In-House Fabrication of 1.3 to 7 mm MAS Drive Caps using Desktop 3D Printers

The 3D-printing technology has emerged into a well-developed method to fabricate parts with considerably low cost and yet with high precision (< 100 um). It was shown in the recent literature that the 3D-printing technology can be exploited to fabricate magic-angle spinning (MAS) system in solid-state nuclear magnetic resonance (NMR) spectroscopy. In particular, the 3.2 mm MAS drive caps with intricate features are well fabricated using an outsourced 3D printing service, and the caps were demonstrated to spin > 20 kHz. Here, we show that not only lab-affordable benchtop 3D printers can produce equal-quality drive caps as the commercialized version, but also smaller 2.5 mm and 1.3 mm MAS drive caps—despite slight compromise in performances. All in-house fabricated drive caps (1.3 to 7 mm) can be consistently reproduced (> 90 %) and achieved excellent spinning performances. In summary, the > 3.2 mm systems have similar performances as the commercial systems, while the 2.5 and 1.3 mm spun up to 26 kHz  2 Hz, and 46 kHz  1 Hz, respectively. The low-cost and fast in-house fabrication of MAS drive caps allows easy prototyping of new MAS drive cap models and, possibly, new NMR applications. For instance, we have fabricated a 4 mm drive cap with a hollow center to allow better light penetration or sample insertion during MAS.