Abstract: 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.

Abstract: A printer fabricates an object from a computerized model using a fused filament fabrication process and a metallic build material. The Seebeck effect can be employed to monitor a temperature difference between a build material and a nozzle that is extruding the build material based on voltage. The temperature difference can, in turn, be used to control operation of the printer or to determine an absolute temperature based on direct measurement of a temperature of the nozzle.

Abstract: A control loop for extrusion of a metallic build material such as bulk metallic glass measures a force required to extrude the build material, and uses this sensed parameter to estimate a temperature of the build material. The temperature, or a difference between the estimated temperature and a target temperature, can be used to speed or slow extrusion of the build material to control heat transfer from a heating system along the feedpath. This general control loop may be modified to account for other possible conditions such as nozzle clogging or the onset of crystallization.

Abstract: 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. Nozzles associated with these devices, systems, and methods include a combination of materials suitable for withstanding prolonged exposure to high temperatures associated with certain liquid metals while facilitating efficient delivery of current to produce magnetohydrodynamic forces controllable over a range of frequencies associated with commercially viable three-dimensional fabrication.

Abstract: Devices, systems, and methods are directed to applying magnetohydrodynamic forces to liquid metal to eject liquid metal from a nozzle along a controlled pattern, such as a controlled three-dimensional pattern as part of additive manufacturing of an object. Electrodes used to deliver electric current across a firing chamber of the nozzle are formed of the same material as the liquid metal being ejected from the nozzle. For example, respective interfaces between the electrodes and the liquid metal can be molten material. Forming the electrodes and the liquid metal of the same material can facilitate, for example, ejecting liquid metals having high melt temperatures.

Abstract: 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. Nozzles associated with these devices, systems, and methods include one or more non-wetting surfaces in the vicinity of a discharge orifice of the nozzle. Such non-wetting surfaces can reduce the likelihood that wetting of the liquid metal in the vicinity of a discharge orifice of a nozzle will interfere with ejection of liquid metal droplets from the discharge orifice and, thus, can facilitate delivering droplets with accuracy suitable for commercially viable manufacturing using liquid metal to fabricate objects.

Abstract: A printer fabricates an object from a computerized model using a fused filament fabrication process and a metallic build material. A nozzle cleaning fixture may be provided for the printer that is shaped to physically dislodge solidified build material and other contaminants from the nozzle. A robotic system for the printer can be used to maneuver the nozzle into engagement with the nozzle cleaning fixture for periodic cleaning, or in response to a diagnostic condition or the like indicating a clogged nozzle.

Abstract: A class of metallic composites is described with advantageous bulk properties for additive fabrication. In particular, the composites described herein can be used in fused filament fabrication or any other extrusion or deposition-based three-dimensional printing process.

Abstract: Devices, systems, and methods are directed to switching between pneumatically actuated ejection and electrically actuated ejection of liquid metal from a nozzle moving along a controlled three-dimensional pattern to fabricate a three-dimensional object. Electrically actuated ejection can be useful, for example, for delivering discrete droplets in areas of the object requiring a high degree of accuracy. Pneumatic ejection can be useful, for example, for delivering a stream of liquid metal from the nozzle to provide liquid metal rapidly to areas of the object that require less accuracy (e.g., an inner portion of the object). Accordingly, switching between pneumatically actuated ejection and electrically actuated ejection can facilitate accurate and rapid production of parts through additive manufacturing.

Abstract: Devices, systems, and methods are directed to adjusting a pneumatic circuit associated with pneumatic ejection of liquid metal from a nozzle as the nozzle moves along a controlled three-dimensional pattern to fabricate a three-dimensional object. The adjustment of the pneumatic circuit can facilitate adjusting a pressure profile within the nozzle as pressurized gas moves through the nozzle to eject, through pneumatic force, liquid metal from the nozzle. Through adjustment of the pneumatic circuit, characteristics of the liquid metal (e.g., size, shape, and flow rate) can be controlled to facilitate control over fabrication of the three-dimensional object.

Abstract: 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. An electric current delivered to produce the magnetohydrodynamic forces can be controlled between a pulsed electric current and a direct electric current to change the rate of liquid metal ejection from a nozzle. For example, the electric current can be switched between a pulsed electric current and a direct electric current based at least in part on a position of the nozzle along the controlled pattern, providing accuracy of liquid metal deposition along portions of the pattern having more detail and providing speed of liquid metal deposition along portions of the pattern having less detail.

Abstract: A printer fabricates an object from a computerized model using a fused filament fabrication process and a build material. One or more energy directors such as ridges are formed in an exposed surface of the deposited build material to provide regions of high, localized contact force that can improve interlayer bonding between successive layers of the build material. An ultrasonic vibrator can also usefully be incorporated into the printer to apply additional energy along these energy directors during deposition of a subsequent layer.

Abstract: A printer fabricates an object from a build material based on a computerized model and a fused filament fabrication process. A nozzle for depositing the build material has an interior diameter approaching an outer diameter of build material fed to the nozzle in order to reduce extrusion and resistance forces imposed by the nozzle during deposition, while adequately constraining a planar position of the build material for accurate material deposition in a computer-controlled fabrication process.

Abstract: Devices, systems, and methods are directed to the pneumatic ejection of liquid metal from a nozzle moving along a controlled three-dimensional pattern to fabricate a three-dimensional object through additive manufacturing. The metal is movable into the nozzle as a valve is actuated to control movement of pressurized gas into the nozzle. Such movement of metal into the valve as pressurized gas is being moved into the nozzle to create an ejection force on liquid metal in the nozzle can reduce or eliminate the need to replenish a supply of the metal in the nozzle and, therefore can facilitate continuous or substantially continuous liquid metal ejection for the fabrication of parts.

Abstract: 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. The magnetohydrodynamic force can be pulsed to eject droplets of the liquid metal to provide control over accuracy of the object being fabricated. The pulsations can be applied in fluid chambers having high resonance frequencies such that droplet ejection can be effectively controlled over a wide range of frequencies, including high frequencies suitable for liquid metal ejection at rates suitable for commercially viable three-dimensional fabrication.

Abstract: Devices, systems, and methods are directed to separating sediment from liquid metal ejected, through pneumatic force, from a nozzle moving along a controlled three-dimensional pattern to fabricate a three-dimensional object. The separation of the sediment from the liquid metal can reduce the likelihood that the nozzle will become clogged or otherwise degraded during fabrication of the three-dimensional object or over the course of fabrication of multiple objects. Accordingly, the separation of the sediment from the liquid metal can facilitate, for example, the use of pneumatic ejection of liquid metal for high volume production of parts.

Abstract: 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. Magnets used to form the magnetohydrodynamic forces are thermally managed to facilitate directing strong magnetic fields into liquid metals at high temperatures. Such strong magnetic fields can be useful for imparting, under otherwise equivalent conditions, higher magnetohydrodynamic forces to liquid metal being ejected from a nozzle to form an object.

Abstract: A printer fabricates an object from a computerized model using a fused filament fabrication process. The exit of the nozzle may include a number of concentric rings, where each of which may be selectively opened or closed during extrusion to control extrusion properties such as a volume of extrudate or a mixture of material exiting the nozzle.

Abstract: A printer fabricates an object from a computerized model using a fused filament fabrication process. The shape of an extrusion nozzle may be varied during extrusion to control, e.g., an amount of build material deposited, a shape of extrudate exiting the nozzle, a feature resolution, and the like.

Abstract: A printer fabricates an object from a computerized model using a fused filament fabrication process and a bulk metallic glass. A shearing engine within a feed path for the bulk metallic glass actively induces a shearing displacement of the bulk metallic glass to mitigate crystallization, more specifically to extend processing time for handling the bulk metallic glass at elevated temperatures.