Evaluation of electromechanical impedance, modal and X-ray testing as non-destructive methods for additively manufactured plastics

Additively manufactured plastic parts often contain defects that compromise structural integrity. This study compares three complementary non-destructive testing (NDT) methods X-ray, modal analysis and Electromechanical Impedance (EMI). A three‑tiered inspection workflow is proposed: Digital X‑ray radiography localises any residual sub‑surface discontinuities with sub‑millimetre precision and records volumetric morphology for traceability. Vibration‑based modal metrics then interrogate the full component and quantify shifts in global stiffness and damping that betray larger, oriented, or through‑thickness flaws; finally, Electromechanical Impedance (EMI) supplies rapid, on‑printer screening that highlights localised stiffness losses or weakly bonded layers within seconds high‑resolution Although X‑ray imaging, serving as the reference method, provides spatial information on internal flaws, its effectiveness is limited for detecting defects smaller than <1 mm in length. This work advances the understanding of how different NDT methods can be integrated to enhance reliability in plastic additive manufacturing, offering practical insights into defect orientation effects and detection thresholds.