Systems and methods of printing 3D lattices

Abstract

Systems and methods for printing lightweight lattices using coordinated multi-axis motion are disclosed. The lattices can be printed from silica glass filament. Strut members are printed by heating the filament with a laser and feeding the filament in at a constant angle, which allows for minimum deflection and increases printing speed. This takes advantage of molten glass viscosity and applies forces onto workpieces by the filament feeding or by the movement of the substrate relative to the feeder at the constant angle. Members can be connected at joints to form a group of struts, and multiple groups of struts can form a respective layer. A subsequent layer can be printed onto the top joints of the preceding layer's groups of struts. The filaments can be 2mm diameter borosilicate glass filaments. This can also be adapted to Alumina and ceramic filaments and even metals using laser or arc heating.

Description

SYSTEMS AND METHODS OF PRINTING 3D LATTICES STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0001] This invention was made with government support under grant FA8750-22-2-0501 awarded by the US Air Force Research Laboratory (AFRL). The government has certain rights in the invention.CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] The present application claims priority to and benefit of U.S. Provisional Application No.: 63 / 743,107, filed on January 8, 2025, and titled “METHOD OF PRINTING 3D LATTICES,” the entirety of which is herein incorporated by reference.TECHNICAL FIELD

[0003] This disclosure generally relates to systems and methods for 3D printing lattices made from glass, metals, or other materials.BACKGROUND

[0004] There has been a long desired, unsolved need to 3-dimensionally print glass lattices. Initial approaches involved using an up-down strategy following traditional digital glass forming approaches. Conventional lattice printing is layer by layer. This is slow and does not preserve the orientation. It is challenging to do with glass, which has advantages for strength to weight ratio and low coefficient of thermal expansion. However, because there is loading on the filament during deposition, it tends to distort and has geometric limitations. The setup in this disclosure has been reconfigured so that articulated 4-axis motion allows the filament to be fed at the printing angle without bending such that the members are always drawn up during printing. The present 3-dimensional (“3D”) printing method reduces the assembly of workpieces to printing of segments, short spot welds at joints, and breaking of the filament. This procedure has been demonstrated for 2 mm borosilicate glasses to print workpieces such as, for example, cubic lattices, although other shapes may be possible. The filament may be silica fiber, alumina rods, or other metals, according to various embodiments.

[0005] A non-limiting objective of the 3D printing method of this disclosure is to print large silica lattices in space. This addresses a need for lightweight, high accuracy, high stiffness, and low thermal expansion structures. In particular, it will enable the construction of structural elements in orbiting craft for precise relative positioning of critical space craftelements (e.g., large antenna arrays). Making the structural elements out of these types of filament is attractive because the loading in orbit is lower than during launch. Silica fiber, for example, has a higher stiffness to density ratio than titanium, in addition to a lower coefficient of thermal expansion and a grater maximum service temperature. In the absence of flaws, the tensile strength of silica fiber also significantly exceeds that of titanium.BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 is a flowchart illustrating an example method of 3D printing lattices.

[0007] Figure 2 is a flowchart illustrating an example method of 3D printing lattices using glass or other materials.

[0008] Figure 3 is a flowchart illustrating an example method of 3D printing lattices using glass or other materials.

[0009] Figure 4 is a front perspective illustrating an example system of a 3D print assembly.

[0010] Figure 5 illustrates a front perspective view of an example operation for 3D printing lattices according to coordinate systems.

[0011] Figure 6 illustrates a front perspective view of an example operation for 3D printing lattices.

[0012] Figure 7 illustrates a front perspective view of the example operation for 3D printing lattices.

[0013] Figures 8A-8B illustrate a front perspective view of the example operation for 3D printing lattices.

[0014] Figure 9 illustrates a front perspective view of the example operation for 3D printing lattices.

[0015] Figure 10 illustrates a front perspective view of the example operation for 3D printing lattices.

[0016] Figure 11 illustrates a front perspective view of the example operation for 3D printing lattices.

[0017] Figure 12 illustrates a front perspective view of the example operation for 3D printing lattices.

[0018] Figure 13 illustrates a front perspective view of the example operation for 3D printing lattices.

[0019] Figure 14 illustrates a front perspective view of the example operation for 3D printing lattices.

[0020] Figure 15 illustrates a front perspective view of an example operation for 3D printing lattices.

[0021] Figure 16 illustrates a front perspective view of an example operation for 3D printing lattices.DETAILED DESCRIPTION

[0022] This application discloses systems and methods related to an additive manufacturing technique termed digital glass forming (DGF), which can be utilized to print 3-dimensional (“3D”) structures. This technique involves feeding a filament of silica glass into the intersection of a laser and the workpiece. A CO2 laser is used as the energy source to heat the filament because it couples to the phonon mode in silica (although modifications to the glass can allow other lasers to be used). The laser heats the filament through excitation of the silica at the intersection, softening it so it can be plastically deformed locally by the forces exerted by the workpiece and the filament feeder. The filament is handled cold which allows force to be transmitted through the filament during the printing process. The printing process using silica glass filament differs from wire-fed metal processes because glass maintains significant viscosity when molten. The DGF process of this disclosure captures some of this flexibility, while adding the repeatability and precision of modern computer numerical control. Workpieces that can be formed from the DGF process of this disclosure include, for example and without limitation, fully dense lenses, functional fiber optics, capillary tubes, antenna arrays, and freestanding spirals.

[0023] In some non-limiting examples, the contents of this disclosure enable the 3D printing of functional lattice structures using standard optical fiber feedstock (SMF-28), although other types of glass filaments may be possible. Particular focus will be placed on how the process parameters affect the joints.

[0024] In some embodiments, a method of forming 3-dimensional (3D) workpieces using depositional printing includes aligning a filament feeder and laser at a global origin and preheating a filament; intersecting a substrate with a filament at a first location; moving the substrate while feeding the filament with the laser turned off; turning the laser back on to heat and breaking an end of the filament to define a first strut; rotating the substrate about a common center of intended group of struts by a first angle; and feeding filament to at least one additional location and depositing at least one additional strut to print the group of struts.

[0025] In some embodiments, feeding filament to the at least one additional location and depositing the at least one additional strut to print the group of struts includes feeding thefilament to a second location and depositing a second strut; rotating the substrate about the common center of struts by a second angle and feeding the filament to a third location and depositing a third strut; creating and centering a top joint of the group of struts; and creating at least one subsequent group of struts. In some embodiments, the second strut and the third strut are printed based on repeating the aligning, intersecting, moving, and breaking operations for depositing the first strut. In some embodiments, the at least one subsequent group of struts is printed based on repeating the operations for depositing the group of struts.

[0026] In some embodiments, creating the at least one subsequent group of struts includes creating a first layer of lattice from a plurality of group of struts; and creating at least one second layer of lattice on top of the first layer.

[0027] In some embodiments, a system includes a device configured to emit a light radiation beam having a certain wavelength; a feeder positioned relative to the device, the feeder configured to feed a non-metallic filament at a feed rate; a substrate having a surface for deposition of the non-metallic filament during a deposition process; and at least one sensor positioned to capture an image of an intersection of the filament and the light radiation beam. In some embodiments, the light radiation beam heats the non-metallic filament to a temperature to enable deposition of the non-metallic filament onto the substrate surface at a first angle to print a workpiece. In some embodiments, the substrate is translatable along at least one axis at a second rate to minimize forces on the non-metallic filament and to maintain the non-metallic filament at the first angle, the second rate being based on the feed rate.

[0028] In some embodiments, the device is a CO2 laser device configured to emit a focused light beam having a wavelength of 10.6 pm.

[0029] In some embodiments, the system further includes at least one mirror to coaxially heat the non-metallic filament with the light radiation beam during the deposition process.

[0030] In some embodiments, the non-metallic filament plastically deforms in response to one or more forces exerted onto the non-metallic filament when heated to the temperature.

[0031] In some embodiments, the non-metallic filament is handled cold. In some embodiments, the forces include a first force applied from feeding the non-metallic filament.

[0032] In some embodiments, the system further includes a controller and an assembly including the substrate and at least one motor to cause the substrate to move along the at least one axis. In some embodiments, the controller controls the at least one motor to translate the substrate along the at least one axis to maintain the non-metallic filament at the first angle during printing of the workpiece. In some embodiments, the controller controls the at leastone motor to translate the substrate along the at least one axis to apply at least one second force onto the non-metallic filament, the at least one second force configured to break the non-metallic filament from the printed workpiece.

[0033] In some embodiments, the feeder is rotatable about an axis to vary a density of the workpiece, wherein the controller controls the rotation of the feeder about the axis.

[0034] In some embodiments, the non-metallic filament includes silica fibers.

[0035] In some embodiments, the non-metallic filament is a borosilicate filament.

[0036] In some embodiments, a finished workpiece is a free-standing silica (SiO2) lattice structure having a lower density, a higher tensile strength, and a lower coefficient of thermal expansion compared to workpieces made of metallic filaments.

[0037] In some embodiments, the finished workpiece includes a plurality of free-standing members, each free-standing member being fused to at least one other free-standing member at a respective joint.

[0038] In some embodiments, an apparatus for printing 3D workpieces includes a device configured to heat a filament to a temperature; a filament feeder positioned relative to the device and configured to feed the filament at a first rate; a substrate having a surface for deposition of the filament during a deposition process, the substrate being translatable along at least one axis to maintain the filament at a certain angle during the deposition of the filament; and at least one sensor positioned to capture an image of the heating of the filament to the temperature and the deposition of the filament onto the surface during the deposition process. In some embodiments, the device heats the filament to a temperature to enable deposition of the filament onto the surface at the certain angle. In some embodiments, the substrate is translatable along the at least one axis at a second rate to minimize forces on the filament, the second rate being based on the first rate.

[0039] In some embodiments, the device is a CO2 laser device configured to emit light radiation beam having a wavelength of 10.6 pm.

[0040] In some embodiments, the filament is a silica glass filament. In some embodiments, a finished workpiece printed from the silica glass filament includes a 3D lattice structure having a lower density, a higher tensile strength, and a lower coefficient of thermal expansion compared to workpieces printed from metallic filaments.

[0041] In some embodiments, the filament is handled cold. In some embodiments, when heated to the temperature, the filament plastically deforms in response to a first force applied from feeding the filament. In some embodiments, the filament plastically deforms in responseto at least one second force applied to the filament from translating the substrate along the at least one axis.

[0042] In some embodiments, the apparatus further includes a controller and at least one motor to move the substrate along the at least one axis. In some embodiments, the controller controls the at least one motor to translate the substrate along the at least one axis to maintain the filament at the certain angle during printing of a corresponding segment of the workpiece. In some embodiments, the controller controls the at least one motor to translate the substrate along the at least one axis to apply at least one second force onto the filament, the at least one second force configured to break the filament from the printed workpiece.

[0043] In some embodiments, the filament feeder is rotatable about an axis to vary a density of the workpiece, wherein the controller controls the rotation of the filament feeder about the axis.

[0044] Figure 1 is a flowchart illustrating an example method 100 of 3D printing lattices using glass or other materials, such as aluminum or other metals.

[0045] As shown in Figure 1, an example method 100 may include operation 102, aligning a filament feeder and laser at a global origin and preheating a filament. The example method may further include, at operation 104 intersecting a substrate with the feed filament at a first location. The example method may further include, at operation 106, moving the substrate while feeding the filament. The laser can, in some embodiments, be turned off when moving the substrate. The laser can, in other embodiments, be turned off while the substrate moves relative to the filament feeder. After creating a bond with the substrate, the substrate is moved relative to the filament feeder and / or laser at the feeder angle Of to form a respective strut member or strut. The strut member, or strut, is an elongated segment extending between two joints. The example method may further include, at operation 108, turning the laser back on to heat and breaking the end of the filament feed to define a first strut. The length of the struts can, in some embodiments, be less than the final desired length of the respective strut (measured joint-to-joint). The length can be less than the final desired length so that the subsequent struts can be deposited. For example, the subsequent struts can be fabricated in subsequent layers. The example method may further include, at operation 110, rotating the substrate about a common center of intended group of struts by a first angle. The group of struts can, in some embodiments, include at least two struts. The group of struts can, in some embodiments, be a tripod formed from three struts. The example method may further include, at operation 112, feeding filament to at least one additional location and repeating operations 102-108 to deposit at least one additional strut.

[0046] Figure 2 is a flowchart illustrating an example method 200 of 3D printing lattices using glass or other materials. The other materials can be ceramics such as Alumina, or certain metals based on the thermal conductivity of the metals. The example method may further include, at operation 202, feeding filament to a second location and depositing a second strut by repeating operations 102-110. The example method may further include, at operation 204, rotating the substrate about the common center of struts by a second angle and feeding filament to third location and depositing a third strut by repeating operations 102- 110. The first strut, second strut, and the third strut may be respective struts defining a group of struts. The example method may further include, at operation 206, creating and centering a top joint of the group of struts. The workpiece can, in some embodiments, include at least two struts. The workpiece can, in other embodiments, include at least three struts. The top joint can, in some embodiments, create a tripod from three struts. The workpiece can, in other embodiments, include three or more struts. The example method may further include, at operation 208, repeating operations 102-110 to create at least one subsequent group of struts. That is, the at least one subsequent group of struts is printed based on repeating the operations for depositing the previous group of struts. The subsequent group of struts can be a subsequent tripod. Operation 208 may further include repeating operations 102-112 of Figure 1 and operations 202-206 of Figure 2 to create a subsequent pod. The example method may further include, at operation 210, fusing the pod to subsequent pods at one or more joints. Each pod may, in some embodiments, be tripods.

[0047] Figure 3 is a flowchart illustrating an example method 300 of 3D printing lattices using glass or other materials. The example method may further include, at operation 302, repeating operation 208 to create a first layer of lattice of a plurality of groups of struts, the plurality of groups of struts defining a first layer. The group of struts may be tripods. The example method may further include, at operation 304, creating at least one second layer of lattice on top of the first layer. The example method may further include, at operation 306, repeating operation 302 to create subsequent layers. Further detail on operations 102-306 are provided in Figures 5-13, and described in detail, below.

[0048] Figure 4 is a front perspective illustrating an example system 400 of a 3D print assembly. System 400 may be configured to implement the techniques described herein, although other systems are possible. System 400 can be utilized to perform method 100 of Figure 1, method 200 of Figure 2, and method 300 of Figure 3, although other methods may be possible.

[0049] System 400 can be configured to 3D print workpieces such as, for example, workpiece 402 using additive manufacturing techniques applied to filaments. The filaments may be made of silica glass or can have silica glass fibers, although other materials may also be possible. System 400 may include a filament feeder 404, a light emitting device 406, a sensor 408, and a substrate 410. The filament feeder 404 can feed a filament 412 at a specified rate, which can be to apply a force onto the workpiece when the filament 412 has been sufficiently heated using the device 406 to fuse the glass to itself or to another member. The device 406 can be an emitter that emits a light radiation beam having a certain wavelength onto a workpiece area. The sensor 408 can be positioned to capture an image of the light radiation beam such as, for example, when it intersects with the filament 412 during preheating and / or when the filament 412 is being deposited onto the substrate 410.

[0050] The filament feeder 404 can feed the filament 412 at a same rate as the system 400 is adapted to move the substrate along the multiple axes. The filament feeder 404 can also, in some embodiments, be adapted to feed the filament 412 at a controlled angle. The angle that the filament 412 is fed by the filament feeder 404 can, in some embodiments, be computer controlled to allow for more precise control of the deposition process. The angle that the filament 412 is fed relative the substrate 410 can, in some embodiments, be rotated about an axis, and the feed angle can be changed to allow the density of the lattice to be varied. In some embodiments, the workpiece 402 can be printed into a primitive rhombohedral lattice onto the substrate 410. Additionally, the workpiece 402 can be rotated to place each member at the same angle to the surface normal, but the density of the nodes can be adjusted by translating them in the direction of the gradient of a density function, and the workpiece 402 is then printed according to the defined minimum and maximum angles and minimum and maximum strut length constraints of the corresponding deposition process.

[0051] The filament 412 can be a continuous member such as, for example, from a spool of the filament 412 that can be fed out at a rate and direction suitable to minimize lateral forces on the weld before the filament 412 is intentionally broken. According to some embodiments, the filament 412 can be a non-metallic filament that plastically deforms in response to forces exerted onto the non-metallic filament once heated to a desired temperature. The filament 412 is handled cold. The forces that can be applied onto the workpiece can include a first force applied through the filament 412. The filament 412 can, in some embodiments, be a silica glass filament. For example, the filament 412 can be SMF-28 optical fiber feedstock. The filament 412 can, in some embodiments, include silica fibers. The filament 412 can, in some embodiments, be a borosilicate filament. The filament 412can, in some examples, be heated to a temperature of about 810 °C by the laser 406, which is the softening point of borosilicate glass.

[0052] The filament 412 can have a certain thickness. The filament 412 can, in some embodiments, have a thickness of 2 mm, although thicknesses greater than or less than 2 mm may be possible.

[0053] The filament 412 can be used to print a finished workpiece that is a free-standing silica (SiC>2) lattice structure having a lower density, a higher tensile strength, and a lower coefficient of thermal expansion compared to workpieces made of metallic filaments. The finished workpiece can be a plurality of free-standing members, each free-standing member being fused to at least one other free-standing member at a respective joint using the techniques described herein.

[0054] It should be appreciated that the system 400 is not intended to be limited to printing using filament 412 and can be adapted to print workpieces using different types of filaments, which can include different types of silica glass filaments and / or different types of metallic filaments, ceramic filaments, thermoplastic filaments, among other filaments. The filament 412 can, in some embodiments, be an alumina filament. When the filament is made of alumina, the welds at the joints of the workpiece 402 can be small enough that thermal expansion does not damage the lattice structure. The filament 412 can, in other embodiments, be a ceramic filament. The filament 412 can, in yet other embodiments, be a metal filament. The metal filament can be a structurally amorphous metal or high entropy alloy. When using the metal filament, the process parameters of system 400 can be selected to minimize the amount of material that crystallizes from the deposition process. System 400 can be adapted to use ceramic filament because ceramic can go to higher temperatures without the undesirable side effects to create light weight high temperature structures for applications such as, for example, the nuclear industry or aerospace industries, although other applications may be possible. For example, the lattice structures can also be used for heat exchanges.

[0055] Additionally, with metal structures made from metallic filaments, the toughness of the resulting finished workpieces can be much higher than compared to glass and ceramic workpieces, which opens up many potential applications. In both cases, it should be appreciated that the characteristics of the different types of filaments may differ (melting with a sharp change in viscosity). However, it should be appreciated that the techniques described in this application, including the constant angle that the filament is fed relative to the substrate surface to print and minimal force during extrusion except for along the feed axis,are similarly controlled when printing 3D workpieces using the other types of filaments and is not limited to solely being applied to silica glass filaments.

[0056] The light emitting device 406 can, in some embodiments, be a CO2 Light Amplification by Stimulated Emission or Radiation (Laser) device configured to emit a focused light beam having a certain wavelength to cause excitation of the phonon nodes of the filament 412 and heat the filament 412. The focused light beam can, in some examples, have a wavelength of 10.6 pm, although other wavelengths may be possible. The device 406 can be other types of lasers, which can be dependent on the filament 412 type. The device 406 is not intended to be limited to lasers and can include other types of heating devices including welding devices, although other devices may be possible. The welding devices can include, for example, Metal Inert Gas (MIG) welders, Gas Metal Arc Welding (GM AW) welders, Tungsten Inert Gas (TIG) welders, plasma arc welders, electron beam, among other types of devices which can heat the filament to a desired temperature for deposition onto the substrate 410 and to fuse members together to build the finished workpieces.

[0057] Sensor 408 can be a camera used to monitor the light beam’s interaction with the filament 412 during the printing process. Sensor 408 can be a camera that is capable of monitoring a certain wavelength or a certain wavelength range suitable to monitor the heating of the filament 412 by the device 406. The sensor 408 can be a spectrometer that can monitor a scene including the filament 412 as it intersects with the device 406 and is used to print the workpiece on the substrate 410. The sensor 408 can, in some embodiments, be an infrared (IR) camera, although other sensors may be possible. System 400 can, in some embodiments, include at least one sensor 408. The system 400 can, in some embodiments, include camera 408a and camera 408b. Camera 408a is an infrared camera to monitor the light beam’s intersection with the filament 412. Camera 408b is a camera to monitor the scene of the deposition of the filament 412 onto the surface of the substrate 410 and / or onto a lower layer of the workpiece 402.

[0058] Substrate 410 can be part of an assembly 414 that precisely controls the movement of substrate 410 along multiple axes by a controller or by a computing device. The substrate 410 can, in some embodiments, be precisely controlled to move along at least one axis to translate the workpiece 402 into desired positions and to cause the workpiece 402 to move along a feed angle relative to the filament feeder 404 and / or the device 406 to limit a side or angular force that is applied to the molten filament 412 during deposition. The assembly can, in some embodiments, be controlled to move the substrate 410 along the XYZ coordinate system of the substrate 410.

[0059] The assembly 414 can, in some embodiments, be controlled to precisely move the substrate 410 along five axes according to the XYZ coordinate system of the substrate 410. The movement of the substrate 410 can also be based on the global coordinate system. The assembly 414 can further include one or more components to precisely control the positioning and movement of the substrate 410 with sub-micrometer or nanometer accuracy. The one or more components of assembly 414 can include, for example and without limitation, motors, bearings, actuators, etc. The motors can be, for example, brushless linear motors, stepper motors, or ball screw motors, although other motors may be possible. The bearings can be, for example, mechanical bearings or air bearings, although other bearings may be possible. The assembly for moving the substrate 410 can, in some examples, be a moving gantry to move the substrate 410 along the multiple axes.

[0060] In some examples, system 400 can include a robot 416 including a robotic arm that can have the filament feeder 404 attached to a distal end thereof. The robotic arm can be controlled by a controller or computing system to precisely position the filament feeder 404 relative to the surface of the substrate 410. The robotic arm can also control precise movement of the filament feeder 404 relative to the substrate 410 during the deposition of the filament 412 to apply force onto the workpiece 402. That is, the force applied by the filament 412 can be from the feeding of the filament 412, the movement of the filament feeder 404 by the robotic arm, or both. The robotic arm can, in some embodiments, include one or more motors designed to enable one or more segments of the robotic arm to articulate, thereby causing multi-axis movement of the filament feeder 404 relative to the substrate 410 and / or the device 406 during the deposition process.

[0061] It should be appreciated that even though angular forces relative to the feed angle during the deposition of the filament 412 when printing the workpiece may be undesirable, the system 400 may be capable of selectively heating the filament 412 to form bends in the segment(s) that are being fed from the filament feeder 404. The geometry of the bent segment from the filament 412 during the deposition process can be a function of the temperature and pressure applied to the filament 412 at the bend location.

[0062] System 400 can, in some embodiments, be adapted to overcome challenges associated with asymmetric heating of the filament 412 by the device 406. Similar to bending of the filament 412, the joint geometry is a function of the temperature and pressure at the joint location. Asymmetric heating of the filament 412 can lead to sagging of the strut segments due to gravity. To overcome these challenges, the system 400 can include at least one mirror (not shown), which can be adapted to heat the filament 412 from a side where theemitted light beam contacts the side surface of the filament 412 to the opposite side to prevent asymmetric heating and sagging resulting from therefrom. System 400 can, in some embodiments, further include at least one mirror arranged to direct the emitted light radiation beam from the device 406 towards the intersection and onto one or more sides of the filament 412 to coaxially heat the absorbing filament 412 to the desired temperature and for more uniform thermal distribution through the filament 412 to avoid potential sagging. The at least one mirror can, in some embodiments, include a first mirror. The first mirror can be an off-axis parabolic (OAP) mirror to direct the light beam to the intersection to coaxially heat the filament 412. The at least one mirror can, in some embodiments, further include a second mirror. The second mirror can be a cold mirror to reflect some wavelengths of light while allowing infrared radiation to pass through. The second mirror can, in some embodiments, split the emitted light beam into a first beam and a second beam, which can be directed to the intersection with the filament 412 by the first mirror.

[0063] System 400 may be utilized to print lightweight lattice structures from glass silica filaments with high accuracy, the structures having high stiffness and low thermal expansion from the materials used to form the structures. Glass silica filaments may be used instead of certain metallic filaments due to silica glass filament having higher stiffness to density ratio, lower coefficient of thermal expansion, and greater maximum service temperature. Glass silica filaments can also have greater tensile strength than metallic structures. For example, the glass silica filament can have these improved properties relative to titanium structures. In some non-limiting examples, the system 400 may be used to print structural elements in orbiting craft located in space, or some other vacuum environment, for precise relative positioning of critical space craft elements such as, for example, large antenna arrays. The environment that the workpiece is being utilized can, in some embodiments, have less than 1 G of gravity. It is attractive to use filaments that provide structures with these properties because the loading in orbit is much less than during launch. These applications of system 400 are not intended to be limiting and there may be other applications for this printing method using system 400 including, for example, fully dense lenses, functional fiber optics, capillary tubes, and freestanding spirals, although other shapes and sizes of a variety of different objects may be possible, and which are not intended to be limited to applications in space and / or in-orbit.

[0064] Workpiece 402 can have various different shapes, sizes, and / or dimensions.Workpiece 402 can, in some embodiments, be a final workpiece. Workpiece 402 can, in other embodiments, be one of a plurality of workpieces built at a respective stage and that can bejoined (e.g., fused) together to construct the final workpiece. Each workpiece can be, for example, 6” x 6” x 6”, although other dimensions may be possible. The workpiece 402 can, in some embodiments, have much larger dimensions than the previous example. The workpiece 402 can, in some embodiments, be part of a final workpiece that is several meters long or even longer. For example, the final workpiece can be 10 m long. It should be appreciated that the shape, size, and dimensions of the workpieces that can be built using the systems and methods described herein are exemplary and not intended to be limiting and can include smaller dimensions or greater dimensions than described herein.

[0065] Figure 5 illustrates a front perspective view of the example operation 102 for 3D printing lattices. In the operational step, as shown in Figure 5, the filament feeder 502 and the laser 504 are aligned so that they intersect at global origin 506. Both are in the same plane (depicted as global XZ) with the feeder 502 and laser 504 oriented at 0f, and 0i respectively. In the figure, the workpiece coordinate system (XYZ) is initially aligned to the global coordinate system. The workpiece coordinate system can, in some embodiments, be initially aligned relative to the global origin of the global coordinate system for printing a workpiece. At the start of the process, the filament 508 is fed to the point that the laser 504 heats its end. The laser 504 preheats the filament 508 end for duration n with power Pi, raising its temperature and removing unevenness from the tip of the filament 508. The point where the laser 504 heats the filament 508 is above the surface of the substrate 510, such that the filament 508 does not contact the surface of the substrate 510. The laser 504 can heat the filament 508 tip more rapidly by not being in contact with the substrate 510 so that heat is not lost to the substrate 510.

[0066] Figure 6 illustrates a front perspective view of an example operation 104 for 3D printing lattices. In another operational step, as shown in Figure 6, at the conclusion of the preheat step, the substrate 510 is brought up by V2 to intersect with the filament 508. The laser 504 heats both the substrate 510 and filament 508 for duration 12 at power P2 to the point that a strong fusion bond is formed between the glass being deposited onto the substrate 510. Pressure is maintained by the substrate 510 motion or by feeding the filament 508 at a low rate once the filament 508 and substrate 510 are in contact.

[0067] Figure 7 illustrates a front perspective view of an example operation 106 for 3D printing lattices. In the operational step, as shown in Figure 7, after creating a strong fusion bond with the substrate 510 from applying force fs, the substrate 510 is moved relative to the feeder 502 and / or laser 504 at the feeder angle, 0f. The filament 508 can be fed at a same rateas the rate of movement V3 of the substrate 510. Because there is minimal loading on the filament 508 and the laser 504 is turned off, this process of the deposition of the filament 508 to form the segment can be for duration 13. The filament 508 can, for example, be fed at a very fast rate of 100 mm / s to form the strut segment (joint-to-joint), although other rates may be possible including faster rates or slow rates than 100 mm / s based on a plurality of factors associated with the laser, filament, desired temperature, ambient temperature, viscosity, among other factors.

[0068] Figures 8A-B illustrate a front perspective view of an example operation 108 for 3D printing lattices. In the operational step, as shown in Figure 8A, when the filament 508 has reached the desired length, the laser 504 is turned back on for duration 4 at power P4 to locally heat the end of the filament 508. The substrate 510 is moved by V4 and filament 508 is moved by f4 in opposite directions (still along the feed direction) from each other to place a tensile load on the glass strut 512 (depicted as necking in the figure). It should be appreciated that strain rate and temperature of the glass strut 512 are important factors taken into consideration to generate a break in the glass at the desired location (at necking).

[0069] As shown in Figure 8B, after the filament 508 has been cut from the strut 512, the strut 512 will have a length, L. This length needs to be as consistent as possible and is slightly less than the final length of the strut (measured joint-to-joint). This reduced length is necessary so that the subsequent struts can be deposited. The subsequent struts may be in the same pod as strut 512. The subsequent struts may also be in adjacent pods and / or part of an adjacent layer. The length of the strut 512 can be measured in-situ using a camera such as camera REF of Figure 4.

[0070] Figure 9 illustrates a front perspective view of an example operation 112 for 3D printing lattices. The operational step depicted in Figure 9 can also be of an example operation 202 and 204, according to some embodiments. In the operational step, as shown in Figure 9, following the completion of the first strut 512, the substrate 510 is rotated by a certain angle about what will be the common center of the pod of struts. For example, the substrate 510 is rotated by 120 degrees about the common center of the first three struts of the first pod, the first three struts including strut 512. Figure 9 shows the geometry and arrangement of the components after this rotation with the initial strut 512 and the laser 504 preheating the filament 508 for duration n at power Pi for deposition of the next strut. The process in operations 102-108 repeats itself for each strut in the tripod. The process in operations 102-108 can, in some embodiments, repeat itself for at least one additional strut in the pod.

[0071] Figure 10 illustrates a front perspective view of an example operation 112 for 3D printing lattices. Figure 10 can depict an operational step 202, according to some embodiments. In the operational step, as shown in Figure 10, as with the first strut 512, the second strut 514 can be fed out from filament 508 for duration 13 at a same rate as the rate of movement V3 of substrate 510. The filament 508 can be fed out at a rate from force f3 that is as fast as possible (and that matches the rate of movement of the substrate 510) once a good fusion bond is made with the substrate 510. This limited deflection provided by the techniques described herein facilitates the fast rate of deposition of filament 508 in forming the workpiece segments, which is a key advantage over conventional approaches. The figure also shows that it is critical that the length of the struts be short enough that they do not interfere with the deposition of subsequent struts.

[0072] Figure 11 illustrates a front perspective view of an example operation 204 for 3D printing lattices. In another operational step, as shown in Figure 11, after rotating the substrate 510 another the certain angle about the common center of the struts in the pod, operations 102-110 are repeated with the third strut. The substrate 510 can, in some embodiments, be rotated by 120 degrees about the common center of the struts to from a third strut of a tripod, although other angles may be possible depending on the number of struts in the pod. Although not shown in Figure 11, the laser 504 passes between the first two struts 512, 514 to heat the filament to make the fusion bond with the substrate 510 such as described in regard to Figure 6. The figure shows the rapid feed step for the third strut 516 and movement of the substrate 510 by V7 in a similar manner as for strut 512 and strut 514.

[0073] Figure 12 illustrates a front perspective view of an example operation 206 for 3D printing lattices. In another operational step, as shown in Figure 12, the completion of the third strut 516 involves stopping the stage while feeding the filament 508 and then a translation of the substrate 510 towards the first two struts 512, 514 in order to center the feeder 502 and the laser 504 relative to a top joint 518. The filament 508 can then be withdrawn under laser 504 heating to break off the strut 516. The substrate 510 can, in some embodiments, be moved by rate Vs in a certain direction to break off the filament 508 from the strut 516 and / or the top joint 518. The joint 518 can also be heated subsequently by the laser 504 for duration rs at power Ps to make the joint 518 more spherical in shape.

[0074] Figure 13 illustrates a front perspective view of an example operation 208 for 3D printing lattices. Figure 13 can, in some embodiments, also illustrate an example operation 210 for fusing a pod to a subsequent pod at one or more joints. In another operational step, as shown in Figure 13, after the first pod 520a is created, subsequent pods 520n can bedeposited by translating the local coordinate system relative to the global coordinate system, and depositing the filament 508 to form the subsequent pods 520n in a similar manner as the first pod 520a. The first pod 520a can be fused to one or more subsequent pods 520n.

[0075] Figure 14 illustrates a front perspective view of an example operation 302 for 3D printing lattices. In another operational step, as shown in Figure 14, this procedure continues for each pod 520a-n in the first layer 522. There may be an exception in that some of the pods located at a side of the first layer 522 may have a different configuration than pod 520a, for example, in some embodiments, some of the units of pods on the side of the lattice at a given layer may have a fewer number of struts. For example, some of the pods may have two struts instead of three struts. The pods 520 in a layer can have a staggered arrangement, which allows the laser 504 to have access to the top and bottom joints of each pod 520 when the pods 520 and their corresponding struts are printed sequentially. The figure shows a 5x4 lattice.

[0076] Figure 15 illustrates a front perspective view of an example operation 304 for 3D printing lattices. In another operational step, as shown in Figure 15, after the completion of the first layer 522, the printing of the second layer 524 proceeds using the same pattern as the first layer 522. The lattice is shifted so that each new pod 520 (e.g., "tripod") is supported by the apex of the three joints from the previous layer such as, for example, top joint 518 of the first pod 520a. The figure shows the unheated extrusion step of the first strut 512b on the second layer 524, which can be followed by the second strut 514b, the third strut 516b, and so forth to print the pods 520 of the second layer 524 and so forth.

[0077] Figure 16 illustrates a front perspective view of an example operation 306 for 3D printing lattices. In another operational step, as shown in Figure 16, each subsequent layer proceeds on top of earlier layers such as, for example, layers 1-4 as shown in Figure 16. In some examples, the workpiece is designed to have a 20-lattice geometry which repeats itself after 3 layers, and layer 4 has the same layout as layer 1 but shifted up by 3-L-cos(0). This pattern can be repeated for as many layers as are desired (or based on the maximum travel of the stages).

[0078] Throughout the specification and claims, the following terms take the meanings explicitly associated herein, unless the context clearly dictates otherwise. The phrases "in one embodiment," “in an embodiment,” and "in some embodiments" as used herein do not necessarily refer to the same embodiment(s), though it may. Furthermore, the phrases "in another embodiment" and "in some other embodiments" as used herein do not necessarilyrefer to a different embodiment, although it may. All embodiments of the disclosure are intended to be combinable without departing from the scope or spirit of the disclosure.

[0079] As used herein, the term "based on" is not exclusive and allows for being based on additional factors not described, unless the context clearly dictates otherwise. In addition, throughout the specification, the meaning of "a," "an," and "the" include plural references. The meaning of "in" includes "in" and "on."

[0080] As used herein, the term “between” does not necessarily require being disposed directly next to other elements. Generally, this term means a configuration where something is sandwiched by two or more other things. At the same time, the term “between” can describe something that is directly next to two opposing things. Accordingly, in any one or more of the embodiments disclosed herein, a particular structural component being disposed between two other structural elements can be: disposed directly between both of the two other structural elements such that the particular structural component is in direct contact with both of the two other structural elements; disposed directly next to only one of the two other structural elements such that the particular structural component is in direct contact with only one of the two other structural elements; disposed indirectly next to only one of the two other structural elements such that the particular structural component is not in direct contact with only one of the two other structural elements, and there is another element which juxtaposes the particular structural component and the one of the two other structural elements; disposed indirectly between both of the two other structural elements such that the particular structural component is not in direct contact with both of the two other structural elements, and other features can be disposed therebetween; or any combination(s) thereof.

[0081] The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

CLAIMSWhat is Claimed Is:

1. A method of forming 3-dimensional (3D) workpieces using depositional printing, the method comprising:aligning a filament feeder and laser at a global origin and preheating a filament; intersecting a substrate with a filament at a first location;moving the substrate while feeding the filament with the laser turned off; turning the laser back on to heat and breaking an end of the filament to define a first strut;rotating the substrate about a common center of intended group of struts by a first angle; andfeeding filament to at least one additional location and depositing at least one additional strut to print the group of struts.

2. The method according to claim 1, wherein feeding filament to the at least one additional location and depositing the at least one additional strut to print the group of struts comprises:feeding the filament to a second location and depositing a second strut;rotating the substrate about the common center of struts by a second angle and feeding the filament to a third location and depositing a third strut;creating and centering a top joint of the group of struts; andcreating at least one subsequent group of struts,wherein the second strut and the third strut are printed based on repeating the aligning, intersecting, moving, and breaking operations for depositing the first strut, and wherein the at least one subsequent group of struts is printed based on repeating the operations for depositing the group of struts.

3. The method according to claim 2, wherein creating the at least one subsequent group of struts comprises:creating a first layer of lattice from a plurality of group of struts; andcreating at least one second layer of lattice on top of the first layer.

4. A system comprising:a device configured to emit a light radiation beam having a certain wavelength; a feeder positioned relative to the device, the feeder configured to feed a non-metallic filament at a feed rate;a substrate having a surface for deposition of the non-metallic filament during a deposition process; andat least one sensor positioned to capture an image of an intersection of the filament and the light radiation beam;wherein the light radiation beam heats the non-metallic filament to a temperature to enable deposition of the non-metallic filament onto the substrate surface at a first angle to print a workpiece, and wherein the substrate is translatable along at least one axis at a second rate to minimize forces on the non-metallic filament and to maintain the non-metallic filament at the first angle, the second rate being based on the feed rate.

5. The system according to claim 4, wherein the device is a CO2 laser device configured to emit a focused light beam having a wavelength of 10.6 pm.

6. The system according to claim 5, further comprising:at least one mirror to coaxially heat the non-metallic filament with the light radiation beam during the deposition process.

7. The system according to claim 4, wherein the non-metallic filament plastically deforms in response to one or more forces exerted onto the non-metallic filament when heated to the temperature.

8. The system according to claim 7, wherein the non-metallic filament is handled cold, andwherein the forces comprise a first force applied from feeding the non-metallic filament.

9. The system according to claim 8, further comprising:a controller; andan assembly comprising:the substrate, andat least one motor to cause the substrate to move along the at least one axis, wherein the controller controls the at least one motor to translate the substrate along the at least one axis to maintain the non-metallic filament at the first angle during printing of the workpiece, and wherein the controller controls the at least one motor to translate the substrate along the at least one axis to apply at least one second force onto the non-metallic filament, the at least one second force configured to break the non-metallic filament from the printed workpiece.

10. The system according to claim 9, wherein the feeder is rotatable about an axis to vary a density of the workpiece, wherein the controller controls the rotation of the feeder about the axis.

11. The system according to claim 4, wherein the non-metallic filament comprises silica fibers.

12. The system according to claim 11, wherein the non-metallic filament is a borosilicate filament.

13. The system according to claim 11, wherein a finished workpiece is a free-standing silica (SiCh) lattice structure having a lower density, a higher tensile strength, and a lower coefficient of thermal expansion compared to workpieces made of metallic filaments.

14. The system according to claim 13, wherein the finished workpiece comprises a plurality of free-standing members, each free-standing member being fused to at least one other free-standing member at a respective joint.

15. An apparatus for printing 3D workpieces, comprising:a device configured to heat a filament to a temperature;a filament feeder positioned relative to the device and configured to feed the filament at a first rate;a substrate having a surface for deposition of the filament during a deposition process, the substrate being translatable along at least one axis to maintain the filament at a certain angle during the deposition of the filament; andat least one sensor positioned to capture an image of the heating of the filament to the temperature and the deposition of the filament onto the surface during the deposition process,wherein the device heats the filament to a temperature to enable deposition of the filament onto the surface at the certain angle, and wherein the substrate is translatable along the at least one axis at a second rate to minimize forces on the filament, the second rate being based on the first rate.

16. The apparatus according to claim 15, wherein the device is a CO2 laser device configured to emit light radiation beam having a wavelength of 10.6 pm.

17. The apparatus according to claim 15, wherein the filament is a silica glass filament, and wherein a finished workpiece printed from the silica glass filament comprises a 3D lattice structure having a lower density, a higher tensile strength, and a lower coefficient of thermal expansion compared to workpieces printed from metallic filaments.

18. The apparatus according to claim 15, wherein the filament is handled cold, and wherein, when heated to the temperature, the filament plastically deforms in response to a first force applied from feeding the filament, andwherein the filament plastically deforms in response to at least one second force applied to the filament from translating the substrate along the at least one axis.

19. The apparatus according to claim 17, further comprising:a controller;at least one motor to move the substrate along the at least one axis,wherein the controller controls the at least one motor to translate the substrate along the at least one axis to maintain the filament at the certain angle during printing of a corresponding segment of the workpiece, and wherein the controller controls the at least one motor to translate the substrate along the at least one axis to apply atleast one second force onto the filament, the at least one second force configured to break the filament from the printed workpiece.

20. The apparatus according to claim 19, wherein the filament feeder is rotatable about an axis to vary a density of the workpiece, wherein the controller controls the rotation of the filament feeder about the axis.

Images