The analysis of short shot possibility in injection molding process

Abstract

This paper presents the analysis of short shot possibility in injection molding. The aim of this research is to evaluate process and geometric parameters which increase the possibility of short shot in an injected part based on the proposed method. The analysis of short shot possibility was conducted via SolidWorks Plastics and Taguchi method for orthogonal array experiment of L18 to find the significant process and geometric parameters. Finite element method (FEM) is employed in SolidWorks Plastics for simulation. To validate the simulation result, an experimental study was conducted for two circular flat polypropylene of 1-mm thickness. Filling time, part cooling time, pressure holding time, and melt temperature were selected as process parameters, and gate type was selected as a geometric parameter. A new method of analysis for short shot defect is proposed herein to predict the possibility of short shot in injection molding before it occurs. The significance rate of each parameter in both experiments and simulation result was very close together which signifies the robustness of proposed method in evaluation of short shot possibility. Melt temperature was the most influential parameter with a contribution of 74.25 and 75.04%, and filling time with a contribution of 22 and 20.19% followed by gate type with a contribution of 3.69 and 3.93% for simulation and experimental results, respectively. Hence, based on response table of S/N ratio, the optimum levels of each parameter which leads to reduction in possibility of short shot are gate type at level 1, filling time at level 3, and melt temperature at level 3. Finally, melt temperature, filling time, and gate type considered as significant parameters which affect the possibility of short shot in injected parts.