System and method for generating molten metal droplets for additive manufacturing

Abstract

The present disclosure relates to a system for additive manufacturing. The system includes a frame and a CNC bed configured with the frame. A metal dispensing mechanism is configured to eject metal droplets onto the CNC bed. The metal dispensing mechanism is configured to controllably move relative to the CNC bed to manufacture an object. The metal dispensing mechanism includes a first nozzle operatively configured with the CNC bed to controllably dispense metal droplets onto the CNC bed, the nozzle being fluidly configured with a reservoir having metal. A piston is configured with the reservoir, the piston configured to push molten metal from the reservoir such that the molten metal is expelled from the reservoir toward the first nozzle. The piston is made of a thermally insulating material, and a transducer is configured with the piston to facilitate mechanical jerking of the piston to facilitate pushing of the molten metal from the reservoir.

Description

Technical Field

[0001] This disclosure relates to the field of additive manufacturing. More specifically, this disclosure relates to a system for generating molten metal droplets for additive manufacturing.

Background Art

[0002] The description of the background includes information that is helpful for understanding the present invention. It is not admitted that any of the information provided herein is prior art, or is related to the invention claimed in the current claims, or that any of the publications specifically or implicitly referenced is prior art.

[0003] In the field of additive manufacturing, drop-on-demand is one method of generating small-sized molten metal droplets for printing metal in multiple dimensions. Drop-on-demand (DoD) can be achieved using a plurality of techniques. Among all of these DoD technologies, one method of generating molten metal droplets is to use a metal piston to push molten metal by using an actuator. When using DoD, the actuator transmits movement to a piston held within the molten metal. The piston pushes the molten metal to discharge the metal from the nozzle. In this process, since the metal is in a molten state at a high temperature, the metal piston transfers heat from the molten metal pool to the actuator or transducer, causing damage due to overheating. Also, in order to protect the transducer from damage, a high-temperature-resistant transducer or a cooling system dedicated to the transducer is required. This increases the overall cost of the additive manufacturing system.

[0004] Furthermore, metal printers and polymer printers are commercially available as two separate machines due to their printing processes. Metals are printed at a higher temperature compared to the extrusion temperature of polymers. This temperature difference prevents metals and polymers from being printed together. As an alternative to the combination of metal and metal printing, conductive ink printers are commercially available that use polymers to print conductive inks. These printers print conductors onto insulating surfaces to interconnect electronic components and create functional electronic circuits. This technique is limited to printing low-power electronic circuits in 2D due to the high electrical resistance of the technique and conductive inks. This limitation can be overcome by using direct metal for printing electronic circuits in 3D and higher dimensions.

[0005] Therefore, an improved system for additive manufacturing that is free from the aforementioned problems is needed. [Overview of the project] [Problems that the invention aims to solve]

[0006] Some of the objects of this disclosure that at least one embodiment of this specification satisfies are listed below.

[0007] The purpose of this disclosure is to provide an additive manufacturing system that reduces maintenance costs because the transducer is protected from damage caused by the heat of the molten metal.

[0008] The purpose of this disclosure is to provide an additive manufacturing system that enables metal printing without requiring high-temperature transducers or dedicated cooling systems for transducers.

[0009] The purpose of this disclosure is to provide an additive manufacturing system that reduces heat loss in the introduction system by using an adiabatic piston.

[0010] The object of this disclosure is to provide an additive manufacturing system that prevents the overheating of the transducer, thereby enabling the use of many other transducers suitable for low-temperature use to generate molten metal droplets.

[0011] The purpose of this disclosure is to provide an additive manufacturing system that enables a combination of metal and polymer for printing electronic circuits together with their insulators in multiple dimensions, and for printing metal and polymer parts in multiple dimensions such as 2D and 3D. [Means for solving the problem]

[0012] This disclosure relates to the field of additive manufacturing. More specifically, this disclosure relates to a system for generating molten metal droplets for additive manufacturing.

[0013] One aspect of the present disclosure relates to a system for additive manufacturing. The system includes a frame and a computer numerical control (CNC) bed configured with the frame for supporting an object to be manufactured on top of it. The CNC bed is configured to move in a multidimensional axis. A metal distribution mechanism is configured to discharge metal droplets onto the CNC bed. The metal distribution mechanism is configured to move controllly relative to the CNC bed to manufacture an object. The metal distribution mechanism includes a first nozzle functionally configured with the CNC bed to controllly distribute metal droplets onto the CNC bed, the nozzle being fluidically configured with a reservoir containing metal. A piston is configured with the reservoir and is configured to push molten metal out of the reservoir so that the molten metal is discharged from the reservoir toward the first nozzle. The piston is made of a thermally insulating and electrically insulating material, and a transducer is configured with the piston so that the piston can discharge molten metal from the reservoir.

[0014] In one embodiment, the thermal insulation material may include borosilicate glass.

[0015] In one embodiment, the reservoir may be made of aluminum and is configured with a metal spool for receiving metal.

[0016] In one embodiment, the system may include an induction heater configured around the reservoir to melt the metal in the reservoir.

[0017] In one embodiment, the transducer of the system may be either a magnetostrictive transducer or a piezoelectric transducer.

[0018] In one embodiment, the transducer is electrically configured with a voltage source that receives input voltage pulses to facilitate the mechanical jerking of a piston.

[0019] In one embodiment, the system may include a polymer extruder configured to extrude a polymer onto a CNC bed through a second nozzle configured with the CNC bed in order to manufacture an object, wherein the polymer extruder is configured to move relative to the CNC bed and a metal distribution mechanism.

[0020] In one embodiment, the polymer extruder may be configured with a polymer spool for receiving the polymer.

[0021] In one embodiment, the system may include a control unit having a controller operably combined with a CNC bed, a metal distribution mechanism, and a polymer extruder, the control unit being configured to control the relative motion between the bed, the metal distribution mechanism, and the polymer extruder, and the control unit being configured to control a series of operations of the CNC bed, the metal distribution mechanism, and the polymer extruder.

[0022] In one embodiment, the object may be manufactured by a series of processes including the extrusion of polymers from a polymer extruder and the distribution of molten metal from a metal distribution mechanism.

[0023] Various objectives, features, aspects, and advantages of the subject matter of the present invention will become more apparent from the following detailed description of the preferred embodiments, together with the accompanying drawings in which like numerals represent like components.

Advantages of the Invention

[0024] The proposed invention provides a cost-effective additive manufacturing system by protecting the transducer from damage caused by the heat of molten metal.

[0025] The proposed invention provides an additive manufacturing system with low maintenance costs by protecting the transducer from damage caused by the heat of molten metal.

[0026] The proposed invention provides an additive manufacturing system that enables printing of metals without the need for high-temperature transducers or dedicated cooling systems for transducers.

[0027] The proposed invention provides an additive manufacturing system that reduces heat loss in an induction heating system using a heat-insulating piston.

[0028] The proposed invention provides an additive manufacturing system that can prevent heating of the transducer, enabling the use of many other transducers suitable for low-temperature use to generate molten metal droplets.

[0029] The proposed invention provides an additive manufacturing system capable of multi-dimensional printing of a combination of metal and polymer for printing an electronic circuit together with its insulator in multiple dimensions and printing metal together with a polymer part in multiple dimensions.

Brief Description of the Drawings

[0030] The accompanying drawings are included to provide a further understanding of this disclosure and are incorporated herein and constitute part thereof. The drawings illustrate exemplary embodiments of this disclosure and, together with their description, help to illustrate the principles of this disclosure. The drawings are for illustrative purposes only and do not limit this disclosure.

[0031] In drawings, similar components and / or features may have the same reference numeral. Furthermore, different components of the same type may be distinguished by adding a second reference numeral after the reference numeral to differentiate between similar components. Where only the first reference numeral is used herein, the description is applicable to any one of the similar components having the same first reference numeral, regardless of the second reference numeral.

[0032] Figure 1 shows an illustrative diagram of a metal additive manufacturing system according to one embodiment of the present disclosure.

[0033] Figure 2 shows an exemplary diagram of a metal distribution mechanism according to one embodiment of the present disclosure.

[0034] Figure 3 shows an exemplary diagram of a crucible in a metal distribution mechanism according to one embodiment of the present disclosure. [Modes for carrying out the invention]

[0035] The following is a detailed description of embodiments of the present disclosure shown in the accompanying drawings. The embodiments are described in sufficient detail to clearly convey the present disclosure. However, the totality of the details provided is not intended to limit the expected variations of the embodiments, but rather to cover all modifications, equivalents, and substitutions that fall within the scope of the present disclosure as defined by the accompanying claims.

[0036] The following description includes many specific details to provide a complete understanding of embodiments of the present invention. It will be apparent to those skilled in the art that embodiments of the present invention can be carried out without some of these specific details.

[0037] This disclosure relates to the field of additive manufacturing. More specifically, this disclosure relates to a system for generating molten metal droplets for additive manufacturing.

[0038] This disclosure describes in detail an additive manufacturing system. The system includes a frame and a computer numerical control (CNC) bed configured with the frame for supporting the object to be manufactured. The CNC bed is configured to move in a multidimensional space, and a metal distribution mechanism is configured to discharge metal droplets onto the CNC bed. The metal distribution mechanism is configured to move controllly relative to the CNC bed to manufacture the object. The metal distribution mechanism includes a first nozzle functionally configured with the CNC bed to controllly distribute metal droplets onto the CNC bed, the nozzle being fluidically configured with a reservoir containing metal. A piston is configured with the reservoir and is configured to push molten metal out of the reservoir so that the molten metal is discharged from the reservoir toward the first nozzle. The piston is made of a thermally insulating and electrically insulating material, and a transducer is configured with the piston so as to transmit mechanical jerking, enabling the piston to push the molten metal out of the reservoir.

[0039] In one embodiment, the heat insulating material may include borosilicate glass.

[0040] In one embodiment, the reservoir may be made of aluminum and is configured with a metal spool for receiving metal.

[0041] In one embodiment, the system may include an induction heater configured around the reservoir to melt the metal in the reservoir.

[0042] In one embodiment, the transducer of the system may be either a magnetostrictive transducer or a piezoelectric transducer.

[0043] In one embodiment, the transducer may be electrically configured with a voltage source to receive input voltage pulses to facilitate the mechanical jerking of the piston.

[0044] In one embodiment, the system may include a polymer extruder configured to extrude a polymer onto a CNC bed through a second nozzle functionally configured with the CNC bed in order to manufacture an object, wherein the polymer extruder is configured to move relative to the CNC bed and a metal distribution mechanism.

[0045] In one embodiment, the polymer extruder may be configured with a polymer spool for receiving the polymer.

[0046] In one embodiment, the system may include a control unit having a controller operably combined with a CNC bed, a metal distribution mechanism, and a polymer extruder, the control unit being configured to control the relative motion between the bed, the metal distribution mechanism, and the polymer extruder, and the control unit being configured to control a series of operations of the CNC bed, the metal distribution mechanism, and the polymer extruder.

[0047] In one embodiment, the object may be manufactured by a series of steps: extruding a polymer from a polymer extruder and distributing molten metal from a metal distribution mechanism.

[0048] Figure 1 illustrates an example of a metal additive manufacturing system according to one embodiment of the present disclosure.

[0049] Figure 2 shows an exemplary diagram of a metal distribution mechanism according to one embodiment of the present disclosure.

[0050] Figure 3 shows an exemplary diagram of a crucible in a metal distribution mechanism according to one embodiment of the present disclosure.

[0051] As shown in the figure, the additive manufacturing system 100 may include a frame "F". A computer numerical control (CNC) bed 118 may be configured to move with the frame F, and the CNC bed 118 may be configured to support an object to be manufactured on it. The CNC bed 118 may be configured to move in a multidimensional space. A metal distribution mechanism 104 may be configured to discharge metal droplets onto the CNC bed 118. The metal may be any low-melting-point conductive metal such as copper or aluminum, but is not limited thereto. The metal distribution mechanism 104 may be configured to move controllly relative to the CNC bed 118 to manufacture an object. The object may include but is not limited to articles or electronic circuits. The system 100 may include a polymer extruder 102 which may be configured to extrude a polymer onto the CNC bed 118 to manufacture an object. The polymer extruder 102 may be configured to move relative to the CNC bed 118 and the metal distribution mechanism 104. The polymer extruder 102 may also be configured with a polymer spool 106 for receiving the polymer.

[0052] In one embodiment, the metal distribution mechanism 104 may include a first nozzle 122, which may be positioned perpendicular to the CNC bed 118, but is not limited thereto. The first nozzle 122 may have a hole with a diameter of about 1 to 300 microns and may be configured to controllly distribute metal droplets onto the CNC bed 118. The first nozzle 122 may be made of stainless steel, but is not limited thereto. The first nozzle 122 may be fluidly configured with a reservoir 110 having metal inside. A piston 116 may be configured with the reservoir 110 and may be configured to push molten metal from the reservoir 110 and discharge the molten metal from the reservoir 110 toward the first nozzle 122. The piston 116 may be made of an insulating material such as borosilicate glass or ceramic, but is not limited thereto. A transducer 120 is configured with the piston to facilitate the mechanical jerking of the piston in order to facilitate the extrusion of molten metal from the reservoir 110. The polymer extruder 102 may be configured to extrude a polymer onto the CNC bed 118 through a second nozzle 124 that is fluidly configured with the polymer extruder 102. The first nozzle 122 and the second nozzle 124 may be functionally configured with the CNC bed, or they may be configured in any direction (e.g., perpendicular to) the CNC bed. The positions of the first nozzle 122 and the second nozzle 124 may be changed (manually or automatically) to manufacture the object.

[0053] In one embodiment, the reservoir 110 may be made of aluminum, but is not limited thereto, and the reservoir may be configured with a metal spool 108 for receiving metal. The system 100 may include an induction heater 114 having a coil 112 which may be configured around the reservoir 110 to melt the metal in the reservoir 110. The transducer 120 may be a magnetostrictive material-based transducer or a piezoelectric transducer which can convert electrical signals into mechanical motion, but is not limited thereto. The transducer 120 may be electrically configured with a voltage source (not shown) to receive an input voltage pulse to facilitate mechanical jerking of a piston. The transducer 120 can convert the voltage pulse into mechanical jerking which may be transmitted to a piston 116 to facilitate the discharge of molten metal from the reservoir 110.

[0054] In one embodiment, mechanical jerking of the transducer 120 perpendicular to the CNC bed 118 can move an insulated piston 116 toward the crucible or reservoir 110. The piston 116, made of insulating material, is used to prevent damage to the transducer 120 due to heat transfer from the reservoir 110. The insulated piston 116 can act as an insulator between the heated molten metal and the transducer 120. Each pulse from a waveform generator (also called a voltage source) can provide one molten metal droplet to be discharged from a first nozzle 122.

[0055] In one embodiment, to print metal in multiple dimensions, the metal can first be melted in a reservoir 110 using a zero-voltage switching-based induction heating circuit 114 and induction coil 112. A low-melting-point metal (such as, but not limited to, solder alloy - Sn96.5Ag3.5) can be used to print the workpiece in multiple dimensions. Metal printing requires an optimal temperature for the molten metal pool in the reservoir 110. The temperature of the reservoir 110 can be maintained using, but not limited to, a K-type thermocouple. Temperature sensors can be used to sense and maintain the temperature data of the reservoir 110 in a database, and a computer-controlled algorithm can be used to compare corresponding changes in the temperature data. The temperature data can be used to maintain a predetermined level of molten metal in the reservoir 110, and when that level is reached, a piston 116 can be activated to begin dispensing molten metal droplets from the first nozzle 122.

[0056] In one embodiment, the size of the molten metal discharged from the first nozzle 122 may depend on the size of the nozzle hole, the gap 126 between the piston 116 and the first nozzle 122, the level of molten metal in the crucible, the amplitude, duration, and frequency of the pulse applied to the transducer 120, or a combination thereof. The droplet size can be changed by changing any of the parameters discussed to select the optimal droplet size. The system may include a control unit having a controller that can be configured to work with the metal distribution mechanism 104, a heating system, a waveform generator, a temperature sensor, and the magnetostrictive transducer 120. The distribution of metal droplets can be controlled using the controller. The types of objects may include, but are not limited to, electronic circuits, PCBs, and multidimensional objects.

[0057] In one embodiment, the CNC bed 118 can be associated with a multi-axis computer numerical control (CNC) motorized system. The CNC system can facilitate the movement and orientation of the workpiece in space in three dimensions. The control unit can be configured to actuate the movement and reorientation of the workbench in three dimensions based on the design file (CAD design file) of the object. During the metal printing process, heat can be transferred from the molten metal pool to the glass piston and the surrounding area (air). Because borosilicate glass has poor thermal conductivity, it does not transfer heat from the molten metal pool to the transducer 120. This prevents heat damage to the transducer 120 and enables metal printing without the need for a high-temperature resistant transducer 120 or a dedicated cooling system for the transducer.

[0058] In one embodiment, the system may include a control unit having a controller operably combined with a CNC bed, a metal distribution mechanism, and a polymer extruder, the control unit configured to control the relative motion between the bed, the metal distribution mechanism, and the polymer extruder. The control unit is configured to control a sequence of operations of the CNC bed, the metal distribution mechanism, and the polymer extruder. Since the interaction between the molten metal and the polymer during metal-polymer composite printing is not simple, and the high-temperature molten metal can melt / damage the polymer layer, it is important to control the operating sequence of the metal distribution mechanism 104 and the polymer extruder. The polymer extruder 102 may be configured to extrude the polymer first as a base for printing the metal.

[0059] In one embodiment, the polymer may include, but is not limited to, PLA / ABS (polylactic acid / acrylonitrile butadiene styrene). The proposed additive manufacturing system may include one or more temperature sensing devices configured with an induction heater and one or more flow sensing devices configured with a first nozzle and a second nozzle. The one or more temperature sensing devices and the one or more flow sensing devices may be configured to operate together with a controller, which may be configured to control the temperature of the induction heater and the flow rate control of the first nozzle and the second nozzle based on inputs from the one or more temperature sensing devices and the one or more flow sensing devices.

[0060] In one embodiment, the induction heater 114 can be configured to heat the metal for printing, while the piston 116 remains cool due to its insulating properties. This reduces power loss in the induction heating system and prevents the transducer 120 from overheating. Preventing transducer overheating allows the use of many other transducers suitable for low-temperature operation to generate molten metal droplets, and the borosilicate-based glass piston 116, along with combinations of different operating transducer systems, can be used to generate molten metal droplets for metal additive manufacturing applications.

[0061] In one embodiment, the proposed system 100 can print mechanical parts using only metal and multidimensional electronic circuits using metal. Molten metal is deposited onto the workpiece / CNC bed 118 by generating micron-sized metal droplets using metal droplet on-demand technology. The proposed system 100 can provide a simple and easily controllable operating mechanism. In one embodiment, the system 100 can be fitted with one or more additional heads for depositing / extruding additional polymer, metal, or ceramic materials. This enables the manufacture of multi-material parts, including but not limited to electronic circuits and functionally graded materials.

[0062] The proposed system can extrude molten metal in the form of micron-sized droplets for additive manufacturing applications combining metals and polymers. Since these droplets can be generated at sub-millimeter size and low temperatures, this opens up the field of integrated metal-polymer additive manufacturing in a single system. One potential application is printing electronic circuits where the polymer acts as an insulator and metal tracks interconnect passive and active electronic components in 2D, 3D, and multidimensional ways.

[0063] Furthermore, when interpreting the specification, all terms must be interpreted as broadly as possible in context. In particular, the terms “constitute” and “constitute” should be interpreted in a non-exclusive manner as referring to an element, component, or step, indicating that the referenced element, component, or step may exist, be used, or be combined with other elements, components, or steps that are not explicitly referenced. If a claim in the specification refers to at least one selected from the group consisting of A, B, C, ..., and N, the text should be interpreted as requiring only one element from the group, rather than A plus N, or B plus N, etc.

[0064] Although various embodiments of the present invention have been described above, other further embodiments of the present invention may be devised without departing from the basic scope of the present invention. The scope of the present invention is determined by the following claims. The present invention is not limited to the embodiments, modifications, or examples described, but are included so as to enable those skilled in the art to practice and use the present invention in combination with available information and knowledge.

Claims

1. Frame and, A computer numerical control (CNC) bed, configured with the frame, for supporting the object to be manufactured from above, A metal distribution mechanism configured to discharge metal droplets onto the CNC bed and to move in a controllable manner relative to the CNC bed in order to manufacture an object; Equipped with, The aforementioned metal distribution mechanism is A first nozzle, functionally configured with the CNC bed and fluidly configured with a metal reservoir, for controllably distributing metal droplets onto the CNC bed, A piston made of an electrically insulating thermal insulation material is configured to push the molten metal out of the reservoir so that the molten metal is discharged from the reservoir toward the first nozzle, and is configured to be used together with the reservoir, The piston is configured together with a transducer so that the piston can discharge molten metal from the reservoir. Equipped with, Additive manufacturing system.

2. The additive manufacturing system according to claim 1, wherein the electrically insulating thermal insulation material is made of borosilicate glass.

3. The additive manufacturing system according to claim 1, wherein the reservoir is made of aluminum and comprises a metal spool for receiving metal.

4. The additive manufacturing system according to claim 1, further comprising an induction heater configured around the reservoir for melting the metal in the reservoir.

5. The additive manufacturing system according to claim 1, wherein the transducer is either a magnetostrictive transducer or a piezoelectric transducer.

6. The additive manufacturing system according to claim 1, wherein the transducer is electrically configured with a voltage source that receives input voltage pulses to facilitate the mechanical jerking of the piston.

7. The additive manufacturing system according to claim 1, comprising a polymer extruder configured to extrude a polymer onto the CNC bed through a second nozzle functionally configured with the CNC bed for the purpose of manufacturing an object, and configured to move relative to the CNC bed and the metal distribution mechanism.

8. The additive manufacturing system according to claim 7, wherein the polymer extruder is configured with a polymer spool for receiving the polymer.

9. The additive manufacturing system according to claim 7, comprising a controller operably combined with the CNC bed, the metal distribution mechanism, and the polymer extruder, and a control unit configured to control the relative motion between the CNC bed, the metal distribution mechanism, and the polymer extruder, and to control a series of operations of the CNC bed, the metal distribution mechanism, and the polymer extruder.

10. The additive manufacturing system according to claim 7, wherein the object is manufactured by a series of steps: extruding a polymer from the polymer extruder and distributing molten metal from the metal distribution mechanism.

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