WO2025090960A1

WO2025090960A1 - High-temperature low-friction extrusion system for metal additive manufacturing

Info

Publication number: WO2025090960A1
Application number: PCT/US2024/053108
Authority: WO
Inventors: Austin RAY; Michael Knotts; Travis Thompson
Original assignee: Generational Systems LLC
Current assignee: Generational Systems LLC
Priority date: 2023-10-27
Filing date: 2024-10-25
Publication date: 2025-05-01
Anticipated expiration: 2026-04-27

Abstract

An extrusion system (10) for providing a wire feedstock (12) to a print head (18) of a 3D printer (14) is disclosed. The extrusion system (10) may include an extruder assembly (22) and a feed line (38) defined by at least one extrusion tube (40) is disclosed. The extruder assembly (22) may be configured to drive the wire feedstock (12) into the print head (18). The feed line (38) may include an extruder end (42) configured to receive the wire feedstock (12) from the extruder assembly (22) and a print head end (44) configured to provide the wire feedstock (12) to the print head (18). The extruder assembly (22) may include a base (24), a drive roller (26) rotatably attached to the base (24), a motor (23) connected to and configured to rotate the drive roller (26), and an idler block (30) pivotally connected to the base (24).

Description

HIGH-TEMPERATURE LOW-FRICTION EXTRUSION SYSTEM FOR METAL

ADDITIVE MANUFACTURING CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This is an international application claiming priority to U.S. Provisional Patent Application Serial No. 63/546,134 filed October 27, 2023, and entitled “High-Temperature Low-Friction Extrusion System For Metal Additive Manufacturing.” TECHNICAL FIELD

[0002] The present disclosure relates generally to the field of additive manufacturing, also known as 3D printing. More particularly, the present disclosure pertains to high-temperature low- friction extrusion systems for metal 3D printers for used to additively manufacture metallic articles.

BACKGROUND ART

[0003] Metal additive manufacturing, commonly known as metal 3D printing, utilizes various methods to create solid metal objects. Many methods of metal additive manufacturing, such as powder bed fusion, direct energy deposition, binder jetting, and bound powder extrusion use, involve depositing metal powder feedstock onto a printing area and applying heat to bind the powder into a solid object. Recent improvements in metal additive manufacturing allow for the use of metal wire or metal rod feedstock which are melted and formed into a solid object. Metal wire or rod feedstocks are less expensive and safer to handle than metal powder feedstock. [0004] Some 3D printers that utilize metal wire or rod feedstocks use extrusion systems to drive the metal feedstock to the location where it is to be deposited, at which point focused thermal energy, such as lasers, electron means, or plasma arcs, is used to melt the incoming metal feedstock as it is deposited. Such 3D printers have low print resolutions and are only feasible for use in large-scale printing. Such 3D printers are often large and expensive.

[0005] Alternative methods of melting metal wire or rod feedstocks, such as induction heating, melt the feedstock prior to deposition. An extrusion system may drive the metal feedstock into a print head where melting occurs. The print head then deposits the molten metal from a nozzle to form a solid object. 3D printers utilizing such methods are capable of creating smaller, higher resolution builds at a lower cost. However, pre-melting the metal feedstock may be energy intensive due to the high temperatures required to melt metal commonly used in 3D printing and maintain them in a molten state until deposition. Pre-melting the metal feedstock can also be energy inefficient as significant amounts of heat are lost to the ambient environment.

[0006] Moreover, the heated or molten metal may be sensitive to changes in ambient conditions, such as temperature or the composition of the ambient air. Some metal 3D printing techniques require shielding gas to prevent unintentional oxidation of the metal in the printed object. One option for increasing the energy efficiency of 3D printing and maintaining the ambient conditions during 3D printing is to use a 3D printer having an enclosed build chamber within which 3D printing occurs. Such build chambers can insulate the 3D printing process from changes in ambient conditions and increase the energy efficiency of 3D printing but may cause issues with feeding the raw feedstock to the 3D printer due to the high temperatures within the build chamber. Particularly, the high temperatures within the build chamber may (1) weaken or prematurely melt the incoming feedstock, causing binding within the extrusion system, or (2) result in the oxidation of the incoming feedstock, which may compromise the properties of the resulting 3D-printed object.

SUMMARY OF INVENTION [0007] To overcome at least some of the above-referenced problems in metal additive manufacturing, an exemplary object of the present disclosure is to provide a high-temperature, low-friction extrusion system for consistently driving feedstock into a 3D printer while preventing binding or oxidation of the feedstock. In some embodiments, the present disclosure provides an extrusion system for providing a wire feedstock to a print head of a 3D printer. The extrusion system may include an extruder assembly configured to drive the wire feed stock into the print head and a feed line defined by at least one extrusion tube. The feed line may include an extruder end secured to and configured to receive the wire feedstock from the extruder assembly, a print head end opposite the extruder end and configured to secure to and provide the wire feedstock to the print head, and an insulative sleeve disposed around the feed line. [0008] In a particular embodiment, an exemplary extrusion system for providing a wire feedstock to a print head of a 3D printer as disclosed herein may include an extruder assembly and a feed line. The extruder assembly may be configured to drive the wire feedstock into the print head. The feed line may be defined by at least one extrusion tube. The feed line may include an extruder end, a print head end, and an insulative sleeve disposed around the feed line. The extruder end may be secured to and configured to receive the wire feedstock from the extruder assembly. The print head end may be opposite the extruder end and configured to secure to and provide the wire feedstock to the print head.

[0009] In an exemplary aspect according to the above-referenced embodiment, the insulative sleeve may be heat resistant up to a temperature of 700 °F. [0010] In another exemplary aspect according to the above-referenced embodiment, the insulative sleeve may limit a flow rate of heat into the feed line through the insulative sleeve to less than 1 BTU/hr at 800 °F.

[0011] In another exemplary aspect according to the above-referenced embodiment, the insulative sleeve may comprise at least two insulation layers formed from at least two different materials.

[0012] In another exemplary aspect according to the above-referenced embodiment, the insulative sleeve may comprise alumina oxide ceramic fiber.

[0013] In another exemplary aspect according to the above-referenced embodiment, the insulative sleeve may comprise a flexible insulation layer that is helically wrapped around the feed line and one or more metallic wires that are helically wrapped around the insulation layer. [0014] In another exemplary aspect according to the above-referenced embodiment, the insulative sleeve may comprise a flexible, expandable outer layer configured to slide over the insulation layer and one or more wires when the outer layer is compressed and to tighten to secure the insulation layer and one or more wires.

[0015] In another exemplary aspect according to the above-referenced embodiment, the extrusion system may further comprise a first fastener and a second fastener. The insulative sleeve may comprise a first end and a second end opposite the first end. The first fastener may be secured around the insulative sleeve first end and the second fastener may be secured around the insulative sleeve second end.

[0016] In another exemplary aspect according to the above-referenced embodiment, the at least one extrusion tube may be a low-friction extrusion tube.

[0017] In another exemplary aspect according to the above-referenced embodiment, the at least one extrusion tube may comprise Teflon. [0018] In another exemplary aspect according to the above-referenced embodiment, the feed line may further comprise a first extrusion tube positioned adjacent the extruder end, a second extrusion tube positioned adjacent the print head end, and a three-way connector including a feedstock inlet connected to the first extrusion tube, a feedstock outlet connected to the second extrusion tube, and a shielding gas inlet configured to receive shielding gas from a shielding gas source.

[0019] In another embodiment, an exemplary table saw dust deflection system as disclosed herein may include the extruder assembly may include a base, a drive roller, a motor, and an idler block. The drive roller may be rotatably attached to the base. The motor may be connected to and configured to rotate the drive roller. The idler block may be pivotally connected to the base and comprise a clutch roller rotatably attached to the idler block. The idler block may be configured to pivot to move the clutch roller between a feed position in which the clutch roller compresses the wire feedstock against the drive roller such that rotation of the drive roller by the motor drives the wire feedstock into the feed line and an idle position in which the clutch roller and drive roller are spaced apart such that rotation of the drive roller by the motor does not drive the wire feedstock into the feed line.

[0020] In another exemplary aspect according to the above-referenced embodiment, the idler block may comprise an inlet duct for receiving the wire feedstock. The base may comprise a feed block secured to the feed line and including an outlet duct. The outlet duct may be aligned with the inlet duct and the feed line to allow the wire feedstock to pass from the inlet duct through the outlet duct into the feed line.

[0021] In a particular embodiment, an exemplary 3D printer for forming a 3D object from a wire feedstock as disclosed herein may include a frame, a print hear, and an extrusion system. The print head may be connected to the frame and configured to melt and deposit the wire feedstock to form the 3D object. The extrusion system may be configured to provide the wire feedstock to the print head. The extrusion system may include an extruder assembly and a feed line. The extruder assembly may be secured to the frame and configured to drive the wire feedstock into the print head. The feed line may be defined by at least one extrusion tube. The feed line may include an extruder end, a print head end, and an insulative sleeve disposed around the feed line. The extruder end may be secured to and configured to receive the wire feedstock from the extruder assembly. The print head end may be opposite the extruder end and configured to secure to and provide the wire feedstock to the print head.

[0022] In an exemplary aspect according to the above-referenced embodiment, the print head end may be secured to the print head by a fitting that is a high-temperature compression fitting or push-to-connect fitting.

[0023] In another exemplary aspect according to the above-referenced embodiment, the 3D printer may further comprise a support bracket secured to the feed line adjacent the fitting.

[0024] In another exemplary aspect according to the above-referenced embodiment, the 3D printer may further comprise an enclosed build chamber having an exterior wall. The extruder assembly may be disposed external to the build chamber and the print head may be disposed within the build chamber. The feed line may extend from the extruder assembly through the exterior wall to the print head.

[0025] In another exemplary aspect according to the above-referenced embodiment, the insulative sleeve may be disposed around the feed line between the exterior wall and the print head end.

[0026] In another exemplary aspect according to the above-referenced embodiment, the 3D printer may further comprise a shielding gas source for providing shielding gas to the extrusion system. The feed line may comprise a first extrusion tube adjacent the extruder end, a second extrusion tube adjacent the print head end, and a three-way connector including a feedstock inlet connected to the first extrusion tube, a feedstock outlet connected to the second extrusion tube, and a shielding gas inlet configured to receive shielding gas from the shielding gas source. [0027] In another exemplary aspect according to the above-referenced embodiment, the wire feedstock may have an outer diameter and the at least one extrusion tube may have an inner diameter. A difference in the outer diameter of the wire feedstock and the inner diameter of the tube may be between about 0.010 inches and 0.050 inches.

[0028] In another exemplary aspect according to the above-referenced embodiment, the print head may be configured to melt and deposit the wire feedstock at a deposition point. The print head may be disposed at a distance from the deposition point.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Fig. 1 shows a side elevation view of an embodiment of a feedstock spool and extruder assembly of a 3D printer in accordance with the present disclosure. [0030] Fig. 2 shows a side elevation view of a feedline of the extruder assembly of the 3D printer of Fig. 1.

[0031] Fig. 3 shows a front, side perspective view of an embodiment of a print head of the 3D printer of Fig. 1.

[0032] Fig. 4 shows a top, side perspective view of an embodiment of an extrusion system in accordance with the present disclosure.

[0033] Fig. 5A shows a rear, top perspective view of the extruder assembly of the extrusion system of Fig. 4.

[0034] Fig. 5B shows a top plan view of an embodiment of the extruder assembly of the extrusion system of Fig. 4. [0035] Fig. 6A shows a top plan view of the feed line of the extrusion system of Fig. 4.

[0036] Fig. 6B shows a cross-sectional perspective view of the feed line of the extrusion system of Fig. 4. DESCRIPTION OF EMBODIMENTS

[0037] Reference will now be made in detail to embodiments of the present disclosure, one or more drawings of which are set forth herein. Each drawing is provided by way of explanation of the present disclosure and is not a limitation. It will be apparent to those skilled in the art that various modifications and variations can be made to the teachings of the present disclosure without departing from the scope of the disclosure. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment.

[0038] Thus, it is intended that the present disclosure covers such modifications and variations as come within the scope of the appended claims and their equivalents. Other objects, features, and aspects of the present disclosure are disclosed in, or are obvious from, the following detailed description. It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only and is not intended as limiting the broader aspects of the present disclosure.

[0039] Unless specifically stated otherwise, any part of the apparatus of the present disclosure may be made of any appropriate or suitable material including, but not limited to, metal, alloy, polymer, polymer mixture, composite, or any combination thereof.

[0040] Referring to Figs. 1-6B, an extrusion system 10 for providing a feedstock 12 to a 3D printer 14 is disclosed herein. 3D printers 14 for use with the extrusion system 10 of the present disclosure may be metal 3D printers 14 that use metal wire or rods as feedstock 12, though it is understood that the extrusion system 10 of the present disclosure may be used with 3D printers 14 that use wires or rods made of plastic or other materials. Throughout the disclosure, reference may be made to a metal wire feedstock 12. However, such references are not intended to exclude the use of feedstocks 12 that are rods and/or that are made from other materials unless explicitly stated. The 3D printer 14 may include a frame 16 supporting other components of the 3D printer 14. The 3D printer 14 may also include a print head 18 connected to the frame 16 and configured to melt and deposit the metal feedstock 12 to form the 3D object. The print head 18 may deposit the molten feedstock 12 at a deposition point, and the print head 18 may be disposed at a distance from the deposition point. Additionally, the 3D printer 14 may include a build chamber 20 formed by a plurality of exterior walls disposed around the print head 18.

The build chamber 20 forms a closed environment within which the 3D printer 14 prints a 3D object.

[0041] As shown in FIGs. 5A-5B, the extrusion system 10 includes an extruder assembly 22 configured to drive the wire feedstock 12 into the print head 18. The extruder assembly 22 may be secured to the frame 16 of the 3D printer 14. The extruder assembly 22 may include a base 24, a drive roller 26 rotatably connected to the base 24, and a clutch roller 28 rotatably connected to the base 24. The drive roller 26 and clutch roller 28 may be disposed adjacent to one another such that the feedstock 12 can be fed between the drive roller 26 and clutch roller 28. The extruder assembly 22 may also include a motor 23 connected to and configured to rotate the drive roller 26. The torque output required to smoothly feed the wire feedstock 12 into the print head 18 may depend on factors such as the bend radius of the feed line 38 (discussed below), the static and kinetic coefficients of extrusion tube(s) 40 (discussed below), and the relative diameter of the wire feedstock 12 and extrusion tube(s) 40. In some embodiments, the motor 23 may have a torque greater than about 7.5 Ibf-in to consistently drive the feedstock 12 into the print head 18.

[0042] The clutch roller 28 may be configured to move between a feed position and an idle position. In the feed position, the feedstock 12 is compressed between the drive roller 26 and clutch roller 28 such that rotation of the drive roller 26 by the motor 23 drives the feedstock 12 into the print head 18. In the idle position, the drive roller 26 and clutch roller 28 are spaced such that the feedstock 12 is not compressed between the drive roller 26 and clutch roller 28, and rotation of the drive roller 26 by the motor 23 does not drive the feedstock 12 into the print head 18. A clutch motor or actuator (not shown) may move the clutch roller 28 between the feed position and the idle position.

[0043] In some embodiments, the extruder assembly 22 may include an idler block 30 pivotally connected to the base 24. When the idler block 30 is present, the clutch roller 28 may be attached to the idler block 30. The idler block 30 may pivot to move the clutch roller 28 between the feed position and the idle position. The clutch motor or actuator may pivot the idler block 30 to move the idler block 30 between the feed position and the idle position. The idler block

30 may include an inlet duct 32 for receiving and guiding the feedstock 12 between the drive roller 26 and clutch roller 28. Alternatively, the inlet duct 32 may be a separate duct or sleeve for receiving and guiding the feedstock 12 between the drive roller 26 and clutch roller 28.

[0044] The extruder assembly 22 may include a feed block 34 connected to the base 24. The feed block 34 may include an outlet duct 36 for receiving the feedstock 12 from the drive roller 26 and clutch roller 28 and guiding the feedstock 12 into the feed line 38 discussed below. The inlet duct 32 of the idler block 30 and the outlet duct 36 of the feed block 34 may be substantially aligned or colinear to allow the feedstock 12 to pass through the inlet duct 32, between the drive roller 26 and clutch roller 28, through the outlet duct 36, and into the feed line 38.

[0045] As shown in FIGs. 6A-6B, the extrusion system 10 includes a feed line 38 configured to guide the feedstock 12 from the extruder assembly 22 to the print head 18 of the 3D printer 14. The feed line 38 is defined by at least one extrusion tube 40. The extrusion tube 40 may be made from low-friction materials, such as Teflon, to allow the feedstock 12 to smoothly travel through the extrusion tube 40. The extrusion tube 40 should be able to withstand temperatures of 100 °F to 500 °F depending on the temperatures at which the 3D printer 14 will be used. For example, the extrusion tube 40 may be heat resistant up to a temperature of about 100 °F, about 200 °F, about 300 °F, about 400 °F, or about 500 °F. The size of the extrusion tube 40 may be slightly larger than the size of the feedstock 12 used to prevent the feedstock 12 from buckling when passing through the feedstock 12. For example, the inner diameter of the extrusion tube 40 may be about 0.050 inches to about 0.10 inches greater than the outer diameter of the feedstock 12. Tn other embodiments, the difference between the inner diameter of the extrusion tube 40 and the outer diameter of the feedstock 12 may be about 0.007 inches to about 0.070 inches, 0.010 inches to about 0.050 inches, 0.010 inches to about 0.030 inches, 0.020 inches to about 0.040 inches, 0.030 inches to about 0.050 inches.

[0046] The feed line 38 has an extruder end 42 and a print head end 44 opposite the extruder end 42. As shown in Figs. 1 and 4, the extruder end 42 is secured to and configured to receive the feedstock 12 from the extruder assembly 22. The extruder end 42 may be aligned with and connected to the outlet duct 36 of the feed block 34 such that the outlet duct 36 guides the feedstock 12 into the extruder end 42 of the feed line 38. The print head end 44 is configured to secure to and provide feedstock 12 to the print head 18. In some embodiments, the print head end 44 may secure to a guide tube 45 of the print head 18. The guide tube 45 may include a heat break to reduce the conduction of heat from the print head 18 into the extrusion tube(s)

40. In embodiments in which the 3D printer 14 includes a build chamber 20, the extruder assembly 22 may be disposed outside of the build chamber 20 and the print head 18 may be disposed inside of the build chamber 20. In such embodiments, the feed line 38 may extend from the extruder assembly 22 through one of the exterior walls of the build chamber 20 to the print head 18.

[0047] Fittings 46 may be used to connect the extruder end 42 of the feed line 38 to the extruder assembly 22 and the print head end 44 of the feed line 38 to the print head 18. The fittings 46 may be a compression fitting or push-to-connect fitting on the side secured to the extruder end 42 or print head end 44 of the feed line 38 and a threaded or compression-type fittings on the sides connected to the print head 18 to allow the feedstock 12 to pass from the extruder assembly 22 through the feed line 38 and into the print head 18 unobstructed. The fittings 46 may include other connection types on either side so long as the movement of the feedstock 12 from the extruder assembly 22 through the feed line 38 to the print head 18 is not obstructed or impeded.

[0048] A support bracket (not shown) may be used to provide additional rigidity at the point of connection between the print head end 44 of the feed line 38 and fitting 46. In some embodiments, the support bracket may include two 90° arms each having two halves each with a semicircle cutout. The radius of the semicircle cutout may be slightly smaller than the radius of the print head end 44 of the feed line 38. Each half may be placed around the print head end 44 of the feed line 38 such that the semicircle cutouts form a complete circle around and compress the print head end 44 of the feed line 38. The two halves of the support bracket can then be bolted together or otherwise secured to maintain the compression of and support the print head end 44 of the feed line 38. [0049] The 3D printer 14 may include a shielding gas source (not shown) for supplying shielding gas into the feed line 38 to cool and prevent oxidation of the feedstock 12. In such embodiments, the feed line 38 may include a first extrusion tube 40 A adjacent to the extruder end 42, a second extrusion tube 40B adjacent to the print head end 44, and a three-way connector 48 connecting the first and second extrusion tubes 40A, 40B. The three-way connector 48 may be a wye connector. The three-way connector 48 may include a feedstock inlet 50 connected to the first extrusion tube 40A, a feedstock outlet 52 connected to the second extrusion tube 40B, and a shielding gas inlet 54 connected to and configured to receive shielding gas from the shielding gas source. For example, a shielding gas tube 49 may connect the shielding gas source to the shielding gas inlet 54 of the three-way connector 48. The feedstock inlet 50 and feedstock outlet 52 of the three-way connector 48 may be aligned to allow the feedstock 12 to pass smoothly through the three-way connector 48. The shielding gas inlet 54 may be biased toward (i.e., form an angle of less than 90° with) the feedstock inlet 50 to direct the shielding gas toward the feedstock outlet 52 as the shielding gas flows through the three-way connector 48. When the extrusion system 10 is used with a 3D printer 14 having an enclosed build chamber 20, the three-way connector 48 may be disposed external to the build chamber 20 to reduce the number of tubes passing through the exterior walls of the build chamber 20.

[0050] The feed line 38 also includes an insulative sleeve 56 disposed around the feed line 38. The insulative sleeve 56 prevents the transfer of heat to the feedstock 12 through the feed line 38, which can oxidize the feedstock 12 or weaken or melt the feedstock 12 and cause the feedstock 12 to buckle and jam the extrusion system 10. The insulative sleeve 56 may be disposed around a portion of or the entirety of the feed line 38. When the insulative sleeve 56 is only around a portion of the feed line 38, the insulative sleeve 56 may be around a portion of the feed line 38 near or adjacent the print head end 44 of the feed line 38. The feedstock 12 is most likely to melt or weaken in the feed line 38 nearer to the print head 18 because the print head 18 generates a significant amount of heat when melting the feedstock 12, which in turn heats the area surrounding the print head 18 including the portion of the feed line 38 near the print head 18. Thus, having the insulative sleeve 56 around a portion of the feed line 38 adjacent to the print head end 44 is advantageous because it prevents weakening or melting of the feedstock 12 caused by heat given off by the print head 18.

[0051] When the 3D printer 14 includes a build chamber 20, a significant portion of the heat generated by the print head 18 may be retained in and heat the build chamber 20. In such embodiments, the feedstock 12 may be most likely to melt or weaken in the portion of the feed line 38 disposed within the build chamber 20. Thus, when the 3D printer 14 includes a build chamber 20, the insulative sleeve 56 may be disposed around a section of or the entire portion of the feed line 38 extending between the exterior wall of the build chamber 20 and the print head end 44 of the feed line 38. [0052] The insulative sleeve 56 may be heat resistant (i.e., does not bum, melt, or otherwise degrade when exposed to high temperatures) to withstand the temperature it is exposed to during 3D printing. 3D printers 14 typically operate in the range of 200 °F to 1000 °F. Metal 3D printers 14 may even operate in ranges that exceed 1000 °F. The insulative sleeve 56 should be able to withstand temperatures of about 200 °F to about 1000 °F depending on the temperatures at which the 3D printer 14 will be operated. For example, the insulative sleeve 56 may be heat resistant up to a temperature of about 200 °F, about 300 °F, about 400 °F, about 500 °F, about 600 °F, about 700 °F, about 800 °F, about 900 °F, about 1000 °F, or about 1100 °F. [0053] The insulative sleeve 56 may be insulated to reduce the transfer of heat to the feedstock 12 through the feed line 38. The insulative sleeve 56 may have an R-value (in units of °F-ft²-h/BTU) of 0.1 or greater, 0.25 or greater, 0.5 or greater, 1 or greater, 2.5 or greater, 4 or greater, 5 or greater, 7 or greater, 10 or greater, 15 or greater, 20 or greater, 30 or greater, or 40 or greater. In some embodiments, the R-value of the insulative sleeve 56 ranges from about 2 to about 5, about 4 to about 7, or about 6 to about 10. In some embodiments, the R-value of the insulative sleeve 56 may be sufficient to limit the flow rate of heat into the feed line 38 through the insulative sleeve 56 to less than about 1 BTU/hr, less than about 0.75 BTU/hr, or less than about 0.5 BTU/hr across the surface area of the insulative sleeve 56 when the temperature around the insulative sleeve 56 is 800 °F.

[0054] The insulative sleeve 56 may include an insulation layer 58 made from flexible, heat- resistant, and insulative materials. Materials suitable for use in the insulation layer 58 of the insulative sleeve 56 include but are not limited to ceramics, such as alumina, alumina-zirconia, alumina oxide, zirconia MgO, aluminum nitride, silicon carbide, silicon nitride, quartz, and glass; mineral wools, such as rock wool or slag wool; polymers, such as cellulose, polyurethane, polystyrene, polyimides, polyacetals, and polycarbonates; and combinations thereof, such as fiberglass. For example, the insulation layer 58 may include alumina oxide ceramic fiber. The insulation layer 58 may be wrapped around the feed line 38 to form the insulative sleeve 56. The insulation layer 58 may be wrapped around the feed line 38 in a helical pattern. In some embodiments, the insulative sleeve 56 may include two, three, four, or more layers wrapped around the feed line 38. When the insulative sleeve 56 includes multiple insulation layers 58, the insulation layers 58 may be formed from the same or different materials. For example, the insulative sleeve 56 may comprise at least two insulation layers 58 formed from at least two different materials. [0055] The insulative sleeve 56 may also include components for securing the insulation layer 58 around the feed line 38. In some embodiments, one or more metallic wires (not shown) may be wrapped around the insulation layer(s) 58 to secure the insulation layer(s) 58 to the feed line 38. The metallic wires may be wrapped around the insulation layer 58 in a helical pattern. In place of or in addition to the metallic wires, an outer layer 60 may be placed around the insulative sleeve 56 to hold the insulative sleeve 56 together. The outer layer 60 may be a tube formed from a flexible, expandable material, such as woven fiberglass strands, and configured to slide over the insulation layer(s) 58 and/or the metallic wires when the outer layer is compressed and to tighten to secure the flexible insulation and/or metallic wires when the outer layer is elongated. The outer layer 60 may also be heat resistant. For example, the outer layer

60 may be heat resistant up to a temperature of about 200 °F, about 300 °F, about 400 °F, about 500 °F, about 600 °F, about 700 °F, about 800 °F, about 900 °F, about 1000 °F, or about 1100 °F. The outer layer 60 may be formed from heat-resistant materials including but not limited to metals (including alloys), such as iron, nickel, lead, steel, stainless steel, and bronze; ceramics, such as alumina, alumina-zirconia, composites, zirconia MgO, aluminum nitride, silicon carbide, silicon nitride, quartz, and glass; mineral wools, such as rock wool or slag wool; heat resistant polymers, such as polyimides; and combinations thereof, such as fiberglass.

[0056] In some embodiments, the insulative sleeve 56 may include fasteners 62, such as hose clamps, to secure the insulative sleeve 56 around the feed line 38. The fasteners 62 may provide additional rigidity at the ends of the insulative sleeve 56. In embodiments including the fasteners 62, the insulative sleeve 56 may include a first end 64 around which a first fastener 62 is secured and a second end 66 opposite the first end 64 and around which a second fastener

62 is secured. [0057] Throughout the specification and claims, the following terms take at least the meanings explicitly associated herein, unless the context dictates otherwise. The meanings identified below do not necessarily limit the terms, but merely provide illustrative examples for the terms. The meaning of “a,” “an,” and “the” may include plural references, and the meaning of “in” may include “in” and “on.” The phrase “in one embodiment,” as used herein does not necessarily refer to the same embodiment, although it may.

[0058] Although embodiments of the present invention have been described in detail, it will be understood by those skilled in the art that various modifications can be made therein without departing from the spirit and scope of the invention as set forth in the appended claims. [0059] This written description uses examples to disclose the invention and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

[0060] It will be understood that the particular embodiments described herein are shown by way of illustration and not as limitations of the invention. The principal features of this invention may be employed in various embodiments without departing from the scope of the invention. Those of ordinary skill in the art will recognize numerous equivalents to the specific procedures described herein. Such equivalents are considered to be within the scope of this invention and are covered by the claims.

[0061] All of the compositions and/or methods disclosed and claimed herein may be made and/or executed without undue experimentation in light of the present disclosure. While the compositions and methods of this invention have been described in terms of the embodiments included herein, it will be apparent to those of ordinary skill in the art that variations may be applied to the compositions and/or methods and in the steps or in the sequence of steps of the method described herein without departing from the concept, spirit, and scope of the invention. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope, and concept of the invention as defined by the appended claims.

[0062] The previous detailed description has been provided for the purposes of illustration and description. Thus, although there have been described particular embodiments of a new and useful invention, it is not intended that such references be construed as limitations upon the scope of this disclosure except as set forth in the following claims.

Claims

CLAIMS What is claimed is:

1. An extrusion system for providing a wire feedstock to a print head of a 3D printer, the extrusion system comprising: an extruder assembly configured to drive the wire feedstock into the print head; and a feed line defined by at least one extrusion tube, the feed line including: an extruder end secured to and configured to receive the wire feedstock from the extruder assembly, a print head end opposite the extruder end and configured to secure to and provide the wire feedstock to the print head, and an insulative sleeve disposed around the feed line.

2. The extrusion system of claim 1 , wherein the insulative sleeve is heat resistant up to a temperature of 700 °F.

3. The extrusion system of claim 1, wherein the insulative sleeve limits a flow rate of heat into the feed line through the insulative sleeve to less than 1 BTU/hr at 800 °F.

4. The extrusion system of claim 1 , wherein the insulative sleeve comprises at least two insulation layers formed from at least two different materials.

5. The extrusion system of claim 1 , wherein the insulative sleeve comprises alumina oxide ceramic fiber.

6. The extrusion system of claim 1, wherein the insulative sleeve comprises a flexible insulation layer that is helically wrapped around the feed line and one or more metallic wires that are helically wrapped around the insulation layer.

7. The extrusion system of claim 6, wherein the insulative sleeve comprises a flexible, expandable outer layer configured to slide over the insulation layer and one or more wires when the outer layer is compressed and to tighten to secure the insulation layer and one or more wires.

8. The extrusion system of claim 7, further comprising a first fastener and a second fastener, wherein the insulative sleeve comprises a first end and a second end opposite the first end, and wherein the first fastener is secured around the insulative sleeve first end and the second fastener is secured around the insulative sleeve second end.

9. The extrusion system of claim 1 , wherein the at least one extrusion tube is a low-friction extrusion tube.

10. The extrusion system of claim 9, wherein the at least one extrusion tube comprises Teflon.

11. The extrusion system of claim 1, wherein the feed line further comprises: a first extrusion tube adjacent the extruder end; a second extrusion tube adjacent the print head end; and a three-way connector including a feedstock inlet connected to the first extrusion tube, a feedstock outlet connected to the second extrusion tube, and a shielding gas inlet configured to receive shielding gas from a shielding gas source.

12. The extrusion system of claim 1, wherein the extruder assembly comprises: a base; a drive roller rotatably attached to the base; a motor connected to and configured to rotate the drive roller; and an idler block pivotally connected to the base and comprising a clutch roller rotatably attached to the idler block, wherein the idler block is configured to pivot to move the clutch roller between a feed position in which the clutch roller compresses the wire feedstock against the drive roller such that rotation of the drive roller by the motor drives the wire feedstock into the feed line and an idle position in which the clutch roller and drive roller are spaced apart such that rotation of the drive roller by the motor does not drive the wire feedstock into the feed line.

13. The extrusion system of claim 12, wherein the idler block comprises an inlet duct for receiving the wire feedstock, wherein the base comprises a feed block secured to the feed line and including an outlet duct, wherein the outlet duct is aligned with the inlet duct and the feed line to allow the wire feedstock to pass from the inlet duct through the outlet duct into the feed line.

14. A 3D printer for forming a 3D object from a wire feedstock, the 3D printer comprising: a frame; a print head connected to the frame and configured to melt and deposit the wire feedstock to form the 3D object; and an extrusion system for providing the wire feedstock to the print head, the extrusion system including: an extruder assembly secured to the frame and configured to drive the wire feedstock into the print head; and a feed line defined by at least one extrusion tube, the feed line including: an extruder end secured to and configured to receive the wire feedstock from the extruder assembly, a print head end opposite the extruder end and configured to secure to and provide the wire feedstock to the print head, and an insulative sleeve disposed around the feed line.

15. The 3D printer of claim 14, wherein the print head end is secured to the print head by a fitting that is a high-temperature compression fitting or push-to-connect fitting.

16. The 3D printer of claim 15, further comprising a support bracket secured to the feed line adjacent the fitting.

17. The 3D printer of claim 14, further comprising an enclosed build chamber having an exterior wall, wherein the extruder assembly is disposed external to the build chamber and the print head is disposed within the build chamber, and wherein the feed line extends from the extruder assembly through the exterior wall to the print head.

18. The 3D printer of claim 17, wherein the insulative sleeve is disposed around the feed line between the exterior wall and the print head end.

19. The 3D printer of claim 14, further comprising a shielding gas source for providing shielding gas to the extrusion system, wherein the feed line comprises a first extrusion tube adjacent the extruder end, a second extrusion tube adjacent the print head end, and a three-way connector including a feedstock inlet connected to the first extrusion tube, a feedstock outlet connected to the second extrusion tube, and a shielding gas inlet configured to receive shielding gas from the shielding gas source.

20. The 3D printer of claim 14, wherein the wire feedstock has an outer diameter, wherein the at least one extrusion tube has an inner diameter, and wherein a difference in the outer diameter of the wire feedstock and the inner diameter of the tube is between about 0.010 inches and 0.050 inches.