Researchers in the EU RECOTRANS (Integrated manufacturing of REcyclable multi-material COmposites for the TRANSport sector) have used microwaves and laser welding to obtain recyclable composites for automotive and transport.

The project, led by AIMPLAS, is intended to help produce lighter and, therefore, less polluting vehicles without increasing costs. RECOTRANS researchers obtained a reduction in costs and energy consumption in the manufacture of three prototypes. They also confirmed the feasibility of recycling and processing the resulting material.

The researchers developed new thermoplastic composites through the integration of microwaves and laser welding. They demonstrated that microwaves can be used to optimize the curing process of composites in resin transfer moulding (RTM) and pultrusion, which reduces the energy consumed, shortens manufacturing times and helps produce better-quality parts. It has also been shown that laser technology can be used to obtain stable joints between the composite and metal, thus making it possible to do without riveted joints, which increase structural weight. Finally, studies were carried out on the recyclability of the thermoplastic composite by using it to manufacture a new part.

These results were validated through the manufacture of three life-size demo samples and one demo sample from the recycling material.

The demo sample of the rear suspension system of a truck cab was manufactured through the integration of microwaves in the RTM process to make a thermoplastic composite with glass fibre, thermoplastic acrylic resin and a composite-metal joint made using laser welding.

An automotive door panel was also manufactured by integrating microwaves in the c-RTM process to make a thermoplastic composite with carbon-fibre reinforcement and thermoplastic acrylic resin.

An interior panel was manufactured for the rail industry by using microwaves in the pultrusion process to make composites with glass fibre reinforcement and thermoplastic acrylic resin. The joint between the composite and metal parts was made using laser welding.

In addition, the recyclability of the materials was validated by manufacturing a demo sample of a car door handle made of 50% recycled material.

The RECOTRANS project, which started in October 2017 and ended this month, received funding from the European Union within the framework of the H2020 Programme. A total of 13 partners from seven countries have taken part: Stadler, Gestamp, Mercedes Benz Türk, Arkema, INEA, Tecnoclad, Synthesites, Far-UK, CTAG, ITU, Fraunhofer, Polymec and AIMPLAS. The developments made in this project can be applied to other industries.