The increase in waste has motivated the adoption of the circular economy concept, which assumes particular relevance in the case of plastic materials. This has led to research of new possibilities for recycling plastics after their end-of-life. To achieve this goal, it is fundamental to understand how the materials’ properties change after recycling. This study aims to evaluate the thermal and mechanical properties of recycled plastics, namely polycarbonate (PC), polystyrene (PS), glass fibre-reinforced polyamide 6 (PA6-GF30), and polyethylene terephthalate (PET). With this purpose, injected samples were mechanically recycled twice and compared through thermal and mechanical tests, such as differential scanning calorimetry, hardness, tensile strength, and the melt flow rate. The results show that the amorphous materials used do not suffer significant changes in their properties but exhibit changes in their optical characteristics. The semicrystalline ones present some modifications. PET is the material that suffers the biggest changes, both in its flowability and mechanical properties. This work demonstrates that the mechanical recycling process may be an interesting possibility for recycling depending on the desired quality of final products, allowing for some materials to maintain comparable thermal and mechanical properties after going through the recycling process.

Plastic waste is increasing, and a strategy to reduce it is needed to minimize the integration of virgin raw material in the production of parts

Adjusting the contact surfaces, or interferences, in an injection mold is a critical process that can affect the performance of the mold and the quality of the molded parts. This process often involves high impact loads, especially for large molds that involve large masses of inertia in motion and generate significant kinetic energy during mold closure. Impact forces can propagate through the mold structure causing damage to the tool, mold, or even the injection equipment where the mold is placed, causing operational errors due in particular to system vibrations. This study evaluates impact forces during mold closure using numerical simulations in ANSYS, focusing on the mold’s fixed part and its support structure. Results demonstrate that integrating energy-absorbing elements significantly reduces transmitted impact energy without compromising stability. This approach enhances safety and efficiency by minimizing vibrations and protecting machinery.

This work aims to study the injection of molded optical components for the automotive industry produced by an injection molding plastic company