In today’s manufacturing industry, plastic injection moulding is widely used, both locally and worldwide.

In 2021, the global injection moulding industry was valued at €220.5 billion, with an expected CAGR of 4.6 per cent from 2022 to 2030 (‘Injection Molding Machine Market Size & Share Report, 2030’. https://www.grandviewresearch.com/industry-analysis/injection-molding-machine-market, accessed on September 2, 2022).

It owes its popularity to its relatively large-scale application in the mass manufacturing industry, being capable of producing large quantities of plastic parts to consistent quality.

Injection moulding is a process in which molten plastic is pressurised to fill mould cavities and is then cooled down to produce plastic products for various applications. Due to the nature of this process, issues relating to air entrapment in the mould cavities are very common, resulting in a variety of part defects such as incomplete cavity filling, burn marks and high residual stress in the moulded products which in turn will result in waste which has its own financial and environmental implications.

To solve such issues, primarily related to incomplete mould filling caused by air traps, injection moulding machine operators increase the injection pressure to promote a more complete cavity filling. Even though the part dimensions could be accurately achieved, this is an unsustainable solution as it causes low quality products due to the high residual stresses in the plastic parts.

Moreover, such a practice requires higher energy consumption incurred by increasing the injection pressure especially when mass producing thousands or millions of components.

One other solution is the implementation of an active vacuum venting system which removes air from the mould prior to the injection of the melt. However, all active vacuum venting systems currently available on the market are bulky and costly as well as labour-intensive in terms of mould design and manufacture.

Therefore, a novel active vacuum device called VacuUM was innovated by Dr Arif Rochman from the Department of Industrial and Manufacturing Engineering (DIME) at the University of Malta (UM).

VacuUM will offer a cost-effective solution capable of solving even extreme air trap problems and thus encouraging a proper cavity filling for a much lower injection pressure.

In doing so, the energy consumption and the scrap rate will be reduced, and part quality is elevated. Dr Ing. Paul Refalo will greatly contribute to this project in sustainability analysis of the injection moulding process without and with the VacuUM device. Sarah Mifsud is the research support officer of this project and has also embarked on her PhD studies. To successfully achieve the goal of the VacuUM project, UM is collaborating with Toly Products Ltd, represented by Olaf Zahra (chief officer technology and sustainability) and Tayebeh Sepasi, due to their relatively high number of injection moulding machines and their continuous efforts in improving the sustainability of their manufacturing processes.

The VacuUM project is led by the University of Malta and is funded by the Malta Council for Science and Technology (MCST) through its FUSION R&I Technology Development Programme (R&I-2020-004-T).