WO2016187106A1

WO2016187106A1 - Apparatus and method for high temperature 3d printing

Info

Publication number: WO2016187106A1
Application number: PCT/US2016/032675
Authority: WO
Inventors: Jennifer A. Lewis; Kundan CHAUDHARY; Thomas J. OBER
Original assignee: President And Fellows Of Harvard College
Priority date: 2015-05-19
Filing date: 2016-05-16
Publication date: 2016-11-24

Abstract

An apparatus for high-temperature 3D printing comprises a modular printhead including a removable nozzle secured to the printhead. The removable nozzle comprises an outlet for passage of a flowable material therethrough and is at least partially surrounded by a heat source. An insulating sheath surrounds the heat source and the removable nozzle. A method of high-temperature printing comprises heating a multicomponent material above a transition temperature thereof to form a flowable material in a nozzle having an outlet. The flowable material passes through the outlet while the nozzle moves relative to an underlying substrate. The flowable material is deposited in a predetermined pattern on the substrate to form a continuous filament comprising a solidified material that includes a first phase and a second phase.

Description

APPARATUS AND METHOD FOR HIGH TEMPERATURE 3D PRINTING

RELATED APPLICATION

[0001] The present patent document claims the benefit of priority under 35 U.S.C. 1 19(e) to U.S. Provisional Patent Application No. 62/163,554, filed on May 19, 2015, and hereby incorporated by reference in its entirety.

TECH N ICAL FI ELD

[0002] The present disclosure is related generally to three-dimensional (3D) printing and more particularly 3D printing at elevated temperatures.

FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0003] This invention was made with government support under contract number FA9550- 12- 1-0471 awarded by the Air Force Office of Scientific Research (AFOSR). The government has certain rights in the invention.

BRI EF SU MMARY

[0004] An apparatus for high-temperature 3D printing comprises a modular printhead including a removable nozzle secured to the printhead. The removable nozzle comprises an outlet for passage of a flowable material therethrough and is at least partially surrounded by a heat source. An insulating sheath surrounds the heat source and the removable nozzle.

[0005] A method of high-temperature printing comprises, according to one embodiment, heating a material in particulate form above a transition temperature thereof to form a flowable material in a nozzle having an outlet. The flowable material passes through the outlet while the nozzle moves relative to an underlying substrate. The flowable material is deposited in a predetermined pattern on the substrate to form a continuous filament comprising a solidified material.

[0006] A method of high-temperature printing comprises, according to another embodiment, heating a multicomponent material above a transition temperature thereof to form a flowable material in a nozzle having an outlet. The flowable material passes through the outlet while the nozzle moves relative to an underlying substrate. The flowable material is deposited in a predetermined pattern on the substrate to form a continuous filament comprising a solidified material that includes a first phase and a second phase.

[0007] The terms "comprising," "including," and "having" are used interchangeably throughout this disclosure as open-ended terms to refer to the recited elements (or steps) without excluding unrecited elements (or steps).

BRI EF DESCRI PTION OF TH E DRAWINGS

[0008] FIGs. 1 A-1 B show an apparatus for high temperature 3D printing that includes a modular printhead comprising a removable nozzle.

[0009] FIGs. 1 C-1 D show additional views of the removable nozzle both attached to (FIG. 1 C) and removed from (FIG. 1 D) the modular printhead.

[0010] FIG. 1 E shows a cross-sectional schematic of the modular printhead.

[0011] FIG. 2A show optical image of the printed structure. FIGs. 2B-2C show scanning electron microscope (SEM) images (cross-sectional and top views) of continuous filaments printed from a eutectic material (AgCI-KCI).

[0012] FIG. 3A is a schematic of an exemplary continuous filament having a lamellar structure and FIGs. 3B-3D show different views of a continuous filament printed from AgCI-KCI.

[0013] FIGs. 4A-4C show SEM images of lamellar structure formation in 3D printed filaments comprising AgCI-KCI as a function of print speed (U).

[0014] FIG. 4D shows lamellar spacing as a function of print speed at three different substrate temperatures.

[0015] FIG. 5A shows lamellar spacing versus nozzle height using data from AgCI-KCI printed filaments. [0016] FIG. 5B shows filament thickness versus nozzle height using data from AgCI-KCI printed filaments.

[0017] FIG. 6A shows a cross-sectional SEM image of a multilayer printed structure (10 filament layers) formed from AgCI-KCI at a print speed of 7.5 cm/s.

[0018] FIG. 6B shows lamellar spacing as a function of layer number for the multilayer printed structure of FIG. 6A.

[0019] FIGs. 7A-7C show continuous filaments printed at a nozzle temperature of 200°C from Bi-Sn solder, polylactic acid (PLA) and Isomalt, respectively.

DETAI LED DESCRIPTION

[0020] An apparatus for high-temperature 3D printing and a method of high-temperature 3D printing are described in this disclosure. The apparatus and method may enable multicomponent materials to be 3D printed at elevated temperatures while controlling the size, spacing, orientation and/or morphology of individual phases that form upon solidification.

[0021] Referring to FIGs. 1A-1 E, an apparatus 100 for high-temperature 3D printing includes a modular printhead 105 comprising a removable nozzle 1 10 that is adjacent to or at least partially surrounded by a heat source 1 15. The removable nozzle 1 10 is secured to the printhead 105 and includes an outlet 120 for passage of a flowable material therethrough. An insulating sheath 125 at least partially surrounds the heat source 1 15 and the removable nozzle 1 10 to minimize heat loss to the surrounding environment during printing. The removable nozzle 1 10 is secured to the printhead 105 for printing, such that the printhead 105 and nozzle 1 10 may move as a unit during printing, and then the nozzle 1 10 may be removed after printing, if desired (e.g., to swap for a nozzle of a different diameter). Thus, the removable nozzle 1 10 may be described as disposable and/or may be fabricated from an inexpensive material. [0022] The modular printhead 105 may further include a thermally conductive barrel 130 positioned between the heat source 1 15 and the removable nozzle 1 10 to act as a heat spreader during printing. The barrel 130 may be machined from a metal or alloy such as stainless steel. The heat source 1 15 may comprise an electrically conductive coil 135, such as a copper coil, configured for passage of an electrical current therethrough to effect resistive heating. In the example of FIG. 1A, the conductive coil 135 is helically wound about a longitudinal axis of the removable nozzle. More specifically, the conductive coil 135 may be wound about and in contact with the thermally conductive barrel 130. The insulating sheath 125 that at least partially surrounds both the heat source 1 15 and the removable nozzle 1 10 may comprise a ceramic, such as refractory oxide (e.g., AI₂O3 or ZrO₂) or a non-oxide (e.g., AIN, Si₃N₄).

[0023] The modular printhead 105 may be attached to a standard CNC (computer numerical controlled) stage 140 to facilitate translational motion of the nozzle in the x, y and/or z directions. The printhead 105 may also be rotated about the x- y- and/or z-axes for 6-degree of freedom movement. Alternatively, the printhead 105 may remain stationary during printing and an underlying substrate 145 may be moved, or both the nozzle 1 10 and the substrate 145 may be moved to effect relative motion therebetween.

[0024] The removable nozzle may be made of one or more heat-resistant materials having a glass transition temperature or melting temperature high enough for the removable nozzle to maintain integrity as the flowable material passes through at elevated temperatures. For example, the melting or glass transition temperature of the heat-resistant material may be at least about 300°C, at least about 400°C, or at least about 500°C. Suitable heat-resistant (or refractory) materials may include metals or alloys such as stainless steel, ceramics such as alumina, and/or silica-based glasses such as soda-lime glass, borosilicate glass (e.g., Pyrex), quartz and/or Vycor. As will be discussed further below, the printing process is typically carried out at a nozzle temperature in the range of from about 150°C to about 650°C, and more typically from 150°C to about 500°C, although other nozzle

temperatures above and below these ranges are possible. The particular temperature selected may depend on the composition of the material being printed as well as the properties of the removable nozzle.

[0025] The removable nozzle may have an inner diameter of from about 1 micron to about 10 mm in size, and more typically from about 50 microns to about 1 mm. Prior to insertion of the removable nozzle into the modular printhead, the diameter of the removable nozzle may be determined by a thermally-aided pulling process applied to a nozzle preform, as described further below. The size of the nozzle may be selected depending on the desired filament diameter. Depending on the injection pressure and the nozzle translation speed, as discussed further below, the continuous filament deposited on the substrate may have a diameter ranging from about 1 micron to about 10 mm, and more typically from about 50 microns to about 1 mm.

[0026] The modular printhead shown in FIG. 1 A may be employed for high temperature 3D printing of any of a number of single- or

multicomponent materials that are flowable at the elevated temperature at which printing is carried out. For example, suitable single-component materials may include low melting-point metals (e.g., Bi, Cd, Ga, In, Pb, Sn or Se) or polymers (e.g., thermoplastic polymers such as polylactic acid (PLA), poly(methyl methacrylate) (PMMA), acrylonitrile butadiene styrene (ABS) or a polyamide). Suitable multicomponent materials may include copolymers, such as those described below, or low melting point alloys, such as those containing at least one of the following elements: Bi, Cd, Ga, In, Pb, Sn, and Se. Other suitable multicomponent materials may include low melting point glasses, such as leaded glass, lead silicate glass, or borosilicate glass.

[0027] 3D printed structures formed from multicomponent materials, such as eutectic or copolymer systems, may have a lamellar structure of alternating solid phases. The lamellae may be aligned parallel to the direction of printing and the lamellar spacing can be controlled by varying parameters such as print speed, substrate temperature, and nozzle height, as described further below. Such printed structures may find use as metamaterials in optics and other applications.

[0028] The newly-developed high temperature 3D printing method entails, according to one embodiment, heating a material in particulate form above a transition temperature thereof to form a flowable material (e.g., a molten material) in a nozzle 1 10 having an outlet 120, such as that shown in FIGs. 1A and 1 B. The flowable material passes through the outlet 120 while the nozzle 1 10 moves relative to an underlying substrate 145. The flowable material is deposited in a predetermined pattern on the substrate 145 to form a continuous filament 150 comprising a solidified material. The material of this embodiment may be a single-component material or a multicomponent material, as described above. The material in particulate form may comprise particles having an average size of from about 10 nm to about 500 microns. The material may be introduced into the nozzle in a batch or continuous process, and may take the form of a powder or a slurry comprising the particles.

[0029] According to another embodiment, the high temperature printing method may entail heating a multicomponent material above a transition temperature thereof to form a flowable material (e.g., a molten material) in a nozzle 1 10 comprising an outlet 120, such as that shown in FIGs. 1A and 1 B. The flowable material passes through the outlet 120 while the nozzle moves relative to an underlying substrate 145. The flowable material is deposited in a predetermined pattern on the substrate 145 to form a continuous filament 150 comprising a solidified material having a first phase and a second phase. As in the previous embodiment, the multicomponent material may be in particulate form prior to heating and may include particles having an average size of from about 10 nm to about 500 microns. The multicomponent material may be introduced into the nozzle in a batch or continuous process, and may take the form of a powder or slurry comprising the particles.

[0030] The single- or multicomponent material of the above-described embodiments may include particles having an average size of at least about 100 nm, at least about 500 nm, at least about 1 micron, at least about 10 microns, or at least about 100 microns. Typically, the particles have an average size of about 500 microns or less, about 300 microns or less, or about 100 microns or less.

[0031] The nozzle employed in the high temperature 3D printing method may be the removable nozzle described above that can be secured to a modular printhead for printing and then removed after printing, if desired.

[0032] In order to heat the single- or multicomponent material above the transition temperature for printing, the nozzle may be heated to a

temperature of from about 150°C to about 650°C. A heat source may be integrated with the nozzle, or with a modular printhead that contains the nozzle, so that the heating may be carried out continuously as the nozzle moves with respect to the substrate. For example, the heat source may comprise a conductive coil which is wound about a longitudinal axis of the nozzle for resistive heating, as described above.

[0033] The substrate may also be heated to reduce heat loss from the outlet of the nozzle to the substrate and surrounding environment during printing. The substrate may be heated to a temperature above room temperature and below the transition temperature of the multicomponent material to ensure that solidification occurs upon contact with the substrate. In one example, the substrate may be heated to a substrate temperature of least about 50°C, at least about 100°C, at least about 150°C, or at least about 200°C, as shown for example in FIG. 1 E. Typically, the substrate temperature is no greater than about 300°C, or no greater than about 250°C.

[0034] The flowable material may be forced through the outlet of the nozzle at an applied pressure of from about 1 psi to about 200 psi, from about 1 psi to about 100 psi, or from about 2 psi to about 80 psi. In some cases, only modest applied pressures of from about 1 psi to about 10 psi, or from about 1 psi to about 5 psi, are required since the flowable material may be a low-viscosity, Newtonian fluid. The pressure during extrusion may be constant or it may be varied. By using alternative pressure sources, pressures of higher than 100 psi or 200 psi and/or less than 1 psi may be applied during printing. Typically, the outlet of the nozzle is maintained at a distance above the substrate from about 10 microns to about 300 microns, or from about 30 microns to about 100 microns.

[0035] The nozzle may move relative to the substrate at a print speed as high as about 1 m/s (e.g., from about 1 cm/s to about 1 m/s). More typically the print speed is in the range of from about 0.1 cm/s to about 50 cm/s, from about 0.1 cm/s to about 10 cm/s, or from about 1 cm/s to about 5 cm/s. The print speed and other process parameters may influence the solidified microstructure of the continuous filament formed on the substrate.

[0036] When a multicomponent material is printed, the solidified material may have a lamellar structure comprising lamellae of the first phase alternating with lamellae of the second phase. Such a lamellar structure may result when, for example, the multicomponent material is a eutectic material at a eutectic composition thereof, and when the transition temperature is a eutectic temperature. As shown below, the spacing between the lamellae of the first phase and a spacing between the lamellae of the second phase may (a) decrease as print speed increases and/or (b) increase as substrate temperature increases.

[0037] As would be understood by one of ordinary skill in the art, in a binary eutectic system, a liquid phase and two solid phases exist in equilibrium at the eutectic composition and eutectic temperature. Upon cooling through the eutectic temperature, a solid material is formed comprising the two solid phases. Eutectic systems that may be suitable for high temperature 3D printing generally have a eutectic temperature (or eutectic point) of less than 750°C, less than 600°C, or less than about 450°C. For example, the eutectic system may be selected from among NaF- LiF, NaF-NaCI, LiF-KCI, AgCI-KCI, Bi-Sn, SCN-camphor. Other exemplary eutectic systems that may be suitable for high temperature 3D printing, including eutectic salt systems, can be found in George J. Janz, et al., Physical Properties Data Compilations Relevant to Energy Storage: I.

Molten Salts: Eutectic Data, Nat. Stand. Ref. Data Ser., Nat. Bur. Stand. (U.S.), 61 , Part I, March, 1978, which is hereby incorporated by reference.

[0038] A lamellar structure may also be obtained during printing when the multicomponent material system comprises a copolymer, such as a block copolymer. In this case, the transition temperature may be a glass transition temperature of the copolymer. Suitable copolymers may include, for example, poly(L-lactide)(PLLA) and polyvinyl acetate) (PVAc) in/with hexamethylbenzene (HMB), or polystyrene-block-polyisoprene (PS-b-PI) with benzoic acid.

EXAMPLES

[0039] To demonstrate high-temperature 3D printing of a multicomponent system, the eutectic AgCI-KCI system, which has an eutectic temperature, T_E, of 319 C, is investigated. This system readily forms lamellar

architectures from which the KCI phase can be selectively etched using a polar solvent, if desired.

[0040] In addition to the AgCI-KCI eutectic salt system, a Bi-Sn solder, a polymer (polylactic acid) and a sugar substitute (Isomalt) are 3D printed at elevated temperatures.

Eutectic Ink Preparation

[0041] AgCI and KCI are mixed at a ratio of 70:30 mol.%, corresponding to the eutectic composition, and heated at a temperature of 500°C for two hours to ensure compositional homogeneity. The melt is then cooled, and a mortar and pestle are used to form a powder, which may then be introduced into the removable nozzle to form the flowable material for high temperature 3D printing. Preparation of Removable Nozzle

[0042] Glass Nozzle with Thicker Walls

[0043] A glass (borosilicate) Pasteur pipet is melted at the tip. Roughly 1 cm of the tip length is in contact with a flame (e.g., from Bunsen burner). The Pasteur pipet is rotated by hand at roughly 1 rotation per second for about 15 s. This method can be easily automated by a rotating stage. The glass is heated above the glass transition temperature and begins to flow, and as a result, the tip in contact with the Bunsen flame tapers off in terms of its inner diameter (ID), but the outer diameter (OD) remains roughly 1 mm. Since the OD is 1 mm, it is difficult to use a laser cutter or a microforge to cut the tip to a certain ID. Thus, sandpaper may be used to polish the tip to the appropriate ID.

[0044] Glass Nozzle with Standard Walls

[0045] A glass Pasteur pipet is melted at the tip. Roughly 1 cm of the tip length is in contact with the flame (e.g., from a Bunsen burner). The molten tip is pulled using a tweezer, which results in a tip with a tapered geometry. The pulling process is monitored with a camera, and the camera's field of view (display on monitor) is calibrated using a graticule. The section of the pulled pipet to cut using a laser is placed in the laser's focal plane/voxel, which is also fixed and centered within the camera's field of view. Sample stage can be moved around to adjust for the position of the inner diameter of the tapered geometry. An exemplary fabricated glass nozzle having a nominal outer diameter (OD) of 300 microns has an average OD, after laser cutting, of 309 ± 14 μηι and an average inner diameter (ID) of 243 ± 21 μηι.

High Temperature 3D Printing of AgCI-KCI

[0046] A custom-built high-temperature printhead with a removable glass nozzle that is heated to T_N =350°C is employed for printing. The eutectic material is prepared as described above and is provided to the removable nozzle in the form of a powder, which forms a flowable (molten) material upon heating above the eutectic temperature. The molten eutectic material is deposited onto a glass substrate held at a temperature, T₀, between 200- 220 C. At elevated temperatures, AgCI-KCI corrodes stainless steel, but remains inert to glass. Only a modest applied pressure (1-3 psi) is required for printing since the molten eutectic material is a low viscosity, Newtonian fluid. The nozzle outlet (or tip) is maintained at a height (G) of 30-100 μηι above the substrate and is translated at speeds ranging from 0.5-10 cm/s, which allows for controlled printing of molten AgCI-KCI to form low-aspect ratio, continuous filaments over large areas, as shown for example in FIGs. 2A-2C.The printed, solidified filaments include lamellar phases oriented perpendicular to the substrate surface and parallel to the printing direction. These lamellar phases may be aligned parallel to the longitudinal axis of the continuous filament, as shown by the schematic of FIG. 3A and the images of FIGs. 3B-3D, which show the microstructure of a printed filament comprising AgCI-KCI. The bottom surface may exhibit a disordered structure due to the rapid solidification of molten AgCI-KCI upon impact with the substrate.

[0047] The control of lamellar orientation and spacing arises from the ability to control the diffusion of solute along the interface in the liquid by controlling parameters such as print speed. Lamellar spacing decreases with increasing print speed. FIGs. 4A-4C show representative lamellar structures at print speeds of 0.5 cm/s, 2.5 cm/s, and 7.5 cm/s, respectively. As the nozzle is translated at higher speeds, the rate of heat energy transferred from the eutectic melt to the substrate increases, leading to a decrease in diffusion length and results in a shorter lamellar spacing. The ratio of the thickness of the eutectic phases in the lamellar structure at different print speeds remain constant, e.g., AgCI:KCI is 0.7:0.3. This ratio is in good agreement with that expected based on the molar ratio of AgCI-KCI of 0.7:0.3 at the eutectic composition.

[0048] As plotted in FIG. 4D, the lamellar spacing decreases with printing speed over the range 0.5-10 cm/s at different substrate temperatures (Γ₀), 200 C, 210 C, and 220 C. Substrate temperature is another important control parameter that may affect the lamellar spacing. Lamellar spacing increases with increasing substrate temperature as the diffusion length increases with decreased temperature gradient between the melt and the substrate during solidification.

[0049] Beyond print speed and substrate temperature, the nozzle height may also influence the lamellar spacing within the printed filaments. The lamellar spacing increases with increasing nozzle height over the range 30- 100 μηι (FIG. 5A). Larger nozzle heights correspond to thicker filaments and lower temperature gradients.

[0050] The process of lamellar structure formation upon eutectic solidification is similar to conventional directional solidification, where a two- component eutectic melt growing at a growth velocity, V, across a

temperature gradient results in a lamellar structure consisting of alternating layers of α-phase (AgCI-rich) and β-phase (KCI-rich). Potassium ions build up in the liquid in front of the growing interface as a-phase solidifies. These excess potassium ions diffuse laterally in the liquid to the β-phase

solidification front. A similar process occurs for the excess silver ions in front of the β-phase regions. High-temperature printing of eutectic inks differs from conventional directional solidification with respect to the large temperature gradients that can be introduced with the growth of the solidification front as the nozzle translates away from the site of deposition during printing. Thermal energy is transferred from the molten ink to the substrate, which may be maintained at temperatures much lower than the eutectic temperature.

[0051] To demonstrate multilayer 3D printing, multilayer filaments were deposited using a multipass printing process (FIG. 6A) where the molten eutectic material is deposited as a continuous filament in a layer-by-layer deposition sequence. In contrast to 3D printing of viscoelastic inks under ambient conditions, these low viscosity, molten eutectic inks can induce melting of the underlying layer(s), making it difficult to control and maintain th e structural integrity of the multilayer printed structure. However, the appropriate conditions were obtained to ensure that multilayer structures could be patterned and epitaxially grown on top on one another. A thin interface is observed between printed layers, which exhibited locally disordered regions due to remelting of the surface underneath and

entrapped pores. As shown in FIG. 6B, the lamellar spacing in different layers remains nearly constant. Hence, this printing method can be used to fabricate lamellar structures of arbitrary thickness, although additional experiments may be needed to eliminate the interfacial zones.

High Temperature 3D Printing of a Bi-Sn Solder

[0052] Bi-Sn eutectic solder was heated to above the eutectic

temperature and 3D printed on an unheated glass substrate at a print speed of 1 cm/s and an applied pressure of 20 psi. A nozzle having an inner diameter of 50 microns was heated to a temperature of about 200°C for printing. Continuous filaments comprising the solder are shown in FIG. 7A.

High Temperature 3D Printing of Polylactic Acid (PLA)

[0053] A polymer (polylactic acid (PLA)) was heated to above the glass transition temperature and 3D printed on an unheated glass substrate at a print speed of 0.5 cm/s and an applied pressure of 80 psi. A nozzle having an inner diameter of 50 microns was heated to a temperature of about 200°C for printing. Continuous filaments comprising the polymer are shown in FIG. 7B.

High Temperature 3D Printing of a Sugar Substitute (Isomalt)

[0054] Isomalt, a sugar substitute, was heated to above a transition temperature and 3D printed on an unheated glass substrate at a print speed of 0.5 cm/s and an applied pressure of 10 psi. A nozzle having an inner diameter of 50 microns was heated to a temperature of about 200°C for printing. Continuous filaments comprising the Isomalt are shown in FIG. 7C. [0055] Although the present invention has been described in

considerable detail with reference to certain embodiments thereof, other embodiments are possible without departing from the present invention. The spirit and scope of the appended claims should not be limited, therefore, to the description of the preferred embodiments contained herein. All embodiments that come within the meaning of the claims, either literally or by equivalence, are intended to be embraced therein.

[0056] Furthermore, the advantages described above are not necessarily the only advantages of the invention, and it is not necessarily expected that all of the described advantages will be achieved with every embodiment of the invention.

Claims

1. An apparatus for high-temperature 3D printing, the apparatus comprising:

a modular printhead comprising:

a removable nozzle secured to the printhead and comprising an outlet for passage of a flowable material therethrough, the removable nozzle being at least partially surrounded by a heat source; and

an insulating sheath surrounding the heat source and the removable nozzle.

2. The apparatus of claim 1 , further comprising a thermally conductive barrel between the heat source and the removable nozzle.

3. The apparatus of claim 1 or 2, wherein the removable nozzle comprises a silica-based glass.

4. The apparatus of any one of claims 1-3, wherein the heat source comprises a conductive coil configured for resistive heating.

5. The apparatus of claim 4, wherein the conductive coil is helically wound about a longitudinal axis of the removable nozzle.

6. The apparatus of any one of claims 1-5, wherein the removable nozzle comprises an inner diameter of from about 50 microns to about 1 mm.

7. The apparatus of any one of claims 1-6, wherein, prior to insertion of the removable nozzle into the modular printhead, an inner diameter of the removable nozzle is determined by a thermally-aided pulling process applied to a nozzle preform.

8. The apparatus of any one of claims 1-7, wherein the removable nozzle is disposable.

9. The apparatus of any one of claims 1-8, wherein the insulating sheath comprises a ceramic.

10. A method of high-temperature printing, the method comprising: heating a material in particulate form above a transition temperature thereof to form a flowable material in a nozzle having an outlet, the flowable material passing through the outlet while the nozzle moves relative to an underlying substrate;

depositing the flowable material in a predetermined pattern on the substrate to form a continuous filament comprising a solidified material.

11. The method of claim 10, wherein the material in particulate form comprises particles having an average size of about 10 nm to about 500 microns.

12. The method of claim 10 or 11 , therein the material in

particulate form is introduced into the nozzle in a batch process.

13. The method of claim 10 or 11 , wherein the material in particulate form is introduced into the nozzle in a continuous process.

14. The method of any one of claims 10-13, wherein the material comprises a multicomponent material, and the solidified material comprises a first phase and a second phase.

15. The method of any one of claims 10-14, wherein the substrate is heated to a substrate temperature below the transition temperature of the material.

16. The method of claim 15, wherein the substrate temperature is from about 50°C to about 300°C.

17. The method of any one of claims 10-16, wherein heating the material comprises heating the nozzle to a temperature in the range of from about 150°C to about 650°C.

18. The method of any one of claims 10-17, wherein the nozzle moves relative to the substrate at a print speed of from about 0.1 cm/s to about 50 cm/s.

19. The method of any one of claims 10-18, wherein the flowable material is forced through the outlet of the nozzle at an applied pressure of from about 1 psi to about 100 psi.

20. A method of high-temperature printing, the method comprising: heating a multicomponent material above a transition temperature thereof to form a flowable material in a nozzle having an outlet, the flowable material passing through the outlet while the nozzle moves relative to an underlying substrate;

depositing the flowable material in a predetermined pattern on the substrate to form a continuous filament comprising a solidified material, wherein the solidified material comprises a first phase and a second phase.

21. The method of claim 20, wherein the solidified material has a lamellar structure comprising lamellae of the first phase alternating with lamellae of the second phase.

22. The method of claim 21 , wherein the lamellae of the first phase and the second phase are substantially aligned with a longitudinal axis of the continuous filament.

23. The method of any one of claims 20-22, wherein the

multicomponent material comprises a eutectic material at a eutectic composition thereof, and the transition temperature is a eutectic

temperature.

24. The method of any one of claims 20-12, wherein the multicomponent material comprises a copolymer, and the transition temperature is a glass transition temperature.

25. The method of any one of claims 20-24, wherein the substrate is heated to a substrate temperature below the transition temperature of the multicomponent material.

26. The method of claim 25, wherein the substrate temperature is from about 50°C to about 300°C.

27. The method of any one of claims 20-26, wherein heating the multicomponent material comprises heating the nozzle to a temperature in the range of from about 150°C to about 650°C.

28. The method of any one of claims 20-27, wherein the nozzle moves relative to the substrate at a print speed of from about 0.1 cm/s to about 50 cm/s.

29. The method of any one of claims 20-28, wherein the flowable material is forced through the outlet of the nozzle at an applied pressure of from about 1 psi to about 100 psi.

30. The method of any one of claims 20-29, wherein a spacing between the lamellae of the first phase and a spacing between the lamellae of the second phase decrease as print speed increases.

31 . The method of any one of claims 20-30, wherein a spacing between the lamellae of the first phase and a spacing between the lamellae of the second phase increase as substrate temperature increases.