Minimizing Warpage and Shrinkage of Plastic Car Rear Bumper Fabrication via Simulation Based Optimisation

Abstract

Abstract Car bumpers are designed to absorb small impacts, such as accidentally bumping into another car while backing off a parking spot, not major road accidents. As to make it lighter, plastic is the best available material. To fabricate it by injection molding, thin-wall and complex parts such as car bumper might create a lot of defects such as shrinkage and warpage. So, the stronger plastic material and correct optimized parameters should be applied. Butadiene Styrene (ABS) is selected in this study. This project aims to optimize the injection moulding process parameters of plastic car bumper by using Central Composite Design (CCD) in Response Surface Methodology. Mould temperature, melt temperature, injection time are selected as factors to be studied. As the results, the optimum values suggested by the software were mould temperature of 25°C, 226.36°C melt temperature and 1.88s injection time. The best material suggested is ABS. With small differences in error value between solution and simulation, 0.895% of shrinkage and 10.3% for warpage, the results were acceptable.