Devices, systems, and methods are directed to applying magnetohydrodynamic forces to liquid metal to eject liquid metal along a controlled pattern, such as a controlled three-dimensional pattern as part of additive manufacturing of an object. Electric current delivered to a meniscus of the liquid metal in a quiescent state can be directed to exert a pullback force on the liquid metal. The pullback force can be sufficient to draw the liquid metal, in the quiescent state, in a direction toward the nozzle to reduce the likelihood of unintended wetting of surfaces of the nozzle between uses of the nozzle.

In a method and system for laser induced forward transfer (LIFT), energy (E1,E2) is deposited according to a non-Gaussian intensity profile (Ixy) which is spatially tuned across an interface (11xy) of the donor material (11m) to cause the donor material (11m) to be ejected from the donor substrate as an extended jet (Je) momentarily bridging the transfer distance (Zt) between the donor substrate (11) and the acceptor substrate (12) during a transfer period (Tt). A locally increased intensity spike (Is) at a center of the intensity profile (Ixy) causes a relatively thick jet (J1) of donor material to branch into a relatively thin jet (J2) at a branching position (J12) between the donor substrate (11) and acceptor substrate (12). The thick jet (J1) allows a relatively large transfer (Zt) distance while the thin jet (J2) deposits a relatively small droplet (Jd) of donor material (11m).

A method of additive manufacturing using magnetohydrodynamic (MHD) printing of liquid metal. A first current pulse is applied to a liquid metal in a nozzle to eject a droplet from a discharge orifice. A second current pulse is applied to the liquid metal in the nozzle to reduce an amplitude of the oscillations in a meniscus on the discharge orifice. The second current pulse can be either of an opposite or the same polarity as the first current pulse and is timed according to according to the oscillation.

One example provides a fluidic die including a semiconductor substrate, and a nozzle layer disposed on the substrate, the nozzle layer having a top surface opposite the substrate and including a nozzle formed therein, the nozzle including a fluid chamber disposed below the top surface and a nozzle orifice extending through the nozzle layer from the top surface to the fluid chamber, the fluid chamber to hold fluid, and the nozzle to eject fluid drops from the fluid chamber via the nozzle orifice. An electrode is disposed in contact with the nozzle layer about a perimeter of the nozzle orifice, the electrode to carry an electrical charge to adjust movement of electrically charged components of the fluid.

Systems and methods for additive manufacturing, and, in particular, such methods and apparatus as employ pulsed lasers or other heating arrangements to create metal droplets from donor metal micro wires, which droplets, when solidified in the aggregate, form 3D structures. A supply of metal micro wire is arranged so as to be fed towards a nozzle area by a piezo translator. Near the nozzle, an end portion of the metal micro wire is heated (e.g., by a laser pulse or an electric heater element), thereby causing the end portion of the metal micro wire near the nozzle area to form a droplet of metal. A receiving substrate is positioned to receive the droplet of metal jetted from the nozzle area.

A method for operating a printer can include draining a print material from a printer, placing a sacrificial metal into the printer, ejecting the sacrificial metal from a nozzle of the printer, and cooling to printer to a temperature that is below a melting point of the print material and the sacrificial metal. The print material can be or include aluminum and the sacrificial metal can be or include tin. The print material can be drained from the printer when the print material is in molten form, for example, from about 600° C. to about 2000° C. The sacrificial metal can be ejected from the nozzle at a temperature above the melting point of the sacrificial metal but below the melting point of the print material, for example, below about 300° C. The method can reduce or eliminate cracking of various printer structures such as the nozzle during a shutdown or cooling of the printer.

A jetting assembly that can be used to print a high-temperature print material such as a metal or metal alloy, an aqueous ink, or another material, includes an actuator for heating a gas such as a non-volatile gas within a gas cavity. The actuator rapidly heats the gas within the gas cavity, which rapidly increases a volume of the gas, thereby applying a pressure to the print material within an expansion channel that is in fluid communication with the gas cavity. In turn, the print material within the expansion channel applies a pressure to the print material within a nozzle bore, which forces a drop of the print material from a nozzle. The jetting assembly further includes a supply inlet that supplies the print material to the expansion chamber and the nozzle bore, for example, from a reservoir.

Devices, systems, and methods are directed to applying magnetohydrodynamic forces to liquid metal to eject liquid metal along a controlled pattern, such as a controlled three-dimensional pattern as part of additive manufacturing of an object. Electric current delivered to a meniscus of the liquid metal in a quiescent state can be directed to exert a pullback force on the liquid metal. The pullback force can be sufficient to draw the liquid metal, in the quiescent state, in a direction toward the nozzle to reduce the likelihood of unintended wetting of surfaces of the nozzle between uses of the nozzle.

The electrohydrodynamic print head includes a nozzle layer with a plurality of nozzles A feed layer is arranged above nozzle layer. It contains feed ducts for feeding ink to the nozzles as well as electrically conducting feed lines for feeding voltages to electrodes at nozzles. The feed layer includes one or more dielectric sublayers, which is/are structured to form the feed ducts and feed lines. Some of the sublayers contain vertical via sections and others contain horizontal interconnect sections. The feed layer is structured for customizing the print head easily.

The present disclosure relates to an induced electrohydrodynamic jet printing apparatus including an induced auxiliary electrode, and the induced electrohydrodynamic jet printing apparatus including an induced auxiliary electrode according to the present disclosure includes a nozzle for discharging supplied solution towards an opposite substrate through a nozzle hole formed at one end; a main electrode coated with an insulator and interpolated inside the nozzle, thus not contacting the solution inside the nozzle but separated from the solution; the induced auxiliary electrode made of a conductive material and formed at an outer surface of the nozzle; and a voltage supply for applying voltage to the main electrode.