Geometrical Parameter Optimization of Circular Cross-Section Conformal Cooling Channels in Injection Molds of Plastic Paving Block Molds

Abstract

High productivity and product quality are sought after by manufacturers due to the increasing demand for and use of plastic items. Injection molding is the most famous method used to make majority of the plastic items. Injection molding is however known for its lengthy production durations and poor product quality. This study shows the optimization of multiple design characteristics of circular cross-sectioned conformal cooling channels in response to reducing production time while improving product quality, at the same time, using Taguchi design-of-experiments approach. Diameter, depth, and pitch were the three main design variables examined. A Computer Aided Design software was used to create three dimensional designs and to conduct simulations. The responses obtained from simulations were time for cooling to ejection temperature, overall product shrinkage, extents of warpage and dimensions of sink marks. These output parameters were taken as input variables for multi-response optimization utilizing the method of Taguchi Grey Relational evaluation. The outcome obtained revealed that the minimum design variables resulted in the concurrent minimization of all responses for the particular geometry studied. Study of variance showed that the diameter to be the design factor that most significantly influenced all the responses simultaneously. Additionally, it was shown that conformal cooling channels yield better production outcomes than straight cooling channels whereby they gave the minimum cooling time and product defects. The optimized conformal cooling channels, when compared with straight cooling channels, reduced the time to cool the product, product shrinkage, dimension of warpage, and extent of sink marks by 29.35%, 5.99%, 19.77%, and 38.85% respectively.