Optimization of polygonal cross-sectioned conformal cooling channels in injection molding

Abstract

In injection molding process, cooling time accounts for up to 80% of the whole cycle time, and this has a significant effect on productivity. Cooling time can be reduced by use of cooling channels in molds. This paper presents a study on optimization of conformal cooling channels with various cross-sectional shapes, depths, and pitches. The depth of sink marks, volumetric shrinkage, warpage, and cooling time, are estimated using Solidworks Plastics 2021® using Taguchi design of experiments. Simulations on cooling time were carried out for a mold with straight cooling channels and experiments were carried out to verify the simulation results. Simulations were then carried out on molds with conformal cooling channels and the results were analyzed using Analysis of variance, principal component analysis, and grey relational analysis. It is seen that the multi-response Taguchi-Grey optimization method is suitable for the selection of the best cooling channel design. It is further seen that the shortest cooling time with smallest product defects can be achieved through the use of a cooling channel with a decagonal cross-section and a depth equal to the pitch. Moreover, pitch is the most critical factor influencing sink marks, shrinkage, warpage, and cooling time concurrently