An inductive hot-end for a 3d-printer to melt and dispense metal

Abstract

A dispensing head for a 3D printing system includes an outer tube, a nozzle, an inner tube, and a conductive wire. The outer tube extends from a first end to a second end along a central longitudinal axis and defines a central channel. The nozzle is disposed at least partially within the central channel and defines a nozzle channel and includes a ferromagnetic material. The inner tube disposed is at least partially within the nozzle channel and defines a dispensing channel configured to expel a filament material. The conductive wire is wound around the outer tube to define an inductive coil. An electromagnetic field produced by the inductive coil and a power source coupled thereto heats the nozzle. Heat is transferred from the nozzle to the filament material within the dispensing channel to melt and expel the filament material from the dispensing opening of the inner tube.

Description

AN INDUCTIVE HOT-END FOR A 3D-PRINTER TO MELT ANDDISPENSE METALCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This applications claims priority to, and the benefit of, U.S. Provisional Patent Application No. 63 / 675,399 filed July 25, 2024, the entire contents of which are hereby incorporated by reference.BACKGROUND

[0002] 3D printers are complex, belt-driven machines that create three-dimensional models by printing them layer-by-layer. Fused Deposition Modeling (FDM) printers use a heated spool of plastic filament to physically draw each layer line-by-line. FDM printers often include a a dispensing head that heats and dispenses the plastic filament onto a base plate. However, FDM printers are limited to plastic material applications. Another type of 3D printing, Direct Metal Laser Sintering (DMLS), uses precise lasers to melt fine metal powder layer-by-layer. Although DMLS allows for the use of metal materials, rather than plastic, the associated costs and the required power are both high.

[0003] Therefore, a need exists for 3D printing devices and systems capable of metal printing that lower the cost and increase the accessibility to the technology.SUMMARY

[0004] One implementation of the present disclosure is a dispensing head. The dispensing head includes an outer tube, a nozzle, an inner tube, and a conductive wire. The outer tube extends from a first end to a second end along a central longitudinal axis. The outer tube defines a central channel. The nozzle is disposed at least partially within the central channel and defines a nozzle channel aligned along the central longitudinal axis. The nozzle includes a ferromagnetic material. The inner tube is disposed at least partially within the nozzle channel and defines a dispensing channel aligned along the central longitudinal axis. The inner tube has a distal end defining a dispensing opening configured to expel a filament material disposed within the dispensing channel. The conductive wire is wound to define an inductive coil defining an inductive channel therein. At least a portion of the outer tube, the nozzle, and the inner tube are disposed within the inductive channel. The conductive wire is coupled to a power source. Theinductive coil is configured to produce an electromagnetic field within the inductive channel that heats the nozzle. Heat is transferred from the nozzle to the filament material within the dispensing channel of the inner tube to melt the filament material expelled from the dispensing opening of the inner tube.

[0005] In some implementations, the outer tube includes ceramic.

[0006] In some implementations, the inner tube includes graphite.

[0007] In some implementations, the nozzle includes steel.

[0008] In some implementations, the conductive wire is wound around an outer surface of the outer tube to define the inductive coil.

[0009] In some implementations, heat transfer from the nozzle to the filament material within the dispensing channel is facilitated by the inner tube including a thermally conductive material.

[0010] In some implementations, the dispensing head further includes a heat sink coupled to a hot end of the dispensing head that includes the outer tube, the nozzle, and the inner tube.

[0011] In some implementations, the heat sink is coupled to the hot end of the dispensing head via a heat brake disposed therebetween.

[0012] In some implementations, the heat sink is coupled to (i) the first end of the outer tube (ii) a first end of the nozzle, (iii) and / or a proximal end of the inner tube.

[0013] In some implementations, the dispensing head further includes a feeding tube extending through a channel defined through the heat sink, the feeding tube configured to accept and guide the filament material toward the hot end of the dispensing head.

[0014] In some implementations, the power source is an induction coil power source.

[0015] In some implementations, the filament material is an aluminum alloy.

[0016] In some implementations, the filament material is fed into the first end of the outer tube and through each of the central channel, the nozzle channel, and the dispensing channel, wherein the filament material within the dispensing channel is heated at least to a melting temperature such that liquid filament material is dispensed from the dispensing opening of the inner tube.

[0017] In some implementations, the dispensing head further includes a housing covering a substantial portion of the dispensing head but exposing at least the distal end of the inner tube.

[0018] In some implementations, the dispensing head is attachable to a gantry of a controllably moveable device (e.g., existing 3D printer).

[0019] Another implementation of the present disclosure is a dispensing system including a 3D printing device and a dispensing head. The 3D printing device includes a gantry and a base plate. The dispensing head is coupled to the gantry. The dispensing head includes an outer tube, a nozzle, an inner tube, and a conductive wire. The outer tube extends from a first end to a second end along a central longitudinal axis. The outer tube defines a central channel. The nozzle is disposed at least partially within the central channel and defines a nozzle channel aligned along the central longitudinal axis. The nozzle includes a ferromagnetic material. The inner tube is disposed at least partially within the nozzle channel and defines a dispensing channel aligned along the central longitudinal axis. The inner tube has a distal end defining a dispensing opening configured to expel a filament material disposed within the dispensing channel. The conductive wire is wound to define an inductive coil defining an inductive channel therein. At least a portion of the outer tube, the nozzle, and the inner tube are disposed within the inductive channel. The conductive wire is coupled to a power source. The inductive coil is configured to produce an electromagnetic field within the inductive channel that heats the nozzle. Heat is transferred from the nozzle to the filament material within the dispensing channel of the inner tube to melt the filament material expelled from the dispensing opening of the inner tube.

[0020] In some implementations, the melted filament material expelled from the dispensing opening of the inner tube is deposited on the base plate of the 3D printing device.

[0021] In some implementations, the dispensing head is moveable along the gantry in at least one direction relative to the base plate.

[0022] In some implementations, the dispensing system further includes a controller configured to actuate the gantry to move the dispensing head in at least one direction with respect to the base plate.

[0023] In some implementations, the dispensing system further includes a spool of the filament material, wherein the filament material is fed through the dispensing channel of the dispensing head.

[0024] Another implementation of the present disclosure is a method of dispensing a filament material. The method includes providing a dispensing head. The dispensing head includes anouter tube extending from a first end to a second end along a central longitudinal axis, the outer tube defining a central channel. The dispensing head further includes a nozzle disposed at least partially within the central channel and defining a nozzle channel aligned along the central longitudinal axis, the nozzle including a ferromagnetic material. The dispensing head further includes an inner tube disposed at least partially within the nozzle channel and defining a dispensing channel aligned along the central longitudinal axis, the inner tube having a distal end defining a dispensing opening. The dispensing head further includes a conductive wire wound to define an inductive coil defining an inductive channel therein, wherein at least a portion of the outer tube, the nozzle, and the inner tube are disposed within the inductive channel. The conductive wire is coupled to a power source. The method further includes producing an electromagnetic field within the inductive channel via delivery of energy from the power source to the inductive coil. The resulting electromagnetic field heats the nozzle of the dispensing head. The method further includes feeding the filament material into the dispensing channel of the dispensing head. The method further includes melting the filament material within the dispensing channel via heat transfer from the nozzle to the filament material. The method further includes expelling the melted filament material from the dispensing opening of the inner tube.

[0025] In some implementations, the filament material is a metal alloy.

[0026] In some implementations, the method further includes coupling the dispensing head to a 3D printing device and controllably moving the dispensing head along a portion of the 3D printing device relative to a base plate thereof to produce a 3D printed product from the melted filament material.

[0027] The device is explained in even greater detail in the following drawings. The drawings are merely exemplary and certain features may be used singularly or in combination with other features. The drawings are not necessarily drawn to scale.

[0028] Additional advantages will be set forth in part in the description which follows or may be learned by practice. The advantages will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive, as claimed.BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIGS. 1 A-1D show images of a 3D printing system configured with a metal -dispensing head, according to one implementation.

[0030] FIG. IE shows a top down view of the dispensing portion of the dispensing head, according to one implementation.

[0031] FIG. 2A shows a side view and a cross-sectional view of the dispensing portion of the dispensing head, according to one implementation.

[0032] FIG. 2B shows an exploded view of the dispensing head of FIG. 2A.

[0033] FIG. 2C shows a nozzle and other elements of the dispensing portion of the dispensing head, according to one implementation.

[0034] FIG. 2D shows an image of an example ceramic tube having a nozzle therein, according to one implementation.

[0035] FIG. 3 A shows a detail view of a dispensing head, according to another implementation.

[0036] FIG. 3B shows an image of an exemplary dispensing head, according to one implementation.

[0037] FIG. 3C shows an image of a 3D printing system configured with a metal -dispensing head, according to one implementation.

[0038] FIG. 4A shows various views of a graphite inserts for the dispensing head, according to one implementations.

[0039] FIG. 4B shows various views of a heat brake connector, according to various implementations.

[0040] FIGS. 5A-5D show images of a metal material being dispensed from a dispensing head, according to an experimental implementation.

[0041] FIGS. 5E-5F show images of metal material dispensed from a dispensing head, according to an experimental implementation.

[0042] FIG. 6A shows a diagram of a cooling system compatible with a dispensing head, according to one implementation.

[0043] FIG. 6B shows a diagram of a gas-implemented dispensing head, according to one implementation.

[0044] Various objects, aspects, features, and advantages of the disclosure will become more apparent and better understood by referring to the detailed description taken in conjunction with the accompanying drawings, in which like reference characters identify corresponding elements throughout. In the drawings, like reference numbers generally indicate identical, functionally similar, and / or structurally similar elements.DETAILED DESCRIPTION

[0045] Referring generally to the figures, an induction hot-end for a 3D printer (e.g., a dispensing head) to melt and dispense metal material is shown, according to various implementations.

[0046] The disclosed hot end or dispensing head may replace existing hot ends, dispensing heads, and / or nozzle systems for 3D printers (e.g., Acrylonitrile Butadiene Styrene (ABS) plastic dispensing systems on commercial 3D printers). The disclosed dispensing head is configured to heat, melt, and dispense metal material (e.g., from a metal wire) in a manner similar to that of existing 3D printers. For example, just as in a 3D printer using ABS, the disclosed dispensing head melts and dispenses material onto the base plate in a preconfigured and controlled manner (e.g., following instructions from the controller). Each layer of melted metal solidifies on the base plate, and a printed structure is formed in layers.

[0047] One advantage of the disclosed system, device, and method of the induction-based hot end is that users can affordably 3D print objects comprising metal material at home (or in other settings) while being energy efficient. In some implementations, a 12-volt induction heater is provided, and the hot end can run for long periods of time while maintaining a low operational cost and high temperature. Additionally, the size of the hot end allows it to be mounted to consumer-grade 3D printers (e.g., existing 3D printers). In some examples, a custom mounting bracket or mounting system is provided with the disclosed dispensing head. The induction-based hot end operates with consumer 3D printers by detaching the factory hot end and replacing it with the induction hot end herein disclosed. Leaving the wires to the factory hot end connected, offsetting the factory extruder, and feeding the stock PTFE tube to the new hot end allows material to be fed without a firmware update or other substantial changes to the operation of the3D printer. The power may be supplied separately to the hot end to ensure the proper power output.

[0048] In some examples, the hot end dispensing head operates by using an induction coil to heat a steel nozzle or insert. The induction coil creates an oscillating electromagnetic field that causes ferrous metals to heat up. In some examples, the steel nozzle is placed inside of a ceramic tube that sits inside of the induction coil. A small graphite tube may be placed inside of the steel tube. The graphite tube may facilitate dispensing of the metal by, for example, preventing molten metal from welding to the steel nozzle.Example Device and System

[0049] FIGS. 1 A-1E show a dispensing system 10 according to one implementation of the disclosure. The dispensing system 10 is configured as a 3D printing system and / or device. The dispensing system 10 generally includes a hot end or a dispensing head 100 (e.g., a nozzle and associated dispensing elements) coupled to a gantry 16 that is movable over a base plate 12. For example, a dispensing head 100 is shown in further detail in FIGS. 2A-2D. FIGS. ID and IE show the dispensing head 100 without a protective cover, in contrast with FIGS. 1 A-1C. The dispensing head 100 is generally configured to dispense a melted material onto the base plate 12 as further described herein.

[0050] The dispensing system 10 is configured to produce an object based on a set of instructions. For example, the dispensing system 10 is configured to dispense a material (e.g., a melted filament material) in one or more layers onto the base plate 12. The base plate 12 is configured to receive and support a material (e.g., a melted filament material) as the object is produced.

[0051] As shown in FIG. 1 A, the dispensing system 10 includes a first rail 14 supporting the base plate 12. The first rail 14 includes at least one linear actuator (not shown) or other controllably moveable portion supporting the base plate 12. Thus, the base plate 12 is controllably moveable along the first rail 14 (e.g., in a first or second direction along the first rail 14). However, in other implementations of the dispensing system, the base plate may be stationary.

[0052] The dispensing system 10 further includes a gantry 16 extending above the base plate 12. The gantry 16 includes one or more members and / or rails configured to support the dispensing head 100. The gantry 16 also provides for controlled motion of the dispensing head100 relative to the base plate 12. For example, the gantry 16 includes two vertical rails 18a and 18b spaced apart from each other. The gantry 16 further includes a second rail 20 extending between and coupled to each of the vertical rails 18a, 18b. The dispensing head 100 is coupled to a portion of the second rail 20.

[0053] The second rail 20 includes at least one linear actuator (not shown) or another controllably moveable portion supporting the dispensing head 100. The dispensing head 100 is controllably moveable along the second rail 20 (e.g., in a first or second direction along the second rail 20). In particular, the second rail 20 extends in a direction perpendicular to the first rail 14. The dispensing head 100 is moveable in a plane (e.g., in an x-direction and a y-direction) relative to the base plate 12. However, in other implementations, the base plate may be stationary while the dispensing head is moveable along two or more rails in an x-direction and a y-direction.

[0054] The vertical rails 18a, 18b include at least one linear actuator (not shown) or other controllably moveable portion supporting the second rail 20. The second rail 20 is controllably moveable along the vertical rails 18a, 18b (e.g., in a first or second direction along the vertical rails 18a, 18b). In particular, the vertical rails 18a, 18b extend in a direction perpendicular to both the first rail 14 and the second rail 20 (e.g., a z-direction). The vertical rails 18a, 18b are configured to vary the height of the dispensing head 100 relative to the base plate 12. However, in other implementations, a different arrangement or orientation of the gantry members may be provided to move the dispensing head in 3 or more degrees of freedom relative to the base plate.

[0055] The dispensing system 10 further includes a controller 30 in electronic communication (e.g., wired or wireless) with each of the linear actuators of the gantry and / or rails and the dispensing head 100. The controller 30 includes a processor 32 and a memory 34 storing instructions thereon that, when executed by the processor 32, cause the dispensing head 100 to move relative to the base plate 12. For example, the memory 34 may include instructions for printing an object along with the associated movements of the dispensing head 100. The memory 34 may include instructions for customized settings or controls for the dispensing system 10 such as a temperature of the filament material, a speed of feeding the filament material, a calibration metric for the components, or any other setting commonly associated with 3D printing devices.

[0056] The dispensing system 10 further includes a user interface 36 in electronic communication with the controller 30. The user interface 36 may include a touch screen and / orone or more buttons. The user interface 36 may be configured to accept user inputs regarding a printing operation and adjust a portion of the dispensing system 10 based on those user inputs. The user interface 36 may communicate information about a printing operation to a user (e.g., via the screen).

[0057] The dispensing system 10 further includes a primary power source (e.g., a standard 120V plug or another household plug). The primary power source is configured to provide power to the user interface 36, the controller 30, the gantry 16, and the actuators associated with the gantry 16 and / or rails 14, 18a, 18b, 20. The dispensing system 10 further includes a secondary power source coupled to the dispensing head 100 to provide power to the heating elements thereof, as further described herein.

[0058] The dispensing head 100 shown in FIGS. 2A-2D, which is also shown in the dispensing system 10 of FIGS. 1A-1E, is generally configured to accept, melt, and dispense a filament material onto the base plate 12. For example, a filament material may be disposed on a spool adjacent to and / or attached to a portion of the dispensing system 10. The spool is configured to deliver a constant feed of filament material to the dispensing head 100. The dispensing head 100 of the present disclosure is capable of melting and dispensing a metal filament material (e.g., an aluminum alloy), as further described herein.

[0059] The dispensing head 100 includes a dispensing portion 102 and a power portion 104, as shown in FIGS. 1B-1D. The dispensing portion 102 and the power portion 104 of the dispensing head 100 are coupled to each other by a mounting device and / or bracket(s). The brackets shown are customized to the particular shape and arrangement of the dispensing head 100 along with the dispensing system 10 and the rail to which the dispensing head is coupled. Other configurations of the mounting bracket system are contemplated by this disclosure.

[0060] While the dispensing portion 102 and the power portion 104 move together relative to the base plate 12, they serve different functions of the dispensing head 100. In particular, the power portion 104 is coupled to the secondary power source and may include a controller or other electrical component configured to deliver proper power to the dispensing portion 102. In some implementations, the dispensing head 100 consumes less than 150W of power. The dispensing portion 102 is configured to receive power from the power portion 104 and physically accept and dispense the filament material onto the base plate 12. The dispensing head includes a housing or protective covering 199 shielding the dispensing portion 102, as shown inFIGS. 1 A-1C but removed in FIG. ID. Throughout this example, reference to the dispensing head 100 includes reference to the dispensing portion 102 of the dispensing head 100.

[0061] The dispensing head 100 generally includes a hot portion 106 and a cold portion 108 coupled to each other, as shown in FIG. 2A. A filament material is configured to extend first through the cold portion 108 and then through the hot portion 106. For example, a feeding tube 109 may extend from a spool of material to a channel defined by the cold portion 108 of the dispensing head 100. The feeding tube 109 is configured to guide the filament material into the cold portion 108 and then the hot portion 106 of the dispensing head 100. The feeding tube 109 may only extend partially into the cold portion 108, which may be sufficient for introducing the filament material into the dispensing head 100.

[0062] The hot portion 106 of the dispensing head 100 includes an outer tube 110, a nozzle 130, an inner tube 140, and a conductive wire 150. The outer tube 110 extends from a first end 112 to a second end 114 of the outer tube 110. The first end 112 is spaced apart from the second end 114 along a central longitudinal axis 101. As shown in FIG. 2A, an outer surface 116 of the outer tube 110 defines a shoulder 118 adjacent the first end 112 of the outer tube 110. An inner surface 120 of the outer tube 110 defines a central channel 122.

[0063] The central channel 122 extends from an opening on the first end 112 to an opening on the second end 114 of the outer tube 110. The central channel 122 is aligned with the central longitudinal axis 101. The inner surface 120 defines a shoulder 124 adjacent to the second end 114 of the central channel 122. Thus, the central channel 122 adjacent the second end 114 has a smaller diameter than the central channel 122 adjacent the first end 112 of the outer tube 110.

[0064] The outer tube 110 comprises a ceramic material. However, in other implementations, the outer tube may include any other material configured to withstand high temperatures and / or having high heat resistance.

[0065] As shown in FIGS. 2A and 2B, the nozzle 130 includes a first end 132 and a second end 134 opposite and spaced apart from the first end 132 along the central longitudinal axis 101. The nozzle 130 defines a nozzle channel 136 extending from an opening on the first end 132 to an opening on the second end 134 of the nozzle 130. The nozzle 130 includes an outer surface 138 with at least one portion that is tapered from first end 132 to the second end 134. Thus, a portion of the outer surface 138 of the nozzle 130 adjacent to the first end 132 has a diameter wider than that of a portion of the nozzle adjacent to the first end 132. In other implementations,the taper of the outer surface of the nozzle may be additionally or alternatively a step or a shoulder.

[0066] The nozzle 130 is insertable into the central channel 122 of the outer tube 110. Thus, the nozzle 130 is aligned with the central longitudinal axis 101. As shown in FIG. 2A, the nozzle 130 is at least partially disposed within the central channel. In particular, the second end 134 of the nozzle 130 extends through the opening on the first end 112 of the outer tube 110, through the central channel 122, and exits through the opening on the second end 114 of the outer tube 110. The shoulder 124 on the inner surface 120 of the outer tube 110, along with the tapered section of the outer surface 138 of the nozzle 130, prevents the nozzle 130 from falling through the central channel 122 of the outer tube 110. However, in other implementations, the nozzle may extend a lesser extent from, or may be recessed within, the central channel of the outer tube.

[0067] The nozzle 130 includes a ferromagnetic material, such as steel. Thus, the nozzle 130 is configured to react to an applied electromagnetic field. The nozzle 130 can also withstand high temperatures (e.g., up to or exceeding 1000 degrees Fahrenheit) without excessive deformation or loss of structural integrity.

[0068] The inner tube 140 includes a proximal end 142 and a distal end 144 opposite and spaced apart from the proximal end 142 along the central longitudinal axis 101. The inner tube 140 defines a dispensing channel 146 extending from an opening on the proximal end 142 to an opening on the distal end 144 of the inner tube 140. The inner surface of the inner tube 140 defining the dispensing channel 146 is generally straight and cylindrical. The opening on the distal end 144 of the inner tube 140 is configured to expel a filament material from the dispensing channel 146 as further described herein.

[0069] The outer surface of the inner tube 140 includes a wider diameter portion adjacent to the proximal end 142. A shoulder 148 is defined by the wider diameter portion adjacent to the proximal end 142. The inner tube 140 is insertable at least partially into the nozzle channel 136 of the nozzle 130. In particular, the inner tube 140 extends through the opening on the first end 132 of the nozzle 130, through the nozzle channel 136, and extends out of the opening on the second end 134 of the nozzle 130. As shown in FIG. 2A, the shoulder 148 abuts the first end 132 of the nozzle 130 to set the distance that the distal end 144 extends from the nozzle channel 136.

[0070] The inner tube 140 includes a graphite material. However, in other implementations, the inner tube includes any other material configured to withstand high temperatures and having good thermal conductivity. The inner surface of the inner tube 140 is configured to provide asurface to which the melted or melting filament material does not stick (e.g., a low friction surface or a surface to which the metal alloy filament will not weld).

[0071] As shown in FIG. 2 A, the conductive wire 150 is wound around the outer surface 116 of the outer tube 110 several times to define an inductive coil 152. The inductive coil 152 defines an inductive channel 154 therein. Thus, at least a portion of the outer tube 110, the nozzle 130, and the inner tube 140 are disposed within the inductive channel 154. The shoulder 118 on the outer surface 116 of the outer tube 110 provides a stopping point for the inductive coil 152 preventing sliding of the outer tube 110 relative to the inductive coil 152.

[0072] The conductive wire 150 - and the inductive coil 152 formed thereby - is coupled to the power portion 104 of the dispensing head 100. As shown in FIG. ID, the conductive wire 150 extends from the inductive coil 152 toward the power portion 104. A power source (e.g., the secondary power source) is coupled to the conductive wire 150 to provide a voltage and / or current therein.

[0073] As shown in FIG. ID, the power portion 104 includes a toroidal transformer around which the conductive wire 150 is wrapped. The transformer in the power portion 104 of the dispensing head 100 is generally configured to step up the voltage flowing through the conductive wire 150. However, in other implementations, a different power source and / or set of electrical components may be used to provide an adequate voltage in the conductive wire 150.

[0074] The inductive coil 152 is configured to produce an electromagnetic field within the inductive channel 154 when voltage is applied to the conductive wire 150. The electromagnetic field heats the nozzle 130, which includes ferromagnetic material, via inductive heating. The nozzle 130 heats up to, for example, greater than 1000 degrees Fahrenheit. Heat is transferred from the nozzle 130 radially inward through the inner tube 140 and into the filament material disposed therein. Thus, the filament material has a lower melting point than then nozzle 130.

[0075] The filament material passes through the feeding tube 109, the cold portion 108, and into the dispensing channel 146 of the inner tube 140. Once sufficiently heated within the inner tube 140, the molten material is dispensed and expelled from the proximal end 142 of the dispensing channel 146 (e.g., onto a base plate 12). The inductive coil 152 thus provides inductive heating that indirectly melts, via the ferromagnetic nozzle 130, the metal filament material, producing a metal-material enabled 3D printing head.

[0076] The cold portion 108 of the dispensing head 100 is coupled to the hot portion 106 and generally provides heat dissipation and isolation for the dispensing head 100. First, an insert 160 is disposed partially within the proximal end 142 of the inner tube 140, as shown in FIG. 2C. FIG. 4 A shows various views of the insert 160 according to one implementation. The insert 160 includes two shoulders or discs extending from a central portion (e.g., approximating an I- shaped cross section). The insert 160 defines a channel aligned with the central longitudinal axis 101 and configured to feed the filament material from the cold portion 108 to the hot portion 106. The insert 160 generally facilitates the delivery of the filament material into the outer tube 110, nozzle 130, and / or the inner tube 140 in a substantially linear manner. The insert 160 includes a graphite material. However, in other implementations, the insert may include a different rigid material.

[0077] A connector 164 is coupled to the insert 160 (e.g., via screw threads). The connector 164 is shown in FIGS. 2A-2B and FIG. 4B. The connector 164 comprises an aluminum or other rigid material. The connector 164 couples the insert 160 to a heat brake 170. The heat brake 170 includes a metal or other highly conductive material. The heat brake 170 acts as a thermal barrier, ensuring the filament material is melted only in the intended area near the nozzle 130. Together, the heat brake 170, the insert 160, and the connector 164 separate the hot portion 106 having the nozzle 130 from the relatively colder components of the cold portion 108 along with the filament entry point. The cold portion 108 of the dispensing head 100 generally prevents the filament material from softening prematurely and causing jams.

[0078] Furthermore, the cold portion 108 of the dispensing head 100 includes a heat sink 174, as shown in FIGS. 2 A and 2C. The heat sink 174 includes fins configured to expel heat from the dispensing head 100 into the surrounding air. In some implementations, a fan or other air moving device is coupled to the dispensing head adjacent to the heat sink 174 to facilitate heat dissipation.

[0079] FIGS. 3A and 3B show another example of a dispensing head 100a that is substantially similar to that of the dispensing head 100. As shown in the prototype image of FIG. 3B, the conductive wire 150 has not yet been wound around the outer tube 110 to form the inductive coil 152. The dispensing head 100a may include a drive extruder (e.g., spools or gears) coupled to a portion thereof to facilitate straight feeding of the filament material.

[0080] FIG. 3C shows another example of a dispensing system 10a that is substantially similar to that of the dispensing system 10. The dispensing system 10a includes a version of thedispensing head 100a with additional features shown. For example, the dispensing head 100a in FIG. 3C includes a fan 180 coupled to a power source and configured to direct an airflow towards the heat sink 174 of the cold portion of the dispensing head 100a. The dispensing head 100a in FIG. 3C further includes a drive system 190 on an upper portion of the dispensing head 100a. The drive system 190 is directly aligned with the central longitudinal axis 101 of the dispensing head 100a. The drive system 190 may include one or more rollers or gears adjacent to a feeding tube and configured to deliver the filament material into the channel of the dispensing head 100a.

[0081] A method of dispensing a filament material (e.g., a metal alloy filament material) is disclosed. The dispensing system 10 having the dispensing head 100 (or a similar dispensing head as described herein) is provided. The dispensing head 100 may be coupled to an existing 3D printer device or a gantry system thereof.

[0082] In use, an electromagnetic field is produced within the inductive channel 154 of the inductive coil 152. The electromagnetic field is produced via the delivery of energy (e.g., an applied voltage and / or current flow) from the power source to the conductive wire 150 and the inductive coil 152 formed thereby. The resulting electromagnetic field heats the nozzle 130 of the dispensing head 100 via inductive heating.

[0083] The filament material (e.g., an aluminum alloy) is fed from a source (e.g., a spool) to the dispensing head 100. In some implementations, a feeding device, such as one or more rollers, drives the filament material from the spool to the dispensing head 100. The filament material is fed into a channel defined by the cold portion 108 of the dispensing head 100 and further into a channel defined by the hot portion 106 of the dispensing head 100. The filament material is ultimately fed into the dispensing channel 146 of the inner tube 140.

[0084] The filament material is melted within the dispensing channel 146 via heat transfer from the nozzle 130 to the filament material within the inner tube 140. In particular, the conductive properties of the inner tube 140 facilitate heat transfer radially inward from the nozzle 130 to the filament material. The insulative properties of the outer tube 110 may contribute to the efficiency of the heat transfer.

[0085] The melted filament material is dispensed and / or expelled from the dispensing opening on the distal end 144 of the dispensing channel 146 of the inner tube 140. For example, the melted filament material is dispensed onto the base plate 12 of the dispensing system 10.

[0086] The dispensing system 10 controllably moves the dispensing head 100 and the filament material expelled therefrom. For example, the actuators associated with the gantry 16 and / or the rails thereof controllably move the dispensing head 100 relative to the base plate 12 as the filament material is expelled. Movement of the dispensing head 100 relative to the base plate 12 produced a 3D printed product from the melted filament material (e.g., a metal object comprising one or more layers).

[0087] Additional details and exemplary drawings with exemplary dimensions for each of the graphite insert, the steel tube, and the ceramic tube are provided in the drawings. Any dimensions shown or described by this disclosure are exemplary only. While the various elements of the dispensing head are referred to herein with their material type, other implementations of the present disclosure may provide for different material usage. For example, rather than ceramic, the outer tube of the device may be formed of other low conductivity materials. For example, rather than steel, the nozzle of the device may be formed of other high conductivity and high melting point materials (e.g., metal alloys). For example, rather than graphite, the insert within the nozzle of the device may be formed by other high conductivity materials.Experimental Study and Results

[0088] FIGS. 5A-5F show images of an experimental dispensing head (e.g., similar to the dispensing head 100) coupled to a dispensing system (e.g., similar to the dispensing system 10). According to one study, an aluminum alloy filament material was fed into a dispensing head having an inductive heating coil.

[0089] As shown in FIGS. 5A-5D, a bead or sphere of melted filament material is formed at the distal end 144 of the inner tube 140. This study showed that the power applied to the inductive coil 152 was sufficient to melt the filament material and expel a portion from the inner tube 140 of the dispensing head 100. The sphere of material cooled at the tip in this study, but adjustments were made to increase the rate of material expulsion in subsequent tests.

[0090] According to another study, a dispensing system 10 moved a dispensing head 100 in a predetermined pattern to evaluate the production of a layer of material. As shown in FIG. 5E, a line of filament material was dispensed onto the base plate 12. As shown in FIG. 5F, a shape - shown as a hexagon - was produced on the base plate 12. Importantly, the dispensed material did not stick to the nozzle 130 nor the inner tube 140. This study also showed that the expelledmetal filament material can produce a predetermined shape via movement of the dispensing head 100 relative to the base plate 12.Additional Implementations and Background Discussion

[0091] As shown in FIG. 6A, according to some implementations, the conductive wire forming the inductive coil is hollow and configured to provide a fluid flow therethrough. For example, water or a different fluid (e.g., coolant) may facilitate heat transfer from away from the dispensing head (e.g., away from the nozzle through the outer tube). A water- or fluid-cooled implementation of the dispensing head may implement a pumping system (e.g., a peristaltic pump) configured to urge fluid along a fluid loop coupled with the conductive wire. In other implementations, a heat exchanger may be in communication or contact with the conductive wire and / or the fluid flowing therethrough so that the fluid may be cooled.

[0092] As shown in FIG. 6B, according to some implementations of the dispensing head, a shielding gas (e.g., argon) may be provided at the nozzle tip. For example, a flow of shielding gas may be provided through the dispensing head, along the ceramic tube, and around the nozzle. The shielding gas may be configured to reduce rust / oxidation of the nozzle.Configuration of Certain Implementations

[0093] The construction and arrangement of the systems and methods as shown in the various implementations are illustrative only. Although only a few implementations have been described in detail in this disclosure, many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes, and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.). For example, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. Accordingly, all such modifications are intended to be included within the scope of the present disclosure. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative implementations. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions, and arrangement of the implementations without departing from the scope of the present disclosure.

[0094] The present disclosure contemplates methods, systems, and program products on any machine-readable media for accomplishing various operations. The implementations of the present disclosure may be implemented using existing computer processors, or by a specialpurpose computer processor for an appropriate system, incorporated for this or another purpose, or by a hardwired system. Implementations within the scope of the present disclosure include program products including machine-readable media for carrying or having machine-executable instructions or data structures stored thereon. Such machine-readable media can be any available media that can be accessed by a general purpose or special purpose computer or other machine with a processor. By way of example, such machine-readable media can comprise RAM, ROM, EPROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to carry or store desired program code in the form of machine-executable instructions or data structures, and which can be accessed by a general purpose or special purpose computer or other machine with a processor.

[0095] When information is transferred or provided over a network or another communications connection (either hardwired, wireless, or a combination of hardwired or wireless) to a machine, the machine properly views the connection as a machine-readable medium. Thus, any such connection is properly termed a machine-readable medium. Combinations of the above are also included within the scope of machine-readable media. Machine-executable instructions include, for example, instructions and data which cause a general -purpose computer, special purpose computer, or special purpose processing machines to perform a certain function or group of functions.

[0096] Although the figures show a specific order of method steps, the order of the steps may differ from what is depicted. Also, two or more steps may be performed concurrently or with partial concurrence. Such variation will depend on the software and hardware systems chosen and on designer choice. All such variations are within the scope of the disclosure. Likewise, software implementations could be accomplished with standard programming techniques with rule-based logic and other logic to accomplish the various connection steps, processing steps, comparison steps and decision steps.

[0097] It is to be understood that the methods and systems are not limited to specific synthetic methods, specific components, or to particular compositions. It is also to be understood that the terminology used herein is for the purpose of describing particular implementations only and is not intended to be limiting.

[0098] As used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Ranges may beexpressed herein as from “about” one particular value, and / or to “about” another particular value. When such a range is expressed, another implementation includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another implementation. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0099] “Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not. Throughout the description and claims of this specification, the word “comprise” and variations of the word, such as “comprising” and “comprises,” means “including but not limited to,” and is not intended to exclude, for example, other additives, components, integers or steps. “Exemplary” means “an example of’ and is not intended to convey an indication of a preferred or ideal implementation. “Such as” is not used in a restrictive sense, but for explanatory purposes.

[0100] Disclosed are components that can be used to perform the disclosed methods and systems. These and other components are disclosed herein, and it is understood that when combinations, subsets, interactions, groups, etc. of these components are disclosed that while specific reference of each various individual and collective combinations and permutation of these may not be explicitly disclosed, each is specifically contemplated and described herein, for all methods and systems. This applies to all aspects of this application including, but not limited to, steps in disclosed methods. Thus, if there are a variety of additional steps that can be performed it is understood that each of these additional steps can be performed with any specific implementation or combination of implementations of the disclosed methods.

Claims

WHAT IS CLAIMED IS:

1. A dispensing head comprising: an outer tube extending from a first end to a second end along a central longitudinal axis, the outer tube defining a central channel; a nozzle disposed at least partially within the central channel and defining a nozzle channel aligned along the central longitudinal axis, the nozzle comprising a ferromagnetic material; an inner tube disposed at least partially within the nozzle channel and defining a dispensing channel aligned along the central longitudinal axis, the inner tube having a distal end defining a dispensing opening configured to expel a filament material disposed within the dispensing channel; and a conductive wire wound to define an inductive coil defining an inductive channel therein, wherein at least a portion of the outer tube, the nozzle, and the inner tube are disposed within the inductive channel, wherein the conductive wire is coupled to a power source, wherein the inductive coil is configured to produce an electromagnetic field within the inductive channel that heats the nozzle, wherein heat is transferred from the nozzle to the filament material within the dispensing channel of the inner tube to melt the filament material expelled from the dispensing opening of the inner tube.

2. The dispensing head of claim 1, wherein the outer tube comprises ceramic.

3. The dispensing head of claim 1, wherein the inner tube comprises graphite.

4. The dispensing head of claim 1, wherein the nozzle comprises steel.

5. The dispensing head of claim 1, wherein the conductive wire is wound around an outer surface of the outer tube to define the inductive coil.

6. The dispensing head of claim 1, wherein heat transfer from the nozzle to the filament material within the dispensing channel is facilitated by the inner tube comprising a thermally conductive material.

7. The dispensing head of claim 1, further comprising a heat sink coupled to a hot end of the dispensing head that includes the outer tube, the nozzle, and the inner tube.

8. The dispensing head of claim 7, wherein the heat sink is coupled to the hot end of the dispensing head via a heat brake disposed therebetween.

9. The dispensing head of claim 7, wherein the heat sink is coupled to (i) the first end of the outer tube (ii) a first end of the nozzle, (iii) and / or a proximal end of the inner tube.

10. The dispensing head of claim 7, further comprising: a feeding tube extending through a channel defined through the heat sink, the feeding tube is configured to accept and guide the filament material toward the hot end of the dispensing head.

11. The dispensing head of claim 1, wherein the power source is an induction coil power source.

12. The dispensing head of claim 1, wherein the filament material is an aluminum alloy.

13. The dispensing head of claim 1, wherein the filament material is fed into the first end of the outer tube and through each of the central channel, the nozzle channel, and the dispensing channel, wherein the filament material within the dispensing channel is heated at least to a melting temperature such that liquid filament material is dispensed from the dispensing opening of the inner tube.

14. The dispensing head of claim 1, further comprising a housing covering a substantial portion of the dispensing head but exposing at least the distal end of the inner tube.

15. The dispensing head of claim 1, wherein the dispensing head is attachable to a gantry of a controllably moveable device (e.g., existing 3D printer).

16. A dispensing system comprising: a 3D printing device comprising a gantry and a base plate; anda dispensing head coupled to the gantry, the dispensing head comprising: an outer tube extending from a first end to a second end along a central longitudinal axis, the outer tube defining a central channel; a nozzle disposed at least partially within the central channel and defining a nozzle channel aligned along the central longitudinal axis, the nozzle comprising a ferromagnetic material; an inner tube disposed at least partially within the nozzle channel and defining a dispensing channel aligned along the central longitudinal axis, the inner tube having a distal end defining a dispensing opening configured to expel a filament material disposed within the dispensing channel; and a conductive wire wound to define an inductive coil defining an inductive channel therein, wherein at least a portion of the outer tube, the nozzle, and the inner tube are disposed within the inductive channel, wherein the conductive wire is coupled to a power source, wherein the inductive coil is configured to produce an electromagnetic field within the inductive channel that heats the nozzle, wherein heat is transferred from the nozzle to the filament material within the dispensing channel of the inner tube to melt the filament material expelled from the dispensing opening of the inner tube.

17. The dispensing system of claim 16, wherein the melted filament material expelled from the dispensing opening of the inner tube is deposited on the base plate of the 3D printing device.

18. The dispensing system of claim 16, wherein the dispensing head is moveable along the gantry in at least one direction relative to the base plate.

19. The dispensing system of claim 16, further comprising a controller configured to actuate the gantry to move the dispensing head in at least one direction with respect to the base plate.

20. The dispensing system of claim 16, further comprising a spool of the filament material, wherein the filament material is fed through the dispensing channel of the dispensing head.21 . A method of dispensing a filament material, the method comprising: providing a dispensing head comprising:an outer tube extending from a first end to a second end along a central longitudinal axis, the outer tube defining a central channel; a nozzle disposed at least partially within the central channel and defining a nozzle channel aligned along the central longitudinal axis, the nozzle comprising a ferromagnetic material; an inner tube disposed at least partially within the nozzle channel and defining a dispensing channel aligned along the central longitudinal axis, the inner tube having a distal end defining a dispensing opening; and a conductive wire wound to define an inductive coil defining an inductive channel therein, wherein at least a portion of the outer tube, the nozzle, and the inner tube are disposed within the inductive channel, wherein the conductive wire is coupled to a power source; producing an electromagnetic field within the inductive channel via delivery of energy from the power source to the inductive coil, wherein the resulting electromagnetic field heats the nozzle of the dispensing head; feeding the filament material into the dispensing channel of the dispensing head; melting the filament material within the dispensing channel via heat transfer from the nozzle to the filament material; and expelling the melted filament material from the dispensing opening of the inner tube.

22. The method of claim 21, wherein the filament material is a metal alloy.

23. The method of claim 21, further comprising: coupling the dispensing head to a 3D printing device; and controllably moving the dispensing head along a portion of the 3D printing device relative to a base plate thereof to produce a 3D printed product from the melted filament material.

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