Abstract: 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.

Abstract: Disclosed is the measurement and control of height in the Z-axis of layers produced in an additive manufacturing process. The height of layers being deposited can be monitored, which may involve the use of a fiducial tower to measure a global errors or optical or other means to measure layers on a layer-by-layer basis. Droplet size, pitch and other conditions may be modified to ameliorate or correct detected errors.

Abstract: A dross removal system for magnetohydrodynamic additive. A vacuum source is used to create a pressure differential at a nozzle opening sufficient to collect dross from a pool of molten metal. The dross and any collected molten metal can be captured in a waste bin for later disposal.

Abstract: A controlled environment system for the additive manufacture of metal objects using magnetohydrodynamic jetting. A sealing plate is placed against an Péclet gap seal of a volume enclosure. A flow of inert gas is used to maintain a high-purity volume in the interior of the volume enclosure. A print head accesses the interior and delivers build material through a hole in the sealing plate. A build plate is movable relative to the sealing plate within the interior of the volume enclosure on which objects can be fabricated.

Abstract: An improved additive manufacturing system for manufacturing metal parts by magnetohydrodynamic printing liquid metal. A monitoring system including at least one camera capturing light reflected from a strobe light source. Images of the droplets are captured during their jetting and analyzed to determine whether the jetting performance is meeting specifications. A nozzle of the system has a nozzle bottom and a nozzle stem extending outward therefrom on which a meniscus of liquid metal can form. The nozzle is cleaned by bringing a ceramic rod in the vicinity of the nozzle and jetting a bead of metal which is rotated against the nozzle to remove an amount of dross.

Abstract: 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.

Abstract: A nozzle assembly for metal additive manufacturing using magnetohydrodynamic jetting. A nozzle defines a reservoir and a discharge region having a discharge orifice. A thick film heating system disposed on an exterior of the nozzle and including a first contact pad and a second contact pad connected by a heating pathway heats build material in the nozzle to a liquid state. A first electrode and a second electrode together configured to deliver an electrical current through the liquid build material in the discharge region while a magnet system delivers a magnetic field perpendicular the electrical current, thereby jetting liquid metal to form successive build layers.

Abstract: A method of developing a frequency map for an MHD jetting nozzle includes filling the MHD jetting nozzle with a liquid metal. The MHD jetting nozzle is excited with a series of jetting pulses delivered at a range of frequencies the vibration response of the MHD jetting nozzle and/or a meniscus of jetting material is measured.

Abstract: 3D printing using certain materials, such as metal containing multi-phase materials can be prone to clogs and other flow interruptions. Providing build material according to feed rate profiles having varying rates can mitigate these problems. Each feed rate profile can be broken up into blocks of time, some of which relate to fabricating the exterior geometry of the object. Each block of time can be represented by a FFT. The blocks that relate to the exterior are represented by a FFT that has significant high frequency content of 1 Hz or greater. It is beneficial to use profiles including feed rates outside of a range of feed rates suitable for steady state extrusion, being either higher or lower rates than the range limits. A combination of feed rate profiles based only on clog and flow interruption mitigation and operational to print the part according to a model can be used.

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. A feeder system can provide a continuous or substantially continuous supply of a solid metal to the nozzle to facilitate a correspondingly continuous or substantially continuous process for ejecting liquid metal as part of a commercially viable manufacturing process.

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: 3D printing using metal containing multi phase materials is prone to nozzle clogging and flow artifacts. These can be mitigated by monitoring process conditions and taking action at times based on other conditions. Forces, physical regularity, and temperatures can be monitored and service can be taken based on these, immediately, or at dynamic future points, short or longer term, such as completion of a segment or layer, or before critical geometry. Process conditions can be logged and service time can be based on functions of individual and combinations of logged data. Operating windows can be adjusted based on same. Service includes dwell time at high and low temperatures, treatment material provided into the nozzle to change the liquid composition therein. Plungers and fluid jets can expel material from nozzle inlet or outlet. Dwelling at various temperatures can liquefy clogs or cause rupture by disparate volume changes of cooling materials.

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: 3D printing using certain materials, such as metal containing multi-phase materials can be prone to clogs and other flow interruptions. Providing build material according to feed rate profiles having varying rates can mitigate these problems. Each feed rate profile can be broken up into blocks of time, some of which relate to fabricating the exterior geometry of the object. Each block of time can be represented by a FFT. The blocks that relate to the exterior are represented by a FFT that has significant high frequency content of 1 Hz or greater. It is beneficial to use profiles including feed rates outside of a range of feed rates suitable for steady state extrusion, being either higher or lower rates than the range limits. A combination of feed rate profiles based only on clog and flow interruption mitigation and operational to print the part according to a model can be used.

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: 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. A feeder system can provide a continuous or substantially continuous supply of a solid metal to the nozzle to facilitate a correspondingly continuous or substantially continuous process for ejecting liquid metal as part of a commercially viable manufacturing process.

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 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 pulsed to reduce the likelihood of formation of an oxidation layer in nozzles associated with these devices, systems, and methods. Such a reduction in the likelihood of formation of an oxidation layer in nozzles can be useful for maintaining integrity of these nozzles between periods of use, such as between formation of parts.