SMART4CAR – Smart Surfaces for Automotive Components, is a co-promotion project, within the scope of the Bosch Suppliers Club, whose consortium is formed by InovePlastika – Inovação e Tecnologia em Plásticos S.A, a business promoter, with extensive experience in the development and production of injected components. of added value, the PIEP – Centre for Innovation in Polymer Engineering, University of Minho, the CENTITVC – Centre for Nanotechnology and Technical, Functional and Intelligent Materials, and the INL – International Nanotechnology Laboratory. Subsequently, this R&DT project aims to develop a solution that includes the incorporation of decorative, functional, and interactive properties during the injection molding process (Figure 1).

Figure 1.  Integration of IME in the over-moulding process for the production of controls on the central panel of the car cabin, which includes the incorporation of decorative, functional, and interactive properties (Illustrative image (Renders).

One of the great challenges present in the project is the incorporation of a single film, with electronics and with the decorative pattern, which will allow a considerable reduction of process steps as well as the minimization of associated raw material or the introduction of secondary decorative processes. In this way, it is extremely important to ensure the integrity and survival of all electronic components throughout the processes to which they are subject. During injection molding, these components can suffer degradation or displacement, due to high temperatures, high pressures exerted, and high shear rates. This process requires specially selected films and inks. Factors such as compatibility between materials, film thickness, formality, and temperature resistance of the paint and films, have to be carefully considered in the material selection stage so that the final part has the quality and meets the requirements of the automotive industry.

By performing numerical simulations of the injection moulding process, it was possible to define the location of the molten material inlets, in positions in order to guarantee the survival or minimization of the effects of shear rates and the degradation of electronic components. Through the simulation, it was also possible to predict areas in which the film would have a greater probability of melting, and perhaps, suffering drag. This function made it possible to predict defects and correct them before the actual process (Figure 2).

Figure 2.  Prediction, through the numerical simulation of the process, of areas of the film that may melt or cause its drag during the injection.

This is a critical step, and it can jeopardize all the work previously carried out. The numerical simulation also allows for effective analysis and selection of the most suitable temperature control system for the injection mold. With the use of this methodology, it is possible to verify the efficiency of the cooling system, the layout of the system, and the required cooling time, taking into account the incorporation of the film in the process that causes a different distribution of temperatures on both sides of the part (Figure 3).

Figure 3.  Asymmetric temperature prediction during cooling is caused by the incorporation of the film in the process.

The selection of the most suitable processing conditions for the component in question, in order to reduce, for example, the warping of the part can, in a similar way, be defined. As obvious advantages of this methodology, there is not only a reduction in raw material (scrap), but also a reduction in the time spent on machine hours, and energy in obtaining parts in accordance with the requirements and specifications intended.

The project will demonstrate technological progress in this field, thus allowing the consortium and the national industry the opportunity to reposition themselves in the global value chain of the automotive industry and, also, allow the easy industrialization of the technologies described.

Work carried out within the framework of the SMART4CAR project, POCI-01-0247-FEDER-045096, financed by the European Regional Development Fund (ERDF) through the Operational Program PO North.