Integration of electronic components in the thermoplastic processing chain: Possibilities through additive manufacturing using conductive materials

An alternative approach for the production of Molded Interconnect Devices (MID), using additive manufacturing of thermoplastics, is presented. Two-component 3D printing enables the processing of a pristine polymer together with a second phase composed out of conductive nanocomposite. For the validation of this concept, two different demonstrators were developed and produced using an Arburg Freeformer printer: a USB insert with an integrated LED ("Lightstick") and a capacitive touch sensor system. The conductive paths were printed in PC/ABS made conductive with carbon nanotubes (CNTs). Measured resistivity of each conductive layer, of 200mm thickness, was of 1 Ocm. The whole circuit resistance together with the contacts has proved to be low enough to successfully light up the LEDs. Furthermore, printed capacitive electrodes demonstrated that the functions of touch pad, proximity sensor and slider can be integrated in a thermoplastic without additional metallic components. This technique presents promising results for the integration of electrical functionality into thermoplastic parts and their processing chain.