One of the key concepts of Industry 5.0 in the plastics production chain is the introduction of new, more sustainable, biodegradable, or compostable materials, as well as high-performance materials for the development of more durable and lighter products. Across the board, companies have made evident their efforts to utilize recycled materials, both post-consumer and closed-loop, through the recovery of material from the process (purges, setup, etc.). These materials are then combined with the application of advanced injection technologies to overcome process, design, or material limitations in the production of increasingly complex products with more stringent requirements, exceeding the expectations of an increasingly demanding market while minimizing the environmental impact of their processes and products. The introduction of solutions that go beyond the state-of-the-art dictates the market positioning of companies in the national industry and enhances their position in the global market, contributing to competitiveness and internationalization [5]. Thus, the injection systems paradigm has been enriched by new trends, notably the use of technologies such as gas- or water-assisted injection, which aim to reduce raw material consumption and improve the weight-to-strength ratio of the parts produced. This process involves introducing an inert gas (usually N2) or water into the molten polymer to create internal cavities during the injection molding cycle, resulting in the production of hollow parts with optimized material distribution and reduced shrinkage and warpage [6].

Another alternative is Foam Injection Molding (FIM), which involves incorporating a blowing agent (physical or chemical) into the molten polymer, resulting in parts with an internal cellular structure [7]. The introduction of blowing agents creates a microcellular structure within the part, reducing density and, consequently, weight to achieve specific mechanical properties [8]. PIEP, as a scientific and technological entity, has sought to leverage the development of its capabilities with a vision for a greener and more sustainable future. As part of the European VITAL project, under the Horizon Europe Framework Programme (HORIZON) [9], PIEP has led the study of developing microcellular foams using thermoplastic materials and bio-based blowing agents, with a special emphasis on the automotive and consumer (appliance) sectors. Projects like VITAL demonstrate how new technologies can be applied to optimize injection processes and product circularity. The use of recyclable or biobased materials, along with manufacturing technology, contributes to reducing waste compared to traditional injection solutions.

Despite the advantages of using technologies such as FIM, combining them allows for improved injection process control and optimized part quality. Gas Counter Pressure (GCP) is a complementary technology that can be applied particularly to parts with complex geometries or stringent requirements [10]. In this specific case, applying internal pressure to the cavity helps stabilize the part during injection to address issues such as filling failures and enables more uniform parts [11]. Thus, the combination of these two technologies translates into a holistic process approach, enabling higher-quality parts (surface finish, structural uniformity, and strength), opening up a new range of applications for the plastics industry. As part of Activity 3 of the internal Polarise project, part of the development of new skills and capabilities, PIEP intends to combine FIM and GCP. Exploring the synergies between FIM and GCP opens up new possibilities for product design and expands the introduction of new functionalities, providing a new opportunity for the thermoplastics industry.

Regarding different plastic part production technologies, multicomponent injection is also identified as a trend. This technology enables the multimaterial and multifunctional production of parts, combining the properties of different materials in a single production step, either through multimaterial injection or by integrating inserts or films into the mold cavity. This increases design flexibility and reduces, or even eliminates, post-assembly, adhesion, or welding processes [6].

The advancement of injection systems can therefore prove to be a strategy for the competitiveness of mold and plastics companies. However, despite the advantages associated with these technologies, companies in the industry face several challenges in adopting them, including high investment in infrastructure and qualified professional training, as well as the modernization of production processes and/or cultural adaptation within companies. Thus, collaboration between innovation centers like PIEP, which has been acquiring expertise in this area, and industry can accelerate the implementation of new technologies, the digitalization of processes, and the development of new materials, helping the sector align with global trends.