Metallized, 3D-printed radiofrequency coils

Radiofrequency (RF) coils are central to nuclear magnetic resonance (NMR) performance, yet coil design is often constrained to a small number of well-established geometries that can be fabricated reliably using existing methods. Here, we present a practical approach for fabricating complex, high-performance RF coils using stereolithographic (SLA) 3D printing followed by copper metallization. A two-stage plating process produces mechanically robust, copper-coated coils with thicknesses exceeding multiple RF skin depths, enabling operation under the high-power conditions required for magic-angle spinning (MAS) solid state NMR. To fully exploit this fabrication approach, we developed a lightweight, quasi-static magnetic field modeling program that operates directly on 3D-printable coil geometries and enables numerical optimization of RF performance prior to printing and metallization. As a demonstration, we simulate and fabricate an optimized variable-pitch, tilted-helix solenoid for MAS solid state NMR that delivers a 24.3% increase in transverse RF field strength relative to a conventional fixed-pitch solenoid of similar dimensions. Spatially resolved nutation imaging further shows that this design extends the region of uniform excitation by 11.5%. Overall, this work advances RF coil development away from adapting experiments to fit canonical coil geometries, and toward designing coils that deliver strong, homogeneous RF fields for demanding and customized conditions.