Systems and methods for using direct ink writing to make a 3D electromagnet

Abstract

A system for direct ink write printing an elongated conductive element. The system may involve a controller and a print nozzle configured to extrude first and second materials. The first material may be an electrically conductive material, and the second material may be an electrical insulator. A motion control subsystem is in communication with the controller for controlling movement of the print nozzle system along a non-linear pattern in X, Y and Z axes, in a manner to encase a bead of the first material fully within the second material, to thus form the elongated conductive element.

Description

SYSTEMS AND METHODS FOR USING DIRECT INK WRITING TO MAKE A 3D ELECTROMAGNETCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a PCT International Application of United States Patent Application No. 18 / 478,523, filed on September 29, 2023. The disclosure of the above application is incorporated herein by reference.FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] This invention was made with Government support under Contract No. DE-AC52-07NA27344 awarded by the United States Department of Energy. The Government has certain rights in the invention.FIELD

[0003] The present disclosure relates to systems and methods for direct ink write, additive manufacturing printing, and more particularly to systems and methods for direct ink write printing of an electrically conductive 3D wire well suited for use with electromagnets and other electromagnetic components.BACKGROUND

[0004] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

[0005] Additive manufacturing (“AM”) systems and methods continue to grow in interest and popularity. AM systems involve a variety of different approaches including selective laser sintering (“SLS”), laser based powder bed fusion (“LBPBF”), and Direct Ink Write (“DIW”), just to name a few.

[0006] Up until the present time, however, there has been a dearth of work exploring the possibility of using AM systems and methods for 3D printing superconducting materials and geometries. In particular, a DIW AM system provides significant flexibility in printing complex geometries, although up until the present time, very little work has been done with exploring the possibility of using a DIW AM system to create superconducting materials and geometries.

[0007] It should also be appreciated that a number of technological areas utilize a wide variety of different magnets configurations, such as magnetic traps, fusion system magnets and accelerator focusing optics. Many of these devices require magnets built in unique shapes and sizes that are difficult to wind and assemble, and which provide a basis for other engineering requirements, such as cooling, stress management, and quench protection. In various applications involving lasers, the availability of custom magnets with precisely located windings would be an invaluable support to programmatic work, chiefly by reducing higher multipole moments that can affect beam quality in accelerators.

[0008] With specific reference to electromagnets, these components have been used for centuries for research and commercial applications. These devices are generally created by wrapping an insulated wire for multiple turns in a specific geometry to produce a desired magnetic field. Over time, the shapes of these coils have been diversified and can now be extremely complex. The winding of the coil may present difficulties and require extensive fixturing and precise wire placement to create a magnetic field without perturbations. Additive manufacturing holds promise in this field as a disruptive technology that is rapidly advancing and becoming ubiquitous in the scientific community. Additively- manufactured, or 3D-printed, parts are used in state-of- the-art facilities around the world, and the printing of multiple materials simultaneously is now possible to 10-micron precision. Combining this technique with a device nearly two centuries old promises significant contributions in several key fields, including accelerators, magnetic traps, and energy.

[0009] The ability to form a superconducting material in an arbitrary geometry, made possible by DIW AM printing, would also allow for significantly more flexible use of superconducting materials, and potentially open up such materials to parts and applications which heretofore would not have been possible. In particular, the use of a DIW AM printing system with superconducting materials, if successful, could lead to the elimination of strain degradation in a conductor. This is because the strain degradation experienced by a super conductor would typically otherwise hamper the magnitude of current a superconductor can carry by placing the native conductor in is geometry prior to being fired and formed into its superconducting state.

[0010] The ability to DIW AM print superconducting materials would also allow for cooling channels and stress management to be placed near the superconductor allowing for higher performance.

[0011] Accordingly, there exists a need for developing DIW systems and methods which are able to be used to print parts and components having widely varying sizes and geometries using superconducting materials.SUMMARY

[0012] This section provides a general summary of the disclosure and is not a comprehensive disclosure of its full scope or all of its features.

[0013] In one aspect the present disclosure relates to a system for direct ink write printing an elongated conductive element. The system may comprise a controller and a print nozzle system. The print nozzle system may be configured to extrude first and second materials, the first material being electrically conductive and the second material being an electrical insulator. A motion control subsystem may be included which is in communication with the controller for controlling movement of the print nozzle system along a non-linear pattern in X, Y and Z axes, in a manner to encase a bead of the first material fully within the second material, to form the elongated element.

[0014] In another aspect of the present disclosure the motion control subsystem is configured to control movement of the print nozzle system to follow a helical pattern.

[0015] In another aspect of the present disclosure the print nozzle system is further configured to extrude a third material to encase the second material, the third material forming a structural material to at least one of protect or add a quantity of rigidity to the elongated conductive element.

[0016] In another aspect of the present disclosure the print nozzle system comprises a print nozzle configured to co-extrude the first and second materials simultaneously.

[0017] In another aspect of the present disclosure the print nozzle system comprises a first print nozzle configured to extrude the first and second material from independent first and second print nozzles.

[0018] In another aspect of the present disclosure the first material comprises silver.

[0019] In another aspect of the present disclosure the second material comprises alumina.

[0020] In another aspect of the present disclosure the print nozzle system is configured to extrude a third material over the second material to fully encase the second material, and wherein the third material comprises copper.

[0021] In another aspect of the present disclosure the elongated conductive element comprises an electrically conductive wire.

[0022] In another aspect of the present disclosure the elongated conductive element is formed in a helical configuration to circumscribe a cylindrical magnet.

[0023] In another aspect the present disclosure relates to a system for direct ink write printing on an electrically conductive wire. The system may comprise a controller and a print nozzle system for extruding first, second and third materials. The first material is an electrically conductive material, and the second material is an electrical insulator. A motion control subsystem may be included which is in communication with the controller and configured to control movement of the print nozzle system along sequential helical patterns in X, Y and Z axes, in a manner to encase a bead of the first material fully within the second material, and to encase the second material fully within the third material, to form the electrically conductive wire.

[0024] In another aspect of the present disclosure the first material comprises silver.

[0025] In another aspect of the present disclosure the second material comprises alumina.

[0026] In another aspect of the present disclosure the third material comprises copper.

[0027] In another aspect of the present disclosure the print nozzle system is configured to extrude a fourth material to encase the third material and to add at least one of strength or rigidity to the electrically conductive wire.

[0028] In another aspect of the present disclosure the print nozzle is configured to co-extrude the first, second and third materials at least one of simultaneously or sequentially.

[0029] In still another aspect the present disclosure relates to a method for printing an elongated, conductive, three-dimensional element. The method may comprise providing a controller. The method may further include using a print nozzle system to extrude first and second materials, with the first material being electrically conductive and the second material being an electrical insulator. The method may further include using a motion control subsystem in communication with the controller andconfigured to control movement of the print nozzle system along a non-linear pattern in X, Y and Z axes, in a manner to encase a bead of the first material fully within the second material, to form the electrically conductive, three-dimensional element.

[0030] In another aspect of the present disclosure the non-linear pattern comprises a helical pattern.

[0031] In another aspect of the present disclosure using a print nozzle system comprises using a print nozzle configured to co-extrude the first and second materials.

[0032] In another aspect of the present disclosure using the print nozzle system comprises using the print nozzle system to extrude a third material in a manner to fully encase the second material, to provide at least one of strength or rigidity to the elongated, electrically conductive, three-dimensional element.

[0033] Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations and are not intended to limit the scope of the present disclosure.

[0035] Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.

[0036] Figure 1 is a high level block diagram of one example of a DIW system that may be used to simultaneously print a plurality of materials to form a 3D wire;

[0037] Figure 2 is a partial side cross sectional view of a nozzle configured to extrude three inks simultaneously;

[0038] Figure 3 is a series of images illustrating a staircase method of printing a wire in accordance with the present disclosure;

[0039] Figure 4 is a highly magnified image of a cross section of silver printed in plastic using the staircase fabrication technique of Figure 3;

[0040] Figures 5a-5c show images of the alumina boats that were created and a cross section after baking (Figure 5b and highly enlarged in Figure 5c);

[0041] Figures 6a-6d show a highly enlarged image of an alumina boat sample baked at 925 C; Figure 6b shows a close-up image of the floating silver wire indicatingthe wire is metallic in nature and solid, yet porous; Figure 6c shows a further close-up of the silver showing a honeycomb or neural network pattern of the silver; Figure 6d shows a scanning electron microscope image taken that shows the optical image is a false image; the SEM only picked up silver and no indication of another material located between the silver network;

[0042] Figures 7a-7c show images of silver fully enclosed in alumina using the staircase printing method;

[0043] Figures 8a-8e show a cross section of a triaxial extruded wire comprised of silver, alumina and copper; Figure 8b shows a close-up image of the post baked silver with a semi translucent material in the matrix of the silver; Figure 8c shows a post backed wire cracked open; Figure 8d shows the delaminating copper on the exterior of the wire; and Figure 8e shows the black pockets in the alumina;

[0044] Figures 9a-9c show three different configurations of wire used in studies conducted pursuant to the present disclosure, and how they are affected by the vacuum bake at 4 hours;

[0045] Figures 10a-10c show the silver cores of the three geometries, with Figure 10a from a coaxial design created in a vacuum environment; Figure 10b shows a core from a triaxial design created in an environment with Argon, and Figure 10c shows a core from a staircase design created in an environment with Argon;

[0046] Figure 1 1 is a highly magnified image of a coaxial sire showing that copper or another material is located within the core;

[0047] Figure 12 show graphs of differential scanning calorimeter (DSC) measurements to illustrate at what points during the temperature profile the binder in the material are breaking down, as well as the onset, and peak, for the sintering process on a triaxial wire;

[0048] Figures 13a-13h show one example of various steps that may be performed in manufacturing a solenoid coil; and

[0049] Figure 14 is a high level flowchart showing one example for constructing a coil in accordance with the present disclosure.DETAILED DESCRIPTION

[0050] Example embodiments will now be described more fully with reference to the accompanying drawings.

[0051] The present disclose is directed to systems, components and methods for producing a 3D electromagnet using a direct ink writing (DIW) AM approach. A principal focus of the present disclosure is using a 3D AM system and method to 3D print at least three different materials: 1 ) copper, which has excellent structural rigidity; 2) alumina, which has excellent electrical insulation; and 3) silver, which has excellent conduction properties. These three materials in particular are focused on in the present disclosure and have been tested after being printed and after being sintered. However, the present disclosure is not limited to use with only these three materials. For example, in place of silver, other materials such as copper, gold, MgB2, 2212, or a filamented matrix of composite materials, may be used. For the insulator, in place of alumina, for example, other materials such as alumina, zirconia, silica, magnesia and porcelain. In place of copper, for example, materials such as stainless steel, brass, nickel, chromium, molybdenum, iron, and alloys of any of the previously listed materials may be used.

[0052] In one instance using a commercial co-extrusion nozzle with a DIW AM printing system, the three materials were extruded as a wire consisting of a silver conductor coated with alumina insulation and sheathed in copper. The wire was tested for conductivity and post-sintering properties. This procedure was repeated to determine optimal baking procedures for achieving the highest conductivity and most reliable conductor. The materials integrated well. The process culminated in producing an insulating wire composed of the three above-mentioned materials, which was conducting along its axial center, and insulating from the silver inner core to the copper outer sheath.

[0053] Before proceeding further with a specific discussion of the results of the obtained DIW AM printing results, a brief discussion will be presented as to one example of a DIW additive manufacturing system 10 that may be used in 3D printing a 3D electromagnet in accordance with the present disclosure. The system 10 is but one example, and those skilled in the art will appreciate that a wide range of variations may be made to the system 10 shown in Figure 1 , and that the present disclosure is not limited to any specific form of DIW AM printing system.

[0054] The DIW system 10 in this example makes use of a (“DIW”) system in which a flowable feedstock, in this instance a flowable (e.g., ink, powder, slurry, etc.) copper contained in a reservoir 16a, alumina contained in a reservoir 16b, and silver contained in a reservoir 16c, are supplied through a valve 18 (e.g., electronically control valve) to a print nozzle 20 from which each of the copper, alumina and silver feedstock are co-extruded. However, it will be appreciated immediately that the present disclosureis not limited to co-extrusion of the above-mentioned materials, and more or more independent and printing operations could be performed to print the above-mentioned materials in two of more sequential operations (i.e., not co-extrusion printing). Also, two or more separate printing nozzles could just as well be used rather than a single nozzle that co-extrudes ass the three above-mentioned materials.

[0055] The copper, alumina and silver in this example, however, are coextruded as a bead 22 having a desired cross sectional shape, depending on the configuration of the tip of nozzle 20, onto a build plate 24. The nozzle 20 may be controlled for highly precise movement within the X, Y and Z axes by a motion control subsystem 26 comprised of one or more DC stepper motors, linear actuators or other suitable components. The motion control subsystem 26 may be controlled by control signals from a computer / electronic controller 28 (hereinafter simply “controller” 28) or optionally by an external controller (not shown). Optionally, build plate 24 may be operatively coupled to a motion control stage 30 (e.g., including one or more DC stepper motors, linear actuators or other suitable components), which is in turn controlled by signals from an external controller or optionally by the controller 28.

[0056] In one example the print nozzle 20 is a 5-axis print nozzle, and the flow of the copper, silver and alumina feedstocks may be controlled by use of the flow control valve 18, in one implementation via received electronic flow control signals from an electronic controller 28, to regulate the rate of the copper, silver and alumina feedstocks to the print nozzle 20 as needed to construct a specific component. To assist in this, the controller 28 may include a memory 30 (e.g., volatile and non-volatile RAM / ROM / DRAM, etc.) for storing a 3D part design file 32. A separate G-code generating module 34 may also be stored for generating module may also be included for designing and creating the toolpaths needed to form one or more specific components. The final printed component is multi-layer, 3D arrangement of these toolpaths generated from G-code, controlling the print nozzle 20, where the toolpaths have been sourced from a stored toolpath planning and design algorithm.

[0057] The feedstock 16 (with one or both of the chopped / milled fibers 24 or continuous fiber 22) may be extruded from the printing nozzle component 12 and used to form each layer of a component or part, in a layer-by-layer process, starting with an initial layer deposited on a sacrificial support material 24a. Optionally, one or more ultraviolet (“UV”) lights 25 may be used to project UV light onto the just-deposited feedstock 16 to UV cure the feedstock virtually immediately after it is laid down. The UVlight 25 may be secured or slaved to the nozzle component 12 so as to move with the nozzle component 12. Alternatively, the UV light 25 may be stationary with a beam sufficient to illuminate the entire build plate 20a at once.

[0058] With brief reference to Figure 2, a partial cross sectional view of the print nozzle 20 is shown. The print nozzle 20 in this example has three coaxially arranged flow paths 20a, 20b and 20c. Flow path 20a is longitudinally along an axial center of the print nozzle 20 and in this example supplies the silver feedstock. Flow path 20b supplies the alumina feedstock, and flow path 20c supplies the copper feedstock. The three feedstocks in this example form the bead 22. It will be appreciated that the relative cross- sectional dimensions of the flow paths 20a-20c may be selected based on the desired 3D construction of the component being printed. For example, while the cross-sectional thickness of the flow path 20c is shown only slightly larger than the flow path 20b, instead the flow path 20c may be constructed with a significantly larger or smaller cross sectional thickness relative to the flow path 20b. Similarly, the diameter of the flow path 20a may be varied as needed relative to both of flow paths 20b and 20c to impart any desired performance / conductance characteristic for the finished DIW AM printed component. And still further, while the flow paths 20b and 20c are show as fully radially circumferential flow paths extending through the print nozzle 20, it will be appreciated that in some instances one or both of flow paths 20b and / or 20c may be only partial circumferential flow paths which extend fully longitudinally through the nozzle 20 to a tip of the nozzle. As such, the illustration of Figure 2 should be understood to represent just one example of an embodiment of the nozzle 20, and particularly an embodiment which is suitable for 3D printing a conductive in the form of an electromagnetic coil.

[0059] With the present disclosure, a DIW 3D printed, insulated wire was constructed. In this example each feedstock ink (i.e., each of the copper, alumina and silver feedstocks) is composed of a material and a buffer, and has the consistency of clay, and furthermore is self- supporting when printed. When baked, the printed feedstock material becomes a fully dense solid. The feedstock materials, those being copper, alumina and silver, were printed (i.e., co-extruded) using the DIW system 10. The copper provides a rigid structure, while the insulator alumina encloses the conductive silver core. In one instance coaxial extrusion of all three materials was performed simultaneously. In a second instance a “staircase” printing method was performed where a single nozzle printed a single one of the three feedstock materials, and severaladditional nozzles were used to print the entire structure in layers, one at a time, and all material in a given single layer, one layer at a time.

[0060] The present disclosure involved DIW AM printing tests using a “staircase” type of layer-by-layer printing sequence. Briefly, such a sequence is shown in Figure 3 with printing steps 1 through 8, using three different materials A, B and C, to fully encapsulate material C. Material C may be a conductor.

[0061] Open boat geometries, such as shown in Figure 4, were also printed to allow easy examination of the printed wire. Figure 4 shows a cross-sectional view of a component 50 where silver 52 was printed in plastic 54 using the staircase fabrication technique mentioned above. This showed that the staircase design of Figure 3 is a viable method for DIW AM printing an electrically conductive component. Further DIW AM printed sample component wires were capped with plastic making them completely enclosed, creating an insulated silver wire.

[0062] In these tests silver was used as the inner conductive core of the wire because of previous experience with DIW AM printing silver as the ink. When printed in the plastic insulation, however, the conductivity was found to be approximately 100 times less conductive than pure silver. The samples were examined under a Scanning Electron Microscope (SEM), and based upon the SEM work, the silver particulates were found to be not particularly well connected. This observation led to a belief that baking the conductor may be required, as well as the idea of using alumina as an insulator. In particular, alumina is well known to be a good insulator and able to withstand the high temperature baking needed to achieve sintering.

[0063] During one test using a commercial co-extrusion point nozzle, the three materials were extruded as a wire consisting of a silver conductor coated with alumina insulation and sheathed in a copper. The wire was tested for conductivity and postsintering properties. This procedure was repeated to determine optimal baking procedures for achieving highest the conductivity and most reliable conductor. The materials were expected to integrate well, based on experience, but this turned out to be a not trivial process. The work culminated in producing an insulating wire composed of three different materials that was axial conducting longitudinally along its axial silver inner core, and insulating from the silver inner core to the copper outer sheath.

[0064] Alumina boats were created and sintered at various temperatures. Prior research indicated that 1400QC would allow the alumina to sinter to nearly full density. This temperature was also advantageous as Stainless Steel also sinters close to thistemperature, which was believed to potentially be a viable route for a stiff structural material. Investigative work with the SEM and Electron Backscatter Diffraction (EBSD) showed that the alumina surface had few cracks and was more uniform with a 1200QC bake compared to the 1400QC bake. Additionally, the stoichiometry indicated that the 1200QC was close to pure alumina while 1400QC had 4% higher oxygen content in comparison. Silver is relatively inert in oxygen, so it can be baked as well. Previous research has shown that silver does oxidize at elevated temperature near 800QC, but only the outer few angstroms of its surface thickness.

[0065] New samples were then made with silver added in the alumina boat trough. These samples were baked at 1200QC in argon. This is shown in Figures 5a-5c which show the topology of the alumina boats and the cross section after baking. Figure 5b shows a measured cross-section of the boat. This was consistent along the length and across multiple samples. A variation of 12% across the samples was seen. In particular, Figure 5c shows a close up image of an alumina boat 60 after bake. Small spheres 62 of silver can be seen and are dimensioned to indicate the sizes of the balls that filled the channel. The red discoloration 64 appears to be Alumina with small amounts of silver by EBSD. The result, shown in Figures 5a, 5b, 6a, 6b, 6c and 6d, was that the silver, when elevated above its melt point, did not create uniform filament as anticipated. Rather the surface tension of the silver caused the formation of small spheres of silver that then fell out of the boat under any mechanical perturbation. The resulting pores 60 are visible in Figures 5c, 6b, 6c and 6d. This same process was repeated with a completely enclosed silver filament in alumina. After the bake, the sample was broken transversely, and small spheres could be poured out of each half of the sample. As a result, the future bakes had to be performed below 962QC, the melting point of silver.

[0066] Figure 5a shows the profile of the alumina channel post bake. Over 10 samples were made, with length variation of + / -12% over all samples. This includes with and without the silver filament included in the boat. The center trough in the alumina was also consistent in its depth at around 0.5 mm.

[0067] An alumina boat with silver inlay was printed and baked at 925QC. The result was even better than anticipated. The alumina was uniform and did not exhibit cracking. The silver was most importantly a single piece that was malleable, conductive, and fairly robust. A strand was inspected as shown in Figures 6a-6d. Upon closer inspection it can be seen that the individual particulates merged into a neural network, orhoneycomb structure, that is well connected. The conductivity of the silver was approximately 10 times less conductive than pure silver. Note that due to the porous nature of the silver, the losses should be even higher, but conductivity is still is 10 times better than un-sintered silver. Specifically, Figure 6a shows an image of an alumina boat sample baked at 925QC. The sample was cracked for to perform a cross sectional image and the silver peeled off intact. The wire was durable, malleable, and conductive. Figure 6b show a highly enlarged, close-up image of the floating silver wire 66 indicating the wire is metallic in nature and solid, yet porous. Figure 6c shows a further close-up of the silver revealing a honeycomb or neural network pattern of the silver. The images appear to show a translucent gel or solid between the silver connections. Figure 6d shows an SEM image that reveals that the optical image is a false image. The SEM only picked up silver and no indication of another material located between the silver network.

[0068] Samples of silver completely enclosed in alumina were made using the staircase method. Additionally, coaxially extruded wires comprised of alumina and silver were made using a commercial nozzle. These samples were baked and found to have similar properties to the boats. During the examination of these samples, a dark discoloration was seen in the bulk alumina in both the staircase printed method and the coaxial printed method. The cross section of the sample is shown in Figure 7. This discoloration was found to likely be carbon from SEM results. The white outer layer is free of the contamination, which suggested that the carbon was able to escape through the outer layers but trapped in the bulk material. Up to 30% of the material in that section was carbon.

[0069] Another interesting finding was that there was an absence of oxygen though out the sample. It is likely that there are two possible reasons for this result. The first is that the oxygen is being pulled up with the buffer via chemical process. The second potential cause is the SEM itself. The narrow spot size combined with an uneven surface possibly contributed to the error. Additionally, the oxygen content could be altered for some analyses to fit a normal alumina distribution in some sample by turning carbon on / off during the spectral analysis.

[0070] Upon examination of the coaxial extruded wires it was found that the extrusions were hollow, which is surprising based upon the method of fabrication. When using a standard coaxial nozzle, this should have produced a single solid core. This hollow feature persisted in all samples prior to baking and after.

[0071] A triaxial extrusion was then executed to prove that a truly insulated wire could be made. A conductive inner core and conductive outer jacket were used to allow for a simple assessment of resistance from the inner core to the outer core. An image of the un-sintered triaxial extruded wire pre- and post- bake is shown in Figures 8a-8d. A wire 80 was fired at 925QC in an inert atmosphere. The most noticeable result was the bulk of the copper delaminating from the surface of the wire. A thin layer of copper adhered to the surface of the alumina, but the majority of the material was loosely connected and fell off with a light to moderate touch. This was likely due to the mismatched contraction of the various materials. During the alumina boat phase of the project, a set of cubes were fabricated and measured prior to bake and post bake. The contraction of the different materials was examined and showed that the copper shrunk 17% more than the alumina by volume. Hence, the copper splitting and delaminating is consistent with the data. Similarly, the silver contracted 13% percent more by volume compared to the alumina. This is consistent with thickness of the silver pre and post bake of the triaxial silver core thickness reduction. The average thickness of the silver post bake was reduced by approximately 40% which is consistent with the values above.

[0072] With specific regard to the figures, Figure 8a shows a cross section of the triaxial extruded wire 80 comprised of silver, alumina, and copper. The origin of the center whole is the portion under investigation. Figure 8b is a highly enlarged close-up image of the post baked silver. A semi translucent material is in the matrix of the silver. An extended bake is being further investigated. Figure 8c shows a post backed wire cracked open. The silver is conductive, but an order of less than the silver core alumina samples. The carbon concentration is similar to previous experiments. Figure 8d shows the delaminating copper on the exterior of the wire. Figure 8e highlights the black pockets 82in the alumina.

[0073] The triaxial wires were also checked for shorts. The straight pieces all had near 20 MO of resistance between the silver core and copper jacket. However, a curved piece of the triaxial wire was tested and had 18 kO of resistance. Thus, it is believed that somewhere in the print the insulation had become thin, such that current could pass through the insulating layer.

[0074] The straight sections of wire had very little resistance, roughly ~ 0.5Q. Several pieces were tested and received similar values for similar lengths. The triaxial extruded wire appeared to have buffer still within the silver matrix after the 4 hour bake.This resulted in a loss of conductivity of about an order of magnitude of the enclosed samples.

[0075] In an attempt to reduce the black / carbon content of within the wire, the samples were put through a vacuum bake. The pressure was kept at a few torr and the sample was baked for 4 hours similar to the previous samples. A second set was placed in an argon environment and baked for 24 hours, 6 times longer than previous samples.

[0076] The vacuum samples showed no signs of black contamination in the alumina or elsewhere for all three samples: coaxial drawn, staircase sample, and triaxial wire. This illustrates that, with a minimum vacuum, the contamination was dramatically reduced. In addition, the density of the silver appeared to have increased as well. Figures 9a-9c show the lack of carbonization in all three configurations. Figures 10a-10c show the silver cores of the three geometries. In the vacuum (Figure 10a, 4 hours) and 24 hour in Argon cases (Figures 10b and 10c).

[0077] The cores appear more dense and crystalline in nature compared to the more dendrite or neural network core in Figures 6 and 9a-9c. The core on the left is from the coaxial design and was extremely tough to cut but still malleable. The other two, triaxial and staircase, cut much easier but were as well malleable and durable.

[0078] The 24 hour baked samples also had significantly reduced carbonization. In the coaxial and triaxial the discoloration was absent. However, in the thicker walled staircase printing method, a darker area was located near the inner core, as visible in Figures 7a, 7b, and 7c. This was to a significantly lesser degree than previous samples.

[0079] In all cases where the copper outer jacket was used, the copper was blackened substantially. The copper was still delaminated from the alumina due to the contraction differential. The major changes were that it was not nearly as fragile in both cases and had a darker coloration than the previous samples. The cause is unknown, but oxidation may be a key contributor.

[0080] One of the more dramatic changes beyond removal of the blackening in the alumina was the silver cores. The density in the cores appears to be increased dramatically. Figures 10a-10c show the cores of the wires and how the neural network no longer appears, but rather there exists a solid crystalized material. The triaxial and the staircase silver cores were durable and flexible when removed from their alumina casings. The coaxial silver core was flexible and significantly stronger than the other samples. The material was so tough that a pair of shears was unable to cut the wire.Upon closer inspection it appears the silver used for the coaxial core is alloyed with another substance that is copper in color as shown in Figure 1 1. This warrants further investigation as the durability and connectivity appear to be high.

[0081] Impedance measurements were made on the new set of wires. The one of most interest was the coaxial line that had the impurities and was very tough. An impedance device was used that allowed varying level of current to check the resistance. The use of an impedance analyzer was attempted but the background resistance was higher than the value measured. The 26.5 mm long, 1.5 mm diameter wire was measured to have a resistance of 1 .02 mO. The conductance is therefore 1 .44E7 S / m compared to the value of pure silver 6.3E7 S / m. This factor of 4.3 is a substantial improvement from the factor of 100 initially achieving from the first sample.

[0082] To understand how the wires are acting and where physical and chemical transitions are occurring, a triaxial sample was measured using DSC / TGA analysis. Figure 12 shows the endothermic and exothermic peaks resulting from the binder decomposing and sintering. There are 4 exothermic peaks that are occurring. Note the background gas was argon, so the mass loss is from binders evolving and no endothermic or exothermic gases are present by design. The first three exothermic peaks occur at 160 C, 325 C, and 410 C. It is our belief that this corresponds to the three different materials removing their binders as the mass loss increases at each of these temperatures. The fourth large peak is attributed to the material sintering reflected by the minimal weight loss. When the dwell occurs the peak quickly drops to zero.

[0083] The present disclosure thus discloses various methods to create 3D printed wires using different techniques. There were several complications that were encountered, as noted above, but these have been addressed. The issues of contamination, connectivity, manufacturability, and materials have been addressed. Further areas of interest for future work may involve adjustment of the materials for contraction and to even better ensure the outer structural layer is rigid.

[0084] The development of the wires discussed herein shows that additively manufactured wires are producible using two different methods. Both the coaxial and staircase methods were able to produce conductivities 10 times less than pure silver, which is still very acceptable for many applications. The triaxial wire shows that structures can be printed that are able to insulate between the core and outer conductor. The work described herein also demonstrates that curved pieces and serpentine shapes have been created in a print. This provides the first concrete work which enables printingelectromagnets in various configurations. This is further expected to support the accelerator work performed at Lawrence Livermore National Laboratory.

[0085] An example of an electromagnet printed using the staircase printed method is shown in Figures 13a-13h to form a solenoid. The inner surface of the magnet will be comprised of steel structure 100, as shown in Figure 13a. Consecutive layers are built up as shown in Figures 13b-13h until the inner layer of the dielectric is reached (Figure 13b). So in this example, Figure 13b involves printing an additional material 102 which may have a specific desired magnetic property. Figure 13c shows next printing an insulator material 104 over the material 102. Figure 13d shows printing a steel or ferrite layer 106 to give further added strength and rigidity. Figure 13e shows printing a layer of gold 108. Figure 13f shows a layer 110 of steel to make the side walls higher, further building on 106. Figure 13g shows a layer 1 12 of insulation printed over layer 108 or sealing the gold wire in an insulating case. Figure 13h shows a structural element 1 14 printed over layer all elements to better hold the entire assembly in place. In performing the operations shown in Figures 13a-13h, the printhead may follow a helical pattern down the axis, and once complete, returns back to its initial position and fills in the structural material. This same process occurs when the conductor is reached. The conductor layer is printed first, then the dielectric, followed by the filling of the structure. This continues until the outer surface of the wire is reached. The process continues in this manner until the magnet structure is complete. This process is for a solenoid but similar wires can be made for dipoles, quadrapoles, canted coils, etc.

[0086] Figure 14 shows a high level flowchart 200 representing one example of various high level operations that may be performed to construct a solenoid in accordance with the present disclosure. At operation 200 an inner steel magnet core of desired dimensions is initially provided. At operation 202 the inner layer of dielectric (in a helical pattern) may then be printed. At operation 204 a structural material to provide rigidity to the coil portion of the solenoid may then be printed (using a helical pattern). At operation 206 a conductor material may be printed (using a helical pattern). At operation 208 a dielectric may be printed (using a helical pattern). And finally at operation 210 a structural material, for example forming a layer enclosing all of the previously printed materials, may be printed. Finally, at operation 212, the component may be baked for a predetermined time at a predetermined temperature.

[0087] It will be appreciated that Figure 14 represents various operations for just one example of how a coil portion of a solenoid may be formed. Some of theoperations explained above may modified and some may potentially be eliminated, depending the exact shape or configuration of the part being printed. The three materials discussed in this example may be printed using repeated helical print head tool paths to construct the desired part or structure. In this example the part will be a wire which when finished will be in a helical pattern. In some operations it may be desirable to print the finished part first, using a mandrel as the inner component in place of the inner steel magnet core. Both implementations are envisioned by the present disclosure.

[0088] Applications of this technology, if successful in converting the wires onto specified forms such as the solenoid magnets, are abundant. Stockpile science can benefit from this work by capitalizing on the new technology to enable superior Linear Induction Accelerators through the more sophisticated optics generated by the magnet. Engineering designs can become more efficient and simplified, with constraints for insulation, cooling, manufacturing, and wire winding relaxed. Components for nuclear- threat reduction via neutron sources, energy, and diagnostic equipment may also be improved.

[0089] The present disclosure illustrates that wires can be fabricated that have satisfactory conductivity and insulating properties. The development of the two separate methods provides flexibility in the future and opens the trade space for still greater future development of conductor technology, wire fabrication technology, and magnet fabrication.

[0090] It will also be appreciated that the systems and methods described herein are not necessarily limited to the various specific materials mentioned herein. Other materials may potentially be used, although the specific materials mentioned herein are materials that would be particularly easy and useful to implement. For example, one other material that may be fairly easy to implement is NbTi for the inner conductor. Accordingly, the systems and methods described herein are not limited to any set of materials, but rather any material that is able to be printed, and which has the desired electrical properties, may potentially be used.

[0091] Any future research is expected to likely focus on three particular areas of interest: conductor, wire, and magnet fabrication. Of particular interest is the exploration of alternate conductors that have high potential but are hindered by strain degradation during manipulation for end fabrication in a complex multipole accelerator quality magnet.

[0092] The present disclosure uses the additive manufacturing technique of direct ink writing to create superconducting materials and geometries. The ability to put a superconducting material in an arbitrary geometry allows for more flexible use and heighten usage. Using the direct ink method can potentially lead to the elimination of strain degradation in a conductor that can hamper the current a superconductor can carry by placing the native conductor in is geometry prior to being fired and formed into its superconducting state. This technique is expected to also allow for cooling channels and stress management to be placed near the superconductor, allowing for even higher performance.

[0093] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

[0094] Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

[0095] The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. The method steps, processes, andoperations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.

[0096] When an element or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0097] Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

[0098] Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

Claims

AMENDED CLAIMS received by the International Bureau on 05 March 2025 (05.03.2025)What is claimed is:

1. A system for direct ink write printing an elongated conductive element, comprising: a controller; a print nozzle system for co-extruding first, second, and third materials, the first material being electrically conductive and being flowed through a central axial flow path of the print nozzle system, the second material being an electrical insulator, and the third material being a material to impart structural rigidity to the elongated conductive element; and a motion control subsystem in communication with the controller for controlling movement of the print nozzle system along a non-linear pattern in X, Y and Z axes, in a manner to encase a bead of the first material fully within the second material, and to encase at least a portion of the second material within the third material, to form the elongated conductive element.

2. The system of claim 1 , wherein the motion control subsystem is configured to control movement of the print nozzle system to follow a helical pattern.

3. The system of claim 1 , wherein the print nozzle system is further configured to extrude the third material to fully encase the second material, the third material forming a structural material to at least one of protect or add a quantity of rigidity to the elongated conductive element.

4. The system of claim 1 , wherein the print nozzle system comprises a print nozzle configured to co-extrude the first and second materials simultaneously.

5. The system of claim 1 , wherein the first material comprises silver.

6. The system of claim 5, wherein the second material comprises alumina.

7. The system of claim 1 , wherein the print nozzle system is configured to extrude the third material over the second material to fully encase the second material, and wherein the third material comprises copper.

8. The system of claim 1 , wherein the elongated conductive element comprises an electrically conductive wire.

9. The system of claim 1 , wherein the elongated conductive element is formed in a helical configuration to circumscribe a cylindrical magnet.

10. A system for direct ink write printing an electrically conductive wire, comprising: a controller; a print nozzle system for extruding first, second and third materials; the first material being an electrically conductive material, the second material being an electrical insulator; and a motion control subsystem in communication with the controller and configured to control movement of the print nozzle system along sequential helical patterns in X, Y and Z axes, in a manner to encase a bead of the first material fully within the second material, and to encase the second material fully within the third material, to form the electrically conductive wire.

11. The system of claim 10, wherein the first material comprises silver.

12. The system of claim 10, wherein the second material comprises alumina.

13. The system of claim 10, wherein the third material comprises copper.

14. The system of claim 10, wherein the print nozzle system is configured to extrude a fourth material to encase the third material and to add at least one of strength or rigidity to the electrically conductive wire.

15. The system of claim 10, wherein the print nozzle is configured to co-extrude the first, second and third materials at least one of simultaneously or sequentially.

16. A method for printing an elongated, conductive, three-dimensional element, comprising: providing a controller; using a print nozzle system to extrude first, second third materials, the first material being electrically conductive and extruded through an axial center flowpath of the print nozzle system, and the second material being an electrical insulator; and using a motion control subsystem in communication with the controller and configured to control movement of the print nozzle system along a non-linear pattern in X, Y and Z axes, in a manner to encase a bead of the first material fully within the second material, and to encase at least a portion of the second material within the third material, to form the elongated, electrically conductive, three-dimensional element.

17. The method of claim 16, wherein the non-linear pattern comprises a helical pattern.

18. The method of claim 17, further comprising using the print nozzle system to extrude the third material in a manner to fully encase the second material, to provide at least one of strength or rigidity to the elongated, electrically conductive, three- dimensional element.

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