Compact, magnetically actuated, additively manufactured pumps for liquids and gases

Abstract

We report the proof-of-concept demonstration of novel, valve-less, and magnetically actuated miniature (∼1 cm3) positive displacement pumps for liquids and gases—both single-material-printed pumps with embedded sintered magnets and the first monolithic, fully 3D-printed, multi-material magnetic pumps in the literature; a valve-less design greatly simplifies the pump’s operation and consumes less power compared to designs with active valves, and is less prone to clogging than designs with passive valves. The miniature diaphragm pumps are fabricated using 150 μm-thick to 225 μm-thick layers via fused filament fabrication; the structural parts are printed in pure Nylon 12, while the magnet that makes possible the actuation of the pump chamber is either monolithically printed in Nylon 12 embedded with NdFeB micro-particles or press-fit into the pump after single-material printing of the enclosing piston. The fabrication of the pumps employs a novel multi-material-compatible 3D printing process flow that monolithically creates all features with less than 13 μm of in-plane misalignment. Pump fabrication takes below 75 min to complete and costs under $3.89 in materials. The devices are driven by a rotating magnet and can deliver liquid flow rates as large as 7.88 ml min−1 at 198 Hz for sintered magnet pumps (N35 grade) and 1.68 ml min−1 at 204 Hz for the devices with monolithically 3D-printed magnets (∼N4 grade); the results surpass state-of-the-art, 3D-printed miniature liquid pumps. Actuation of a pump in excess of 14.4 million cycles shows no evidence of degradation, e.g. leaks. A pump with sintered magnet (N48 grade) was characterized as a vacuum pump using air as working fluid, achieving an ultimate pressure of 540 Torr in a 0.61 ml pumping volume and up to 9.3 ml min−1 flow rate at 230 Hz actuation; the results compare well with miniature, commercial, non-3D-printed vacuum pumps.