Controlling the EMI Shielding Properties of Conductive Fused Deposition Modeling Material

Recently, 3D printing has become more popular due to the availability of new materials. For example, electrically conductive graphene-PLA composites can be used as a shield for electromagnetic interference (EMI); specifically, circuit packages 3D printed using conductive composites could provide shielding. The purpose of this research is to determine how the parameters of 3D printed samples impact the shielding effectiveness. Our previous research has shown that the percentage and orientation of infill has the greatest impact on conductivity. Here, we test shielding effectiveness from 10 MHz to 3 GHz by measuring RF transmission through a sample by sandwiching it between a custom coaxial tester connected to a spectrum analyzer. The data showed that the greater the infill percentage, the less the orientation effects attenuation. For example, 100% infill samples with perpendicular and parallel orientation both attenuated by -15 dB at 1 GHz. However, at lower infill percentages, more varied infill orientations differed in RF attenuation. For example, at 25% infill, samples with perpendicular and parallel infill attenuated by -20 dB and -12 dB at 1 GHz, respectively. The most efficient sample by mass had 25% infill orientated at 4 varying angles.