Hybrid Additive Manufacturing Method for Selective Plating of Freeform Circuitry on 3D Printed Plastic Structure

This work proposes a hybrid additive manufacturing method coupling the advantages of dual-material fused deposition modeling (FDM) 3D printing and selective electroless plating. The method relies on the selective sensitization/activation and metallization of dual-material FDM 3D printed structure. High-conductive nickel alloy can only be deposited on the platable plastic surface leaving the nonplatable plastic bare. The study reveals that a combination of acrylonitrile-butadiene-styrene and polyethylene terephthalate glycol-modified materials provides the best metallization selectivity and film adhesion strength. The effects of electroless plating parameters such as temperature, pH value, and duration on the electrical conductivity of metallic film are systematically investigated. Through four-point probe measurement, energy-dispersive X-ray spectroscopy inspection, and scanning electron microscopy cross-section analysis, it is found that the metal deposition rate majorly depends on the plating temperature, while the composition of plated film is mainly determined by the pH value. Thus, the conductivity of metallic film can be customized according to the detailed requirements of practical applications. A minimal resistivity of 6.7 x 10(-5) Omega cm is obtained when electrolessly plated at 50 degrees C and pH 9. A light-emitting diode (LED) blinking circuitry is fabricated in both 2D and 3D manners as demonstrators to prove the feasibility and potential of this technology in industry applications.