Metal drop ejecting three-dimensional (3D) printed object printer and method for preparing metal drop ejecting 3D object printer for printing

Abstract

To provide a metal drop ejecting three-dimensional (3D) printed object printer, and a method for preparing a metal drop ejecting 3D object printer for printing.SOLUTION: A three-dimensional (3D) metal object manufacturing apparatus is equipped with a removable vessel 104 to reduce the time required for start-up procedures after the printer is serviced. The removable vessel is filled with solid metal that is heated to its melting temperature before a bulk wire 120 is inserted into the vessel to commence printing operations. The melting of the solid metal in the removable vessel requires less time than the melting of a length of bulk wire adequate to produce a volume of melted metal suitable for printer operations. The solid metal in the removable vessel can be metal pellets, metal powder, or a solid metal insert.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] (Cross - reference to Related Applications) This disclosure cross - references U.S. Patent Application No. 17 / 147,810, entitled "A Removable Vessel And Metal Insert For Preparing A Metal Drop Ejecting Three - Dimensional (3D) Object Printer For Printing", filed on January 13, 2021, the entire content of which is incorporated herein by reference in its entirety for this co - pending continuation application.

[0002] (Field of the Invention) This disclosure relates to three - dimensional (3D) object printers that eject molten metal droplets to form objects, and more particularly, to the preparation of such printers for object printing operations.

Background Art

[0003] Three - dimensional printing, also known as additive manufacturing, is a process of creating three - dimensional solid objects from digital models of virtually any shape. Many three - dimensional printing techniques use an additive process where a layer - forming device forms successive layers of a part on top of previously deposited layers. Some of these techniques use ejection devices that discharge ultraviolet - curable materials such as photopolymers or elastomers. Printers typically operate one or more extruders to form successive layers of a plastic material that forms three - dimensional printed objects having various shapes and structures. After each layer of the three - dimensional printed object is formed, the plastic material is ultraviolet - cured, hardened, and adhered to the underlying layer of the three - dimensional printed object. This additive manufacturing method is distinguishable from conventional object - forming techniques that mostly rely on the removal of material from a workpiece by subtractive processes such as cutting or drilling.

[0004] Recently, several 3D object printers have been developed that form 3D objects by ejecting droplets of molten metal from one or more ejectors. These printers have a solid metal source, such as a roll of wire or pellets, which is fed into a heating chamber where the solid metal is melted, and the molten metal flows into the chamber of the ejector. The chamber is made of a non-conductive material around which non-insulated wires are wound. An electromagnetic field is generated when an electric current passes through a conductor, and this electromagnetic field separates the crescent shape of the molten metal at the nozzle of the chamber from the molten metal in the chamber and propels it out of the nozzle. A platform opposite the nozzle of the ejector is moved in an XY plane parallel to the plane of the platform by an actuator operated by a controller, so that the ejected metal droplets form a metal layer of an object on the platform, and another actuator, operated by the controller, changes the position of the ejector or platform in the vertical or Z direction, maintaining a constant distance between the ejector and the top layer of the formed metal object. This type of metal droplet ejector printer is also known as a magnetohydrodynamic (MHD) printer.

[0005] The extrusion unit used in MHD printers contains internal components that require periodic replacement to maintain the printer's operational state. Some components need to be replaced approximately every 8 hours. After the components have been replaced, the printer must undergo a startup process before it can be used again for manufacturing objects. Part of this startup process is the filling of the extrusion unit with molten metal. In the wire-feeding MHD printers described above, this part of the process takes time because it is necessary to supply and melt enough wire to the heating part of the extrusion unit. In some MHD printers, it may take more than 10 minutes to melt enough wire to fill the extrusion unit. Another aspect of the startup process requires about 20 minutes to perform. Thus, the entire startup process may take more than 30 minutes, with one-third of that time consumed by replenishing the extrusion unit with molten metal.

[0006] The time required to melt the wire for filling the extruder cannot be shortened simply by increasing the rate at which the wire is supplied to the heating chamber of the extruder. Increasing the supply rate causes the wire to hit the wall above the level of molten metal present in the chamber, resulting in the wire tip colliding with the heating chamber wall. Extruders are typically made of high-temperature ceramic material, which is sensitive to collisions with solid wire tips and can be damaged by this contact. It would be beneficial to be able to shorten the time it takes to fill the extruder of an MHD printer at startup without damaging the heating chamber. [Overview of the project]

[0007] A new method for operating a 3D metal object printer reduces the time required to fill the extrusion device of an MHD printer without damaging the heating chamber. The method includes placing solid metal in a removable container housing, installing the removable container in a metal droplet extrusion additive manufacturing apparatus, and operating a heater in the metal droplet extrusion additive manufacturing apparatus to a temperature that melts the solid metal in the removable container.

[0008] The new 3D metal object printer reduces the time required to fill the extruder of an MHD printer without damaging the heating chamber. The 3D metal object printer includes an extruder head having a removable container and a housing within the movable container; a heater configured to heat the removable container while the removable container is in an extruder heated to a temperature sufficient to melt solid metal within the housing of the removable container; a platform positioned opposite the extruder head; at least one actuator operably connected to at least one of the platform and the extruder head, the at least one actuator configured to move at least one of the platform and the extruder head relative to each other; and a controller operably connected to the heater, the extruder head, and the at least one actuator. The controller is configured to operate the heater to melt solid metal in the housing of the removable container, operate the extruder head to extrude droplets of molten metal toward the platform, and operate at least one actuator to move the extruder head and the platform relative to each other while the extruder head is extruding molten metal droplets toward the platform. [Brief explanation of the drawing]

[0009] The aforementioned aspects and other features of a new 3D metal object printer, which has a method for operating the 3D metal object printer and a new removable container configured for receiving metal inserts, thereby reducing the time required to fill the extruder of the MHD printer without damaging the heating chamber, will be revealed in the following description in relation to the attached drawings.

[0010] [Figure 1] This demonstrates a new 3D metal object printer that reduces the time required to fill the extrusion device of an MHD printer without damaging the heating chamber.

[0011] [Figure 2A] Figure 1 is a side view of a two-part removable container used in a 3D metal object printer, showing the metal inserts used in the removable container to reduce the time required to fill the MHD printer's extrusion device without damaging the heating chamber.

[0012] [Figure 2B] This is a side view showing the metal insert after one end of the insert has been installed in the upper housing of the removable container shown in Figure 2A.

[0013] [Figure 2C] This is a side view of an assembled, removable container, showing the installed metal inserts.

[0014] [Figure 2D] This is an end view of an assembled, removable container, showing the installed metal insert.

[0015] [Figure 2E] This is a cross-sectional view of an alternative embodiment of a single-component removable container for use with the printer shown in Figure 1.

[0016] [Figure 3] Figures 2A to 2D show side views of a metal insert for use with a two-part embodiment of a removable container.

[0017] [Figure 4] Figure 1 is a flowchart illustrating the process of filling the removable container with molten metal during the startup process of the 3D metal object printer, using the removable container and metal insert of the 3D metal object printer.

[0018] [Figure 5] This is a flowchart of the process for readjusting the removable container shown in Figure 2A.

[0019] [Figure 6A] It is a diagram of a thermal reconditioning station that can be used in the process of FIG. 5.

[0020] [Figure 6B] It is a diagram of a chemical formula reconditioning station that can be used in the process of FIG. 5.

[0021] [Figure 6C] It is a diagram of a polishing reconditioning station that can be used in the process of FIG. 5.

Mode for Carrying Out the Invention

[0022] For a general understanding of the 3D metal object printer disclosed herein, the environment for its operation, and the details of the printer and its operation, reference is made to the drawings. In the drawings, like reference numerals represent like elements.

[0023] Figure 1 shows an embodiment of a new 3D metal object printer 100 that reduces the time required to fill the extruder of an MHD printer without damaging the heating chamber of the extruder head. In the printer of Figure 1, droplets of molten bulk metal are extruded from a removable container 104 having a single nozzle 108, and the droplets from the nozzle form a swath for a layer of object on a platform 112. As used herein, the term “removable container” means a hollow container having a containment configured to hold liquid or solid material, and the container as a whole is configured to be installed and removed in a 3D metal object printer. As used herein, the term “bulk metal” means conductive metal available in aggregate form, such as wires of commonly available standard sizes or pellets of macro-size ratios. A bulk metal source 116, such as a metal wire 120, is supplied to a wire guide 124 extending through an upper housing 122 within the dispensing head 140, melted in a removable container 104, and provided with molten metal to be extruded from a nozzle 108 through an orifice 110 in the base plate 114 of the dispensing head 140. As used herein, the term “nozzle” means an orifice in the removable container configured for the extrusion of molten metal droplets from the containment within the removable container. As used herein, the term “dispensing head” means the housing and components of a 3D metal object printer that melts, extrudes, and adjusts the extrusion of molten metal droplets for the manufacture of a metal object. The volume level of molten metal in the removable container 104 is maintained at the upper level 118 of the removable container. The removable container 104 slides into the heater 160, the inner diameter of which contacts the removable container, allowing the solid metal in the containment of the removable container to be heated to a temperature sufficient to melt the solid metal. As used in this document, the term “solid metal” means a metal as defined in the periodic table of elements, or an alloy formed by these metals in a solid form rather than a liquid or gaseous state. The heater is separated from the removable container to form a volume between the heater and the removable container 104.The inert gas supply unit 128 provides a pressure-regulated source of an inert gas, such as argon, to the discharge head through the gas supply pipe 132. The gas flows through the volume between the heater and the removable container and exits through the orifice 110 in the discharge head and base plate 114 around the nozzle 108. This flow of inert gas close to the nozzle insulates the discharged droplets of molten metal from the surrounding air on the base plate 114, preventing the formation of metal oxides during the flight of the discharged droplets.

[0024] The dispensing head 140 is mounted to move within a z-axis trajectory to accommodate the vertical movement of the dispensing head relative to the platform 112. One or more actuators 144 are operably connected to the dispensing head 140 to move the dispensing head along the Z-axis and to the platform 112 to move the platform in the XY plane below the dispensing head 140. The actuators 144 are operated by a controller 148 to maintain an appropriate distance between the orifice 110 in the base plate 114 of the dispensing head 140 and the uppermost surface of an object on the platform 112.

[0025] As droplets of molten metal are ejected toward the platform 112, moving the platform 112 in the XY plane creates swaths of molten metal droplets on the object being formed. The controller 148 also operates the actuator 144 to adjust the vertical distance between the ejector head 140 and the most recently formed layer on the substrate, facilitating the formation of other structures on the object. The molten metal 3D object printer 100 is shown in Figure 1 as operating vertically, but other alternative orientations may be used. Also, the embodiment shown in Figure 1 has a platform that moves in the XY plane and the ejector head that moves along the Z axis, but other arrangements are possible. For example, the actuator 144 may be configured to move the ejector head 140 in the XY plane and along the Z axis, or it may be configured to move the platform 112 in both the XY plane and along the Z axis.

[0026] The controller 148 may be implemented using one or more general-purpose or dedicated programmable processors to execute programmed instructions. Instructions and data required to perform programmed functions may be stored in memory associated with the processor or controller. The processors, their memories, and interface circuits constitute the controller to perform the operations described above and below. These components may be provided on a printed circuit card or as circuits in an application-specific integrated circuit (ASIC). Each circuit may be implemented on a separate processor, or multiple circuits may be implemented on the same processor. Alternatively, the circuits may be implemented as individual components or circuits provided in a very large-scale integrated (VLSI). Furthermore, the circuits described herein may be implemented in combination of processors, ASICs, individual components, or VLSI circuits. During the formation of a metal object, image data of the structure to be manufactured is transmitted to the processor(s) of the controller 148, either from the scanning system or via an online or workstation connection, to process and generate signals that operate the components of the printer 100 to form the object on the platform 112.

[0027] Among these components is a switch 152. One switch 152 may be selectively operated to supply power to the heater 160 from a power source 156, and another switch 152 may be operated to supply power to the coil 164 from another power source 156 to generate an electric field for ejecting droplets from the nozzle 108. Because the heater 160 generates a large amount of heat at a high temperature, the coil 164 is located within a chamber 168 formed by one (circular) or two or more walls (linear) of the ejector head 140. As used in this document, the term “chamber” means a volume contained within one or more walls in which the heater, coil, and removable container of the 3D metal object printer are located. The removable container 104 and the heater 160 are located within this chamber. The chamber is fluidically connected to a fluid source 172 via a pump 176 and is also fluidly connected to a heat exchanger 180. As used in this document, the term “fluid source” refers to a container of liquid having properties useful for absorbing heat. The heat exchanger 180 is connected via a return to the fluid source 172. Fluid from the source 172 flows through the chamber, absorbing heat from the coil 164, and the fluid carries the absorbed heat through the exchanger 180, where the heat is removed by known means. The cooled fluid is returned to the fluid source 172 for further use in maintaining the coil temperature within a suitable operating range.

[0028] The controller 148 of the 3D metal object printer 100 requires data from an external source to control the printer for the manufacture of metal objects. Generally, a three-dimensional model or other digital data model of the object to be formed is stored in memory operably connected to the controller 148, and the controller may be able to access a remote database where the digital data model is stored via a server or the like, or a computer-readable medium where the digital data model is stored may be selectively connected to the controller 148 and become accessible. This three-dimensional model or other digital data model is processed by a slicer implemented with the controller to generate machine-ready instructions that the controller 148 executes in a known manner, thereby operating the components of the printer 100 and forming a metal object corresponding to that model. The generation of machine-ready instructions may include the creation of an intermediate model, such as when a CAD model of a device is converted to an STL data model, or to another polygonal mesh or other intermediate representation, and this intermediate model may then be processed to generate machine instructions, such as g-code, for the printer to manufacture the device. When used in this document, the term “machine-responsive instruction” refers to computer language commands executed by a computer, microprocessor, or controller to operate the components of a 3D metal object additive manufacturing system to form a metal object on the platform 112. The controller 148 executes machine-responsive instructions to control the ejection of molten metal droplets from the nozzle 108, the positioning of the platform 112, and the maintenance of the distance between the orifice 110 and the uppermost layer of the object on the platform 112.

[0029] Figure 2A is a side view of the removable container 104 of the printer 100. This embodiment of the removable container 104 is a two-part structure including an upper housing 204 and a lower housing 208. As used herein, the term “housing” means a structure that has a portion of a housing inside it and is configured to be fixed to another structure to form a removable container. The lower housing 208 contains a nozzle 108 (shown in Figure 1). The upper housing 204 includes a collar 228 that is longer than the lower housing 208 and has a circumference equal to the outer circumference of the lower housing 208. An opening in the lower housing 208 opposite the nozzle inside the lower housing 208 has a flange that extends from the opening and has a circumference smaller than the inner circumference of the collar 228. The collar 228 has an inner step that is recessed from the end of the upper housing 204 fixed to the lower housing 208 by a distance corresponding to the distance the flange of the lower housing extends from the lower housing. Therefore, the flange of the lower housing slides within the collar 228 until it contacts the inner step of the upper housing 204 so as to fit within the inner circumference of the collar 228. When the upper housing 204 and the lower housing 208 are assembled, they form a housing having a shape corresponding to the metal insert 212. The metal insert 212 is a solid metal piece having an elongated, rounded stem portion 216 and a bulbous portion 220 terminating at a pointed end that fits into the nozzle 108. As used in this text, the term “elongated” means a structure longer than its width, and the term “rounded” means a structure having at least a partially cylindrical shape. As used in this text, the term “bulbous” means a structure having a conical shape along at least a portion of its longitudinal axis. The upper housing 204 is also formed together with the guide flange 224. This flange fits into a groove within the dispensing head 140 to correctly orient the removable container 104 within the printer 100 and to hold the container in its correct orientation after it has been placed within the dispensing head 140.

[0030] The upper housing 204 is formed of boron nitride, and the lower housing 208 is formed of graphite. Both of these materials are high-temperature ceramics. In one embodiment, the upper and lower housings are heated to a temperature in the range of about 800°C to about 850°C over a period of 8 hours or more. The containment within the removable container 104 may be coated with a suitable antioxidant flame retardant material that helps to reduce the formation of oxides on the metal insert. As used herein, the term “antioxidant flame retardant” means any material that reduces the formation of metal oxides in the type of metal placed in the containment of the removable container. Since the boron nitride forming the upper housing is not conductive, it does not hinder the generation of an electric field used to eject molten metal droplets from the containment through the nozzle 108 and orifice 110. The overall dimensions of the assembled removable container are 55 mm, with the upper housing being 40 mm long and the lower housing being 15 mm long. In the Color 228, the circumference of the upper housing is approximately 50 mm and the diameter is approximately 16 mm, while the circumference of the widest part of the lower housing is approximately 50 mm and the diameter is approximately 16 mm.

[0031] Before being installed in the ejector head 140 of the printer 100, the metal insert 212 is loaded into a removable container 104. This is done by pressing the stem portion 216 of the insert 212 into the housing portion of the upper housing 204 (Figure 2B) or by pressing the tip of the bulb portion 220 into the lower housing. Sometimes several spots of cyanoacrylate adhesive, more commonly known as "super glue," are applied to either the inner step of the lower housing 208 or the inner circumference of the collar 228, and the inner step of the lower housing 208 is then slid within the inner circumference of the collar 228 to fix the lower and upper housings together, as shown in Figure 2C. This adhesive is removed by the heat applied from the heater 160 during printer operation, so that the two housings can be separated for printer maintenance. As shown in Figure 2D, the stem portion 216 is visible through the opening in the upper housing. This opening is located opposite the wire guide 124 to receive the wire 120 after the metal insert 212 has melted in the removable container 104. An inert gas source 128 is connected to the upper housing and supplies an inert gas (insert gas) to the containment in the removable container so that the environment inside the removable container does not oxidize the molten metal in the containment of the container. A thermocouple (not shown) is placed in the opening 232 to provide a signal indicating the heat inside the removable container so that the controller can adjust the operation of the heater 160.

[0032] Figure 2E is a cross-sectional view of an alternative embodiment of the removable container. This container 104 is a single-piece structure; that is, the container has a single housing having a nozzle at one end and an open end at the other. To fill this embodiment, the metal insert 216 is composed of pelletized solid metal or solid metal powder and is poured through an opening that receives a wire. Similarly, the embodiments of the removable container 104 shown in Figures 2A to 2D can be assembled first, and then pelletized solid metal or solid metal powder can be poured through an opening in the upper housing to fill the container. The guide flange 224 slides in a mounting groove in the ejector head 140 to orient the removable container during installation and to maintain its orientation within the printer.

[0033] As described above in relation to Figures 2A to 2D, the metal insert 212 is a solid metal piece having an elongated, rounded stem-like portion 216 and a bulb-like portion 220 terminating at a pointed end that fits into the nozzle 108. After being manufactured, the metal insert is stored in a container 222 as shown in Figure 3. The container 222 is sealed with a lid 226 having a self-sealing hole connected to a vacuum section 230, so that air can be removed from the container before transport. Removing air helps prevent the formation of oxides on the solid metal. When the conduit connecting the vacuum section to the inside of the container 22 is removed, the self-sealing hole closes and the vacuum inside the container is maintained. The metal insert 212 is sized to slide easily into the housing formed by the upper and lower housings. Therefore, in the above-described embodiment, the length of the stem portion 216 from the joint with the bulbous portion 220 to the end of the stem portion is 32 mm, and the circumference of the stem portion is 8.5 mm, which narrows slightly towards its end, so that the stem portion fits easily into the horizontal cross-sectional area of ​​the housing in the upper housing. The circumference of the bulbous portion near the joint with the stem portion 216 is approximately 37.7 mm, the diameter is approximately 12 mm, and the length of the bulbous portion from the joint with the stem portion to the tip is 19 mm. In some embodiments, the metal insert is coated with various coating agents to prevent oxidation, such as lithotriptyline. The metal insert is made of a solid metal such as bulk aluminum or other known metals that may be used in metal droplet ejection printers.

[0034] Figure 4 shows the process for operating a material deposition 3D object printer to reduce the time required to prepare a removable container for printing operations. In the description of the process, when the process performs several tasks or functions, it means that the controller or general-purpose processor executes program instructions stored in a non-temporary computer-readable storage medium operably connected to the controller or processor in order to perform a task or function by working with data or by manipulating one or more components in the printer. The controller 148 described above may be such a controller or processor. Alternatively, the controller may be implemented with two or more processors and associated circuits and components, each configured to form one or more tasks or functions described herein. In addition, the steps of the method may be performed in any executable chronological order, regardless of the order shown in the figure or the order in which the processes are described.

[0035] Figure 4 is a flowchart of process 400 of filling a removable container with molten metal during the startup process of the 3D metal object printer, using a removable container and metal insert in the 3D metal object printer of Figure 1. This process begins with the removal of the removable container 104 from the 3D metal object printer, which has been taken offline and made available for cooling (block 404). The removable container is then filled with solid metal. When the removable container is a single-piece structure embodiment (block 408), the container is filled by pouring solid metal pellets or solid metal powder through an opening at the end of the container into which a bulk wire is later inserted (block 412). In a two-part embodiment of the removable container, the container is separated into its two parts (block 416), and the metal insert is removed from its container to prevent oxide formation (block 420). The elongated, rounded end of the metal insert is positioned in the upper housing of the container (block 424), and then the bulbous end is inserted into the lower housing (block 428). Next, the upper and lower housings are fixed to each other (block 432). Alternatively, in a two-part embodiment, metal powder or metal pellets may be filled while the housings remain fixed to each other. Once the removable container is filled with solid metal, the removable container is placed in a heater within the 3D metal object printer (block 436), and the printer is closed (block 440). The heater is operated to a temperature at which the removable container melts the solid metal, filling the container with molten metal (block 444), and bulk metal wire may be inserted into the wire guide so that the ends of the wire from the wire feed unit are positioned in the molten metal in the removable container (block 448). The printer may then resume operation for manufacturing a metal object (block 452).

[0036] Occasionally, when the container is removed from the printer, it needs to be readjusted. When used in this document, readjusting a two-part removable container means that the lower housing is replaced and the upper housing is wiped with a cleaning solvent to remove hardened aluminum from the chamber within the upper housing. A method for readjusting a single-part removable container is shown in Figure 5. Process 500 begins with the container or at least the lower housing being placed in one of the readjustment stations shown in Figure 6A, Figure 6B, or Figure 6C (block 504). The readjustment station is then operated to remove solidified metal droplets from the outer surface of the nozzle (block 508). Once the removal is complete, the container is removed (block 512), filled with solid metal as described above (block 516), and then stored in a container such as container 222 that prevents oxide formation on the metal insert (block 520).

[0037] The adjustment station 604 shown in Figure 6A removes solid metal droplets by heat-treating the nozzle of a removable container. In this station, a heater 608 is activated to heat the outside of the nozzle 610 to a temperature sufficient to melt the solid metal droplets. After the droplets have melted, an actuator 612 is activated to rotate the platform 614 on which the container is fixed at a speed that generates centrifugal force to cast the molten metal droplets. The adjustment station 620 shown in Figure 6B removes solid metal droplets by chemically treating the nozzle of a removable container. In this station, an applicator such as a sprayer 624 applies one or more chemicals to the outer surface of the nozzle to etch or otherwise erode the solid metal droplets from the nozzle. The adjustment station 630 shown in Figure 6C removes solid metal droplets by mechanically treating the nozzle of a removable container. In this station, an actuator 634 is operated to press an abrasive tool such as a spin polishing wheel 638 against the outer surface of the nozzle to crush or otherwise polish the solid metal droplets from the nozzle.

[0038] It will be understood that variations or substitutions of the features and functions disclosed above and other features and functions may, preferably, be combined into many other different systems, applications, or methods. Various currently unforeseen or unexpected substitutions, modifications, variations, or improvements, which are also intended to be covered by the following claims, may subsequently be made by those skilled in the art.

Claims

1. A metal droplet ejection device, comprising: a dispenser head having a removable container and a receiving portion within the removable container; a heater configured to heat the removable container to a temperature sufficient to melt a solid metal within the receiving portion of the removable container while the removable container is within the dispenser head; a platform positioned opposite the ejector head; at least one actuator operatively connected to at least one of the platform and the ejector head, the at least one actuator configured to move the at least one of the platform and the ejector head relative to one another; and a controller operatively connected to the heater, the ejector head, and the at least one actuator, the controller comprising: operating the heater to melt a solid metal within the receiving portion of the removable container; operating the dispenser head to dispense droplets of molten metal toward the platform; a controller configured to operate the at least one actuator to move the ejector head and the platform relative to one another while the ejector head ejects molten metal droplets toward the platform.

2. the heater is configured to define a volume between the heater and the removable container; 2. The metal drop ejection apparatus of claim 1, wherein a gas supply is operably connected to the volume between the heater and the removable container such that gas from the gas supply flows through the volume and via a nozzle in the removable container to insulate the molten metal droplets from ambient air while the molten metal droplets are in the air toward the platform.

3. a coil of wire configured adjacent to and exterior to the heater; A current source; a switch operably connected between the coil of wire and the current source; 3. The metal drop ejection device of claim 2, further comprising: the controller further configured to operate the switch to selectively connect the coil of wire to the current source to eject droplets from the nozzle of the removable container.

4. The ejection device head includes: at least one wall surrounding a chamber configured to form a volume around the coil of wire, the heater, and the removable container, the at least one wall having a first port for receiving a fluid and a second port for exiting the fluid; A supply of fluid; a pump operatively connected between the fluid supply and the first port of the at least one wall, the pump configured to move the fluid from the fluid supply to the first port such that the fluid moves through the chamber before exiting the chamber through the second port; 4. The metal drop ejection device of claim 3, further comprising: a heat exchanger operably connected to the second port, the heat exchanger receiving the fluid from the chamber in response to the pump moving fluid to the first port, the heat exchanger configured to remove heat from the fluid passing through the second port.

5. 5. The metal drop ejection device of claim 4, wherein the heat exchanger is operatively connected to a supply of the fluid for returning the fluid to the supply of the fluid after the heat has been removed from the fluid by the heat exchanger.

6. The removable container comprises: A first housing; and a second housing, the first housing and the second housing being configured for separation and securability to one another to selectively form the removable container.

7. The first housing includes:

7. The metal drop ejection device of claim 6, further comprising a first opening at an end of the first housing opposite an end of the first housing configured to be secured together with the second housing to form the removable container, the first opening configured to receive a bulk metal wire from a supply of bulk metal wire and direct the bulk metal wire into the receiving portion of the removable container.

8. 8. The metal drop ejection device of claim 7, wherein the second housing includes a nozzle at an end of the second housing opposite another end of the second housing configured to be secured to the first housing.

9. 9. The metal drop ejection device of claim 8, wherein the containment portion within the removable container is elongated and rounded within the first housing and bulbous within the second housing.

10. 10. The metal drop ejection device of claim 9, wherein the bulbous shaped portion of the receptacle in the second housing is shorter in length than the elongated, rounded shaped portion of the receptacle in the first housing.

11. 11. The metal drop ejection device of claim 10, wherein the narrowest portion of the bulbous portion of the receptacle in the second housing is adjacent the nozzle in the second housing.

12. The metal drop ejection device of claim 11 , wherein the first housing and the second housing are formed from a high temperature ceramic material.

13. 13. The metal drop ejection device of claim 12, wherein the first housing is formed of a first high temperature ceramic material and the second housing is formed of a second high temperature ceramic material different from the first high temperature material.

14. 14. The metal drop ejection device of claim 13, wherein the first high temperature ceramic material is boron nitride and the second high temperature ceramic material is graphite.

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