A method of controlling sensing level in a liquid ejector is disclosed. The method includes filling a reservoir in communication with a liquid ejector with a printing material to a first level set point, receiving a drop out signal from a laser-based level sensor that reads from a surface of a melt pool in the reservoir, pausing an operation of the liquid ejector, adjusting the printing material level set point to a second level set point of printing material in reservoir that is higher than the first level set point, increasing a quantity of printing material in the reservoir to fill the reservoir to the second level set point, and resuming the operation of the liquid ejector.

A device and method of thixotropic mixing and 3D printing of alloys is provided. The method includes the steps of locating a thixotropic mixer having a discharge nozzle above a substrate; adding a molten alloy to the mixer; locating the nozzle between about 1 mm and about 20 mm from the substrate; and extruding the alloy from the nozzle onto the substrate.

Nozzles for an additive manufacturing device and methods for improving wettability of the nozzles are disclosed. The method may include subjecting the nozzle to a surface treatment. The surface treatment may include contacting a surface of the nozzle with one or more surface modifying agents. The surface modifying agents may include one or more of an oxidizing agent, an acid, a base, or combinations thereof. The one or more surface modifying agents may increase an oxygen content of the surface of the nozzle. An inner surface of the nozzle may have a water contact angle of greater than 1° and less than about 90°. The inner surface of the nozzle may be free or substantially free of a coating.

The invention relates to a print head (1) for additively manufacturing three-dimensional workpieces, comprising a housing (3), a device (28) for feeding a metal (14), a piston (5), a reservoir (7) with an outlet opening (10) and an actuator device (12) for displacing the piston (5), wherein the reservoir (7, 27) has a melt region (20) and a displacement body chamber (21) for a liquid phase (8) of the metal (14), wherein the melt region (20) adjoins the inert atmosphere (22) and is connected to the displacement body chamber (21) such that, as a result of the displacement of the piston (5), the liquid phase (8) of the metal (14) can be stimulated to pass through the outlet opening (10), said outlet opening (10) being mounted on an insert (11) of the print head (1). The invention is characterised in that the print head (1) comprises a device (50) for feeding a protective gas (60) to the outlet opening (10) of the print head (1). The invention also relates to a device (100) for additively manufacturing three-dimensional workpieces and to a method for operating a print head (1).

An array-spraying additive manufacturing apparatus and method for manufacturing a large-sized equiaxed crystal aluminum alloy ingot, comprising: a liquid aluminum spraying mechanism having array nozzles disposed in an atmospheric pressure chamber, a movable condensing mechanism disposed in the atmospheric pressure chamber below the liquid aluminum spraying mechanism, and a control mechanism. The control mechanism sends an upward guiding command to a release mechanism and issues a three-dimensional movement command to the movable condensing mechanism, such that liquid aluminum in the liquid aluminum spraying mechanism is sprayed at the surface of the movable condensing mechanism in a continuous array of liquid flows according to a preset path and is rapidly condensed to form an ingot. Also disclosed is an additive manufacturing method employing the apparatus.

A method and apparatus for manufacturing an equiaxed crystal aluminum alloy cast ingot by using additive manufacturing and rapid solidification techniques are provided. The apparatus comprises: a metal heating mechanism and a negative pressure cooling mechanism. The metal heating mechanism is located above the negative pressure cooling mechanism and is connected thereto by a nozzle. The negative pressure cooling mechanism comprises a vacuum chamber having an air inlet hole and an air outlet hole, and a three-dimensional moving ingot mechanism disposed inside the vacuum chamber. The three-dimensional moving ingot mechanism comprises a moving ingot and a two-dimensional moving platform vertically connected to the moving ingot. A water cooling mechanism is disposed outside the moving ingot, and the moving ingot is driven by a precision motor to precisely move up and down.

A manufacturing system includes a printhead, at least one profilometer, and a control system. The printhead extrudes a material onto a substrate and forms a new bead during additive manufacturing of an in-work article. The profilometer moves with the printhead and measures an in-work cross-sectional profile of existing beads of the in-work article. The control system generates in-work profile data including the in-work cross-sectional profile at a plurality of in-work profile locations, and continuously compares the in-work profile data to reference profile data of a reference article. The reference profile data includes a reference cross-sectional profile at a plurality of reference profile locations. The control system adjusts, based on the profile comparison, one or more bead forming parameters and causes the printhead to form the new bead according to the bead forming parameters to reduce or prevent nonconformities associated with forming the new bead.

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.

A method of operating a three-dimensional (3D) metal object manufacturing apparatus selects operational parameters for operation of the printer to form conductive metal traces on substrates with dimensions within appropriate tolerances and with sufficient conductive material to carry electrical currents without burning up or becoming too hot. The method identifies the material of the substrate and the bulk metal being melted for ejection and uses this identification data to select the operational parameters. Thus, the method can form conductive traces and circuits on a wide range of substrate materials including polymeric substrates, semiconductor materials, oxide layers on semiconductor materials, glass, and other crystalline materials.

A metal fused deposition printer can use the thixotropic properties of a metal (e.g., alloy) to control the viscosity of the material being deposited. The viscosity of the metal can be controlled by shearing the metal before, during, or after the deposition process. Use of the thixotropic properties can allow the viscosity of the metal to be controlled independent of the temperature of the metal. This can allow for more precise control of the temperature differential between the layer being deposited and the substrate layer, for example, such that the temperatures are substantially the same.