Integrating flexible electronics into injection over-molded parts can be used to fabricate lightweight structural components with integrated functionality (e.g. sensor, structural health monitoring, display). In the interreg project “Flexlines”, Brightlands Materials Center has developed optimized methodology and suitable tooling with its partner (Holst Center, the Netherlands and imec, Belgium) regarding to integrate different types of flexible electronics into injection over-molding process with different engineering thermoplastics. The product produced from such technology is able to fulfill structural application, meanwhile the integration between flexible electronics and engineering thermoplastic is realized by optimized adhesion to enable a reliable long term performance and a significant product design freedom.
The complete process of design and fabrication of injection over-molded flexible electronic demonstrator is illustrated this video. The total injection over-molding cycle time of the demonstrator fabrication is less than one minute. Advanced simulation technology has been employed in predicting the temperature and stress profile of electronics during the injection over-molding process to optimize the tooling and flexible circuit design. In addition, the methodology is optimized to be applied with different types of flexible foil and engineering thermoplastics as illustrated in the following figure:
Polycarbonate (PC) injection molding compound over-molded on polyethylene naphthalate (PEN) flexible electronics.
Polyamide (PA) injection molding compound over-molded on polyethylene naphthalate (PEN) flexible electronics.
Polycarbonate (PC) injection molding compound over-molded on polycarbonate (PC) flexible electronics.
Polyamide (PA) injection molding compound over-molded on polyimide (PI) flexible electronics.
The long-term performance of over-molded flexible electronics have been evaluated by accelerated environmental aging test. It is observed that the functionality and adhesion can be maintained after ISO 16750-4 standard test (Aging samples under 80 °C/-40 °C fluctuations for 30 cycles) and AEC-200 standard test (aging samples under 85°C/85% RH for 1000 h, which equals to approx. 25-35 years in 35°C/60% RH).
For more information about this project visit the Flexlines website.