In recent years, injection moulding process is one of the most advanced and efficient manufacturing processes for mass production of plastic bottles. However, a good quality of parison is difficult to achieve due to uncontrollable humidity, pressure inlet and water inlet velocity. This paper investigates the effect of using multiple mould cavities to improve the process fill time and injection pressure in the production of PET plastic bottles using MoldFlow software. The modelling of parison was developed using CATIA with the consideration of every part of the parison. MoldFlow software was used to analyse the flow of 20 g parison with different cavity numbers (1, 8, 16, 24 cavity), as well as its corresponding runner size towards its fill time and injection pressure. Other important parameters that affect the production of parison, such as melting temperature, mould temperature, atmospheric temperature and cooling time, were remained constant. The fill time required to produce 24 moulds was improved by 60% compared to using 8 mould cavity only, and this enable the production of more plastic bottles in a day. Therefore, fill time and injection pressure are two important parameters to be considered in the injection moulding process, especially to reduce parison defect and increase its production rate.
The study aims to investigate the effect of injection moulding parameters on plastic flows behaviour of the multiple-cavity polyethylene terephthalate (PET) cylindrical containers via injection moulding process. The motivation of this study is to present an alternative manufacturing solution to make cylindrical type containers that are commonly used in packaging beverages, such as the 330 ml standard size for packaging carbonated soft drink. The PET cylindrical container was modelled using CATIA drawing software and the injection moulding simulation process was done via Moldflow software. The investigation was done by varying two significant moulding parameters; the material melt temperature and the mould temperature. The effects of these two parameters on the PET plastic flow behaviour were studied. In particular, the simulations of the model were analysed and focused on the mould filling time as well as the moulded PET cylindrical container’s shrinkage occurrence. Three types of mould cavities structure were understudied; single-cavity, four-cavity and eight-cavity. Results show that the eight-cavity mould yielded higher production rate. The simulation results indicated that the production rate of 4-cavity and 8-cavity mould increased by 258.5% and 578.8% respectively. It was observed by increasing the melting temperature, the mould filling time is shorter and as a result, the production rate has increased by 7.75% per °C. But with this Mouldflow setting, the volumetric shrinkage and the maximum deflection have been significantly affected; increased by 23.15% and 29.26% respectively. The mould filling time and maximum deflection did not show a steady trend line however, the volumetric shrinkage increased by 7.28% per °C.