic into the cavities reduces the internal and external defects. The outcome of this study demonstrates filling of the cavities with no short shot. In addition, no sink marks were detected with modified edge gate. Finally, the modified edge gate has less visible blemish on the injected part in comparison with current edge gate.

Keywords

Injection molding / Gate design / Internal defects / External defects