Warpage optimisation on front panel housing using straight drilled and conformal cooling channels in injection moulding process

Nowadays, there are various optimisation methods that have been explored by researchers to determine the appropriate setting of processing parameters in the injection moulding process. Based on previous researches, the use of optimisation works has improved the quality of the moulded part produced. Apart from quality, the productivity in the injection moulding process also plays an important role. Therefore, some researchers and manufacturers have introduced the application of conformal cooling channels in injection process which have been proven to improve the quality and productivity of the moulded part due to better uniformity of temperature distribution in the mould as compared to the conventional straight drilled cooling channels. However, the application of optimisation techniques to determine an appropriate setting of processing parameters in previous researches were mainly focused on the conventional straight drilled cooling channels, whereas in conformal cooling channels is still lacking due to the difficulties in mould fabrication. In this study, the application of optimisation technique to improve the warpage on the front panel housing using the conventional straight drilled and Milled Groove Square Shape (MGSS) conformal cooling channels was explored. Simulation studies using Autodesk Moldflow Insight (AMI) 2013 software were conducted to obtain the recommended processing parameters for both types of channels. Then, by selecting cooling time, coolant temperature, packing pressure and melt temperature as the variable parameters, Design of Experiment (DOE) has been constructed using the face-centered, Central Composite Design (CCD) approach. Response Surface Methodology (RSM) was performed to develop mathematical models to employing Glowworm Swarm Optimisation (GSO) and Genetic Algorithm (GA) optimisation approaches in order to determine the appropriate setting of the processing parameters to optimise the warpage defect. Results from experimental works showed that, the performance of MGSS conformal cooling channels is remarkably improved in terms of quality and productivity compared to the straight drilled cooling channels before and after optimisation. GA offers the lowest warpage value, followed by RSM and then GSO for both types of channels. The warpage on the front panel housing was improved by 32.5% (from 0.375 mm to 0.253 mm) and 22.9% (from 0.205 mm to 0.158 mm) using straight drilled and MGSS conformal cooling channels respectively after optimisation using GA, compared to the recommended setting suggested from simulation studies. Next, it was followed by an RSM approach with the improvement of 30.7% and 22% using straight drilled and MGSS conformal cooling channels respectively as compared to the recommended setting suggested from simulation studies. Lastly, the result using GSO approach showed an improvement of 18.7% and 7.3% using straight drilled and MGSS conformal cooling channels respectively when compared to the recommended setting suggested from simulation studies. Therefore, it can be suggested that, this research provides beneficial scientific knowledge and alternative solution for plastic injection moulding industries to enhance the quality of the moulded parts produced using optimisation techniques.