The Evaluation of Mould Made from Aluminium and Mild Steel for Polypropylene Integral Hinges Test Samples

The purpose of this study is to evaluate the mould, which is made from mild steel and aluminium, and the effect of these moulds properties towards the quality of thermoplastics part. As for this research, two different types of mould material were fabricated by using Computer Numerical Controller (CNC) milling machine. These moulds were specifically design to produce a test sample which was an integral hinge made from Polypropylene. These moulds were tested practically by using Nissei-NP7-1F injection moulding unit. A set of parameter setting consisting of melt temperature, packaging pressure, injection time, packing time and mould temperature had been chosen to acquire the correlation between the mould materials and the part’s quality. Five tested samples were prepared for evaluation in terms of the material consumption, warpage, and shrinkage values. Results have been observed and analysed and it was found that in term of material consumption value, aluminium mould consumed 1.28 gram or 14% more polypropylene than mild steel. For warpage value, mild steel mould had the lowest value with only 0.08mm warpage. The third experiment showed that the lowest shrinkage was happened to be 0.01302, which was produced by mild steel mould. As the conclusion in this project, mild steel mould was selected as the desirable mould for producing integral hinges samples as compare with the aluminium mould.