Harvard College

Massachusetts Institute of Technology

The General Hospital Corporation

Thomas J Ober

Jennifer Ann Lewis

Mehmet Toner

Gareth H McKinley

Eugene J Lim

A microfluidic printing nozzle for 3D printing may include a mixing chamber, a first inlet for connecting with a first ink source, the first inlet located at a first end of the mixing chamber, and a second inlet for connecting with a second ink source, the second inlet located at the first end of the mixing chamber. An outlet may be located at a second end of the mixing chamber, and a generally cylindrical impeller may be rotatably disposed in the mixing chamber between the first end and the second end. The cylindrical impeller may include an outer surface, and the outer surface of the impeller includes a groove, a protrusion, or both, to facilitate mixing of fluidic inks flowing from the first end to the second end of the mixing chamber.

Microfluidic active mixing nozzle for three-dimensional printing of viscoelastic inks

One example of systems and methods for inertio-elastic focusing of particles in microchannels includes a substrate including a channel having an inlet and an outlet. A viscoelastic fluid, i.e., a fluid having a dynamic viscosity that varies with shear rate, and that carries suspended particles is driven through the channel. The volumetric flow rate at which the fluid is driven results in the formation of a localized pathline in the fluid at or near a center of the channel. The localized pathline defines a width that is equal to or slightly greater than a hydraulic diameter of the particle. The particles in the fluid are focused into the localized pathline.

Inertio-elastic focusing of particles in microchannels

The present disclosure relates to a device for three-dimensional ink deposition from an impeller-driven active mixing microfluidic printing nozzle. The device is configured to receive a material property associated with the plurality of fluids and receive a structure property of the printing nozzle. The device then determines a threshold relation between a rotating speed &#x3a9; of an impeller in the nozzle and a volumetric flow rate Q of fluids that flow through the nozzle based on the material property of the plurality of fluids, the structure property of the printing nozzle. Based on the threshold relation, the device then determines an actual volumetric flow rate of the fluids and actual rotation speed of the impeller.

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Cambridge, MA, United States of America

Thomas J Ober