Fully automated innovative cell for the union of multimaterial automotive parts

Driven by the increasingly stricter limitations related to fuel consumption and the reduction of emissions, many car manufacturers are working on lightening strategies. Following the right material, in the right place mantra, the current tendency combines different materials to create components with enhanced properties: On one hand, the composites reinforced with fibreglass or carbon add flexibility and lightness, whilst the metals guarantee the necessary structural resistance, resulting in an optimised performance/cost ratio.

To ensure the reliability in the union of these combinations of materials, at TECNALIA we have developed the first fully automated demonstrator cell for the union of multi-material plastic-metal parts that do not add weight to the final component, in conjunction with IVW, Gübesch, EDAG, LTAG, CRF, NIT, Fraunhofer ILT, KGR and FILL.

This technology enables the weight of the final component to be reduced by up to 20%, hence reducing both manufacturing costs through less rejections, and the environmental impact thanks to the use of thermo-plastic materials that are easily repairable and have a recycling capacity, through the application of heat. It is a development carried out within the framework of the H2020 Flexhyjoin European project.

The Cell integrates a surface treatment system that uses laser technology to generate micro-cavities in the metal part into which the melted plastic can be introduced, increasing the resistance of the union thanks to the creation of mechanical interlocks. The control and supervision system of the laser and induction union system, implemented by TECNALIA, supervises and controls the critical variables of the laser union process in real time (temperature and tooling force) which guarantees that they remain in the optimum window, increasing the reliability of the process in question.

Furthermore, it allows flaws to be detected based on non-destructive testing techniques through the application of lock-in thermography and the development of automated analysis methods, which classifies the quality of the union.