Injection moulding is the most commonly used process for making complex plastics products in many fields and warpage is a major defect in injection moulded part especially for thin-shell parts. Therefore, the key to improving the part quality is by finding a solution to reduce the warpage. A three-pin terminal cover of an electric kettle which made of Polypropylene (PP) material was used in this research as thin shell plastic part. The simulation software which is Autodesk Moldflow Insight 2012 (AMI) used in this research to identify the recommended process parameter settings. Therefore, most significant parameters in reducing warpage formation on thin shell part are packing pressure, packing time, melt temperature and cooling time chosen, based on the previous study. Response Surface Methodology (RSM) has been applied in this study to find out the significant parameter in the injection moulding process and recommended settings in minimizing the warpage value. The most significant factors that influence the formation of warpage in thin shell part is packing time and melt temperature for y-axis and the z-axis direction, respectively. From this study, the formation of warpage has been improved by 19.79% for y-axis direction and 11.80% for z-axis direction using RSM optimisation method compared with recommended process parameter settings that obtained from AMI.
