Printer jetting mechanism and printer employing printer jetting mechanism

Abstract

To provide a jetting mechanism and a 3D printer that have ability to selectively jet print materials including a wide range of metals and other materials, the ability to jet selectable droplet volumes, and the like.SOLUTION: A three-dimensional printer comprises a plurality of ejector conduits 106 arranged in an array, each ejector conduit comprising a first end 106A positioned to accept a print material, and a second end 106B comprising an ejector nozzle 108. The 3D printer also comprises a plurality of radiant energy sources positionable such that a path of radiant energy emitted from one or more of the radiant energy sources is capable of striking the ejector nozzle of each of the ejector conduits during operation of the 3D printer. The 3D printer further comprises a positioning system for controlling a relative position of the array and a print substrate so as to allow the print substrate to receive the print material jettable from the plurality of ejector conduits during operation of the 3D printer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure is directed to printer jetting mechanisms that can be used in printers used for additive manufacturing (referred to herein as three-dimensional (“3D”) printers). The present disclosure is also directed to methods of jetting printing material, including methods of 3D printing. [Background technology]

[0002] Melting of solid materials, including materials in the form of solid filaments, is commonly used in 3D printing technology. It is well understood that when a phase change or heating of a material occurs, the material generally expands and, in the case of a phase change from solid to liquid, becomes flowable. Printing materials are often melted to allow the material to flow and deposit on a substrate, from which a 3D object is formed. As a specific example, liquid 3D printers for building 3D objects from molten aluminum are known in the art. One such 3D printer is disclosed in U.S. Patent No. 9,616,494. The 3D printer functions by using DC pulses applied by an electromagnetic coil to eject molten aluminum droplets in response. A platen, which targets the droplets, translates to allow the droplets to connect and accumulate, generating the three-dimensional object. However, the molten aluminum droplets ejected from this 3D printer have a diameter of approximately 0.5 mm or greater. This enables high-volume, throughput production of metal parts. However, relatively large droplet sizes can result in undesirable degrees of porosity in the printed 3D object, as well as uneven build surfaces, unwelded droplets, and shape variations during manufacturing, all of which can lead to poor physical properties such as insufficient tensile strength, poor cosmetic appearance issues with the final object, and / or an inability to print objects with very fine detail.

[0003] Therefore, a method and system for improving the quality of three-dimensional objects produced from a three-dimensional printer, such as a liquid metal printer, would represent an advancement in the art. Summary of the Invention

[0004] One embodiment of the present disclosure is directed to a three-dimensional ("3D") printer. The 3D printer includes a plurality of ejector conduits arranged in an array, each of the ejector conduits including a first end positioned to receive printing material, a second end including an ejector nozzle, and a passageway defined by an inner surface of the ejector conduit to allow the printing material to pass through the ejector conduit from the first end to the second end. The 3D printer further includes a plurality of radiant energy sources positionable such that a path of radiant energy emitted from one or more of the plurality of radiant energy sources can strike the ejector nozzle of each of the plurality of ejector conduits during operation of the 3D printer, and a positioning system for controlling the relative position of the array with a printed circuit board in a manner that allows the printed circuit board to receive printing material jettable from the plurality of ejector conduits during operation of the 3D printer.

[0005] Another embodiment of the present disclosure is directed to a printer ejection mechanism including a plurality of ejector conduits arranged in an array, each having a first end configured to receive printing material, a second end including an ejector nozzle, and a passage defined by an inner surface of the ejector conduit for allowing the printing material to pass through the ejector conduit from the first end to the second end. The printer ejection mechanism further includes a plurality of radiant energy sources, the plurality of radiant energy sources being positionable such that a path of radiant energy emitted from one or more of the plurality of radiant energy sources can strike the ejector nozzle of each of the plurality of ejector conduits during operation of the printer ejection mechanism.

[0006] Yet another embodiment of the present disclosure is directed to a three-dimensional ("3D") printer jetting mechanism comprising a plurality of ejector conduits arranged in an array, each ejector conduit comprising a first end positioned to receive printing material, a second end comprising an ejector nozzle, and a passageway defined by an inner surface of the ejector conduit for allowing the printing material to pass through the ejector conduit from the first end to the second end, the ejector nozzle configured to transmit energy from a radiant energy source to a portion of the passageway within the ejector nozzle.

[0007] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present teachings, as claimed. [Brief explanation of the drawings]

[0008] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present teachings and, together with the description, serve to explain the principles of the present teachings. [Figure 1] 1 illustrates an example of a printer jetting mechanism, according to one embodiment of the present disclosure. [Figure 2] 1 illustrates a top view of a printer jetting mechanism, according to one embodiment of the present disclosure. [Figure 3] 1 illustrates a bottom view of an ejector nozzle having an inner width (e.g., diameter) di according to one embodiment of the present disclosure. [Figure 4] 1 illustrates a top view of a printer ejection mechanism comprising rows of staggered ejector conduits according to one embodiment of the present disclosure. [Figure 5A] 1 illustrates a schematic cross-sectional view of an ejector conduit having printing material therein that may be used in the printer jetting mechanisms described herein, according to one embodiment of the present disclosure. [Figure 5B] 5B illustrates a schematic cross-sectional view of the ejector conduit of FIG. 5A after vaporization of a portion of the printing material and ejection of another portion of the printing material below the vaporized portion, according to one embodiment of the present disclosure. [Figure 6] 1 illustrates a schematic cross-sectional view of an ejector conduit with a vent, according to one embodiment of the present disclosure. [Figure 7A] 1 illustrates a schematic bottom view of an ejector nozzle with multiple vents, according to one embodiment of the present disclosure. [Figure 7B] 7B illustrates a schematic cross-sectional view of a portion of the ejector conduit 106 along line AA including the ejector nozzle of FIG. 7A, according to one embodiment of the present disclosure. [Figure 8] FIG. 1 is a block diagram of a 3D printer according to one embodiment of the present disclosure. [Figure 9] 1 is a flow diagram of a method for ejecting printing material from a printer ejection mechanism according to one embodiment of the present disclosure. [Figure 10] FIG. 1 illustrates a schematic side view of a printer jetting mechanism with multiple ejector conduits that simultaneously eject droplets to print a 3D object on a printed circuit board, according to one embodiment of the present disclosure. [Figure 11] FIG. 1 is a schematic diagram of a 3D printer according to one embodiment of the present disclosure.

[0009] It should be noted that some details of these figures have been simplified and strict structural accuracy, detail, and scale are not maintained, but rather are drawn to facilitate understanding of the embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0010] Reference will now be made in detail to embodiments of the present teachings, examples of which are illustrated in the accompanying drawings, wherein like reference numerals are used to designate the same elements throughout. In the following description, reference is made to the accompanying drawings, which form a part hereof, and in which are shown by way of illustration specific exemplary embodiments in which the present teachings may be practiced. Accordingly, the following description is by way of example only.

[0011] The present disclosure is directed to a printer jetting mechanism comprising a plurality of ejector conduits arranged in a jet array and a 3D printer using the printer jetting mechanism. Methods of using such jetting mechanisms to jet printing material are also disclosed. The printer jetting mechanism is designed to use radiant energy-induced expansion of the printing material as a force for jetting, as described in more detail herein. The jetting mechanisms, 3D printers, and printing methods disclosed herein can provide one or more of the following advantages: the ability to selectively jet printing materials, including a wide range of metals and other materials; the ability to jet selectable drop volumes; the ability to jet small drop sizes enabling printing of fine and / or selectable feature sizes; and the ability to print at relatively high throughput.

[0012] Printer injection mechanism FIG. 1 illustrates an example of a printer jetting mechanism 100 according to one embodiment of the present disclosure. The printer jetting mechanism 100 optionally includes a feeder mechanism 102 for advancing a printing material 104 to be printed. An exemplary printing material 104 is a preformed wire of a selected alloy, or other materials as discussed in more detail below. A plurality of ejector conduits 106 are arranged in an array 107. Each ejector conduit 106 includes a first end 106A positioned to receive the printing material 104 from the feeder mechanism 102. The second end 106B includes an ejector nozzle 108. FIG. 2 illustrates a top view of the printer jetting mechanism 100. A passage 106C defined by the inner surface of each of the ejector conduits 106 allows the printing material 104 to pass through the ejector conduit 106 from the first end 106A to the second end 106B. As also illustrated in FIG. 2 , the printer jetting mechanism further includes multiple radiant energy sources 110 for emitting radiant energy 112. The multiple radiant energy sources 110 can be arranged such that, during operation of the printer jetting mechanism 100, a path of radiant energy 112 emitted from one or more of the multiple radiant energy sources 110 can strike the ejector nozzle 108 of each of the multiple ejector conduits 106. Referring to FIG. 2 , the multiple radiant energy sources 110, which can be lasers (e.g., laser pixels in a laser array) or any other source of radiant energy suitable for providing thermal energy to the ejector nozzles 108, are switched on or off as desired to heat the printing material 104 in the ejector nozzles 108 to achieve rapid expansion of the printing material. The rapid expansion of the printing material can include a phase change (e.g., melting) of the printing material or can be accomplished by expansion of the material in a single phase. Examples of lasers that can be used as the radiant energy source 110 include fiber laser arrays or scanned and modulated lasers that can provide suitable pulses of radiation for the desired expansion of the printed material and are well known in the art.

[0013] The radiant energy source 110 may be selected to emit radiation at any wavelength suitable for providing the desired thermal energy to achieve expansion of the print material. The particular wavelength used will depend, among other things, on the type of print material being used. Examples of suitable wavelengths range from ultraviolet ("UV") wavelengths to near-infrared ("NIR") wavelengths, such as from about 300 nm to about 1500 nm. As another example, the wavelength ranges from about 600 nm to about 1100 nm.

[0014] Referring to FIG. 3, the ejector nozzle 108 has an inner width (e.g., inner diameter) d that ranges in size from about 10 micrometers to about 1000 micrometers, from about 20 micrometers to about 500 micrometers, from about 50 micrometers to about 200 micrometers, or about 100 micrometers. i In one embodiment, d i is in the size range of about 10 micrometers to about 100 micrometers, for example, about 10 micrometers to about 50 micrometers, or about 10 micrometers to about 25 micrometers. i It should be noted that although illustrated as being a circle having a diameter of 1 / 2, any other cross-sectional shape can be used, such as, for example, a rectangle or other polygon, an ellipse, or other shape. The interior width of a cross-sectional shape other than a circle is the widest cross-sectional dimension (e.g., the diagonal between two opposite vertices of a square cross-section) where the cross-section lies in a plane perpendicular in all directions to the longitudinal axis "1" (FIG. 1) of passage 106C at the point where the cross-section intersects passage 106C (e.g., d i )d, such as when the value of i If there is more than one possible value for d i is the possible d for the ejector nozzle 108 i The "internal width" is often referred to herein as the "internal diameter," although the terms "diameter" or "internal diameter" can be interchanged with "internal width" when discussing the internal diameter of an ejector nozzle throughout this disclosure.

[0015] The ejector nozzle 108 may be an end portion of the ejector conduit 106 that is positioned for exposure to radiant energy 112 from the radiant energy source 110 during operation of the printer ejection mechanism 100. The length of the ejector nozzle 108 may be, for example, in the range of about 1 to about 10 times its internal width (e.g., internal diameter). The design and materials of the ejector nozzle 108 may be the same as or different from the remainder of the ejector conduit 106.

[0016] In one embodiment, the passageway 106C of the ejector conduit 106 has a second inner width at the first end 106A, the second inner width being smaller than the inner width d of the ejector nozzle 108 to allow the passageway 106C to fit closely around the printing material in the ejector nozzle 108 while allowing the printing material to be easily threaded into the first end 106A. i In one embodiment, the passageway 106C gradually tapers from the second inner width to the inner width of the ejector nozzle 108 to prevent printing material 104 in the form of a solid filament from getting caught in and / or undesirably blocking the passageway 106C.

[0017] The feeder mechanism 102 can be any suitable mechanical system, pressure-driven system, or other system capable of delivering the printing material 104 to the ejector conduit 106. The feeder mechanism can include one or more pumps, actuators, or combinations thereof, which can function as a mover 102a (FIG. 11) to move the printing material 104. Examples of suitable actuators include electric motors, piezoelectric motors, inchworm actuators, hydraulic actuators, and pneumatic actuators. The type of feeder mechanism 102 used will depend on the type of printing material 104 used. In one embodiment, the printing material 104 includes multiple filaments, and the feeder mechanism 102 is a mechanism for advancing the multiple filaments. For purposes of this disclosure, the term “filament” is defined to include both solid, wire-like filaments or liquid filaments, such as liquid-filled capillaries or other liquid-filled conduits. Examples of feeder mechanisms for solid filaments include spool feeders and inchworm actuators, which are well known in the art. As will be appreciated by those skilled in the art, other feeder devices for ratcheting or otherwise advancing solid printing material 104 into ejector conduit 106 in the form of a solid filament, dry powder, or other solid form may also be used as feeder mechanism 102.

[0018] In embodiments, the feeder mechanism 102 may be any suitable mechanism for supplying liquid printing material, such as a liquid filament, into the ejector conduit 106 and advancing the liquid printing material to the ejector nozzle 108. Examples of suitable feeder mechanisms for liquid printing material include mechanisms that advance liquid from a reservoir or other source of printing material (e.g., molten metal), thereby using capillary force and / or overpressure sufficient to steadily refill the ejector nozzle 108 after ejection (e.g., the feeder mechanism may be designed to automatically refill the ejector nozzle after ejection). The feeder mechanism 102 may include, for example, a pump, a feeder conduit, and / or a printing material reservoir configuration that can be filled with printing material to provide a hydrostatic head (e.g., by maintaining a certain fill level of printing material in the reservoir), or any other device for applying pressure. Such feeder mechanisms are well known in the art. Those skilled in the art will be able to readily determine an appropriate feeder mechanism.

[0019] In one embodiment, the feeder mechanism 102 can supply printing material to each ejector conduit 106 at a different feed rate. As an example, a feeder mechanism 102 for advancing multiple filaments includes separate mechanisms for incrementally advancing each of the multiple filaments at separately controllable feed rates. Thus, in one embodiment, as the ejection rate at each ejector increases or decreases as desired for printing, the feed rate can accommodate a replenishment of printing material 104 to the ejector nozzle before the next ejection.

[0020] The multiple ejector conduits 106, including the ejector nozzles 108, can comprise any material capable of withstanding jetting process temperatures, which vary widely depending on the printing material 104 being printed, while maintaining desired structural integrity and energy transfer characteristics, such as light absorption and / or light transmission characteristics. In one embodiment, the material is a refractory material. For purposes of this disclosure, the term "refractory material" is broadly defined as any material having a melting point of 1000°C or greater at 1 atmosphere pressure. For example, the refractory material can have a melting point in the range of 1000°C to about 4000°C, such as about 1200°C to about 4000°C, or about 1400°C to about 3500°C, or about 1700°C to about 3500°C, or about 2000°C to about 3500°C. The ejector conduit material can have a melting point outside of these ranges. For example, if the printing material 104 is a polymer, the ejector conduit could be made of a material having a melting point less than 1000° C., such as 800° C., 700° C., 500° C. or less. The material used for the ejector conduit 106 can be selected from a material such as a refractory material that is transparent to radiation 112, a material such as a refractory material that absorbs radiant energy 112, or a combination thereof.

[0021] 1 , the ejector conduit 106 including the ejector nozzle 108 can include a transparent material 114 that allows radiation 112 (e.g., radiation at wavelengths described herein) to penetrate the sidewalls of the ejector conduit and directly impinge on the printing material 104, according to one embodiment of the present disclosure. The transparent material 114 can include any material that has both desired transparency and fire-resistant properties, which can depend, among other things, on the wavelength of the radiation 112 and the printing material expansion temperature. Examples include materials selected from doped or undoped amorphous silica (e.g., fused silica) and sapphire. In one embodiment, the sidewalls of the ejector conduit 106 can be designed such that the transparent material 114 refracts excess portions of the radiant energy 112 that strike the sides of the ejector conduit 106 but would otherwise escape the printing material 104, such that the excess portions are redirected toward a portion of the passage 106C within the ejector nozzle 108 to impinge on the printing material 104 during operation of the printer-jetting mechanism 100. For example, the cylindrically shaped glass ejector conduit 106 can act as a lens to refract light inward so that it strikes a reflective surface (e.g., ejector housing 120) on the back side of the ejector conduit 106. The reflective surface can then focus the light onto the inner diameter of the ejector conduit 106 so that it can strike the printing material 104.

[0022] In another embodiment, the ejector conduits 106, including the ejector nozzles 108, include a combination of transparent and absorbing materials, such as when at least a portion of each of the multiple ejector conduits 106 includes a material, such as a refractory material, suitable for absorbing radiant energy and converting it to thermal energy in an amount sufficient to cause expansion of the printing material within the ejector nozzles 108. An example of such an embodiment is illustrated in FIG. 2, which shows multiple ejector conduits 106 including a layer of transparent material 114, which may be any of the transparent materials described above, and a layer of optically absorbing material 116 suitable for absorbing radiant energy 112. The layer of optically absorbing material 116 is disposed, for example, to form the inner surface of the multiple ejector conduits 106. Any material having the desired radiation absorbing and refractory properties can be used. For example, the layer of optically absorbing material 116 may include at least one material selected from diamond-like carbon, graphite, black chrome, and black alumina. The layer of optically absorbing material 116 can have any suitable thickness that provides the desired thermal energy to the printing material 104. By way of example, the thickness can be approximately equal to the optical absorption length of the material at the wavelength of the radiant energy 112. Thicker layers can be used, but increasing the thickness can reduce the amount of thermal energy transferred to the filament material. Example thicknesses range from about 10 nm to about 10,000 nm, such as from about 25 nm to about 1,000 nm, or from about 50 nm to about 500 nm, or about 100 nm.

[0023] Other configurations may be used for the ejector conduit 106. In one embodiment, the ejector conduit 106, including the ejector nozzle 108, may include only the absorbent material 116, without the transparent material 114. For example, the entire ejector conduit 106 could comprise a thin-walled metal conduit having high thermal conductance, such as copper, a copper alloy, a refractory metal, or other metal having a suitably high thermal conductance and melting point for printing applications.

[0024] While the entire ejector conduit, including the ejector nozzle 108, can comprise the same material, in alternative embodiments, the ejector nozzle 108 can comprise a different material from the rest of the ejector conduit 106. For example, the ejector nozzle can comprise a transparent material 114 that allows radiation 112 to strike the printing material 104, while the remainder of the ejector conduit 106 can comprise a material such as graphite, platinum, platinum alloys, tungsten, tungsten alloys, other metals with suitably high melting points, such as refractory metals, or non-transparent refractory materials, such as ceramic materials. In yet another example, the ejector nozzle 108 can comprise a transparent material 114 and a layer 116 of optically absorbing material, similar to that described above for the ejector conduit 106 of FIG. 2, while the remainder of the ejector conduit 106 can comprise a single material or a combination of materials different from those used in the ejector nozzle 108. As used herein, the term "refractory metal" is defined to include elemental refractory metals and their alloys, including, for example, niobium, molybdenum, tantalum, tungsten, rhenium, titanium, vanadium, chromium, zirconium, hafnium, ruthenium, rhodium, osmium, iridium, and alloys of any of these metals, such as alloys of two or more of any of the refractory metals listed herein, or alloys of one or more of the refractory metals with other metals, such as iron, nickel, copper, silver, etc. Suitable refractory metal alloys are known in the art.

[0025] FIG. 5A illustrates a configuration of an ejector conduit 106 that may be used in any of the printer ejection mechanisms 100 described herein, according to one embodiment of the present disclosure. The ejector conduit 106 of FIG. 5A includes at least one window 108a disposed proximate to the top of the ejector nozzle 108. The at least one window 108a allows radiant energy 112 from the radiant energy source 110 to be transmitted therethrough and absorbed by a portion of the printing material 104 disposed proximate to the at least one window 108a. FIG. 5A shows a cross-section of a conduit 106 having windows 108a on two opposing sides of the ejector nozzle 108. In one embodiment, the windows 108a may be two separate windows disposed on opposite sides of the ejector nozzle 108 of a size sufficient to allow a desired amount of radiant energy 112. In another embodiment, the ejector nozzle 108 of FIG. 5A may include a single window 108a extending around the entire circumference of the ejector nozzle 108. In another embodiment (not shown), a single window 108a may be located on one side of the ejector nozzle 108 with no window located on the opposite side of the ejector nozzle 108. As described in more detail below, other configurations of the window 108a are possible so long as they allow sufficient transmission of the radiant energy 112 at the desired location of the nozzle 108 to provide the motive force for ejecting the printing material 104b from the ejector nozzle. At least one window 108a comprises a material that is transparent to the radiant energy 112, such as fused silica or sapphire, or any of the transparent materials 114 described herein. The lower portion 108b of the ejector nozzle 108 may comprise an opaque material. Examples of such opaque materials include graphite, platinum, platinum alloys, tungsten, tungsten alloys, other suitable metals such as refractory metals, or any of the refractory materials listed herein that are opaque, such as ceramic materials. In an alternative embodiment, at least one window 108a can extend the entire length of the nozzle 108 if it is desired to heat the printed material throughout the nozzle.In yet another embodiment, if it is desired to heat the printed material only below the nozzle, the at least one window may be located below the nozzle, such as at or near the tip of the nozzle 108, rather than adjacent to the upper portion of the ejector nozzle 108 as shown in FIG. 5A. In such an embodiment, the nozzle 108 may include an opaque material above and / or below the window, such as any of the opaque materials described herein.

[0026] In one embodiment, as described in more detail below, the printing material 104 proximate to at least one window 108a is heated (e.g., from a liquid to a gas) by absorption of radiant energy 112 to provide the desired expansion and ejection of the printing material 104 from the ejector nozzle 108. The length Lw of the window 108 can be any desired length that allows for sufficient delivery of radiant energy 112 to heat and vaporize a desired amount of the printing material 104 to drive the ejection of the printing material from the ejector nozzle 108. w Examples of suitable values ​​of are about 5 micrometers to about 1000 micrometers, such as about 5 micrometers to about 500 micrometers, such as about 10 micrometers to about 100 micrometers, or about 15 micrometers to about 50 micrometers.

[0027] In one embodiment, the exterior surface of any of the ejector nozzles 108 described herein can be coated with an anti-reflective coating to reduce reflection of radiant energy 112 and thereby directly or indirectly increase absorption of the energy in the printing material 104. Examples of suitable anti-reflective coatings, such as stacks of dielectrics or dielectrics that include other materials, are well known in the art.

[0028] Referring to FIG. 2 , multiple ejector conduits 106 are supported within an ejector housing 120. The ejector conduits 106 may be separate structures from the housing material and may be attached to the ejector housing 120 in any suitable manner. In alternative embodiments, the multiple ejector conduits may be integral with the ejector housing 120. For example, the conduits may be formed as capillary tubes or larger conduits that are drilled or otherwise formed directly in the housing material. The conduits may optionally be coated to provide an inner surface of the ejector conduits 106 comprising a material that is different from, but integral with, the ejector housing 120. Techniques for forming such conduits directly in the housing material, as well as techniques for coating the conduits, are generally known. In embodiments, the ejector conduits 106 may comprise a different material than, or the same material as, the ejector housing 120.

[0029] The ejector housing 120 comprises any suitable material capable of withstanding the ejection process temperatures and providing the desired support for the ejector conduit 106. Examples of suitable housing materials include metals such as aluminum, copper, brass, and steel, refractory metals, ceramics, other refractory materials, polymers capable of withstanding the process temperatures (e.g., polymers having melting points of 150°C to 650°C or higher, such as 200°C to 300°C), and combinations thereof, such as metal-coated ceramics and ceramic-coated metals. An example of a composite housing material is copper clad with a ceramic, such as mullite, where the copper and mullite have similar thermal expansion coefficients. The specific material used will depend on the printing material being ejected.

[0030] The ejector housing 120 includes an inlet 122 where a portion of the housing wall is removed to allow radiant energy 112 from the radiant energy source 110 to impinge on the ejector nozzle 108 of each of the plurality of ejector conduits 106. By way of example, such an inlet 122 is shown by a dotted line in Figures 1, 2, and 4. For example, in Figure 1, the area below the dotted line is an opening in the ejector housing that is the inlet 122.

[0031] The radiant energy source 110 can be any suitable radiant energy source that provides the desired thermal energy for expansion of the printing material 104 in a relatively short period of time. In one example, the radiant energy source 110 is a laser. Examples of suitable types of lasers include fiber lasers, modulated lasers, scanned lasers, and scanned, modulated lasers, as well as others. As illustrated in FIGS. 2 and 4 , the radiant energy sources 110 can be positioned on one, two, or more sides of the array and can be positioned to impinge on each ejector nozzle 108 of the multiple ejector conduits during operation of the printer jetting mechanism 100. While the radiant energy sources 110 are shown positioned so that radiant energy 112 from one radiant energy source impinges on each ejector nozzle 108, multiple radiant energy sources can be positioned to impinge on each ejector nozzle 108 through one or more inlets 122 if it is desired to provide an increased heat flux to the printing material 104. The radiant energy source 110 has sufficient power to heat the printing material 104 within the ejector nozzle 108 and expand the printing material 104 rapidly enough to provide sufficient momentum to eject or jet at least a portion of the printing material from the ejector nozzle 108. The rapid expansion of the printing material that results in the desired ejection of the printing material, also referred to herein as jetting, may or may not include heating that causes a phase change in the printing material, as described in more detail below.

[0032] In one embodiment, at least a portion of the ejector housing 120 comprises a reflective surface 124. The reflective surface may surround the inlet 122 to reflect the radiant energy 112 toward the ejector nozzle 108 during printing, which may allow for more efficient and / or more uniform heating and / or expansion of the printing material 104.

[0033] In one embodiment, the ejector housing 120 includes a heating mechanism 126 for heating at least a portion of the ejector housing 120 surrounding the ejector conduit 106 during operation of the three-dimensional printer. The heating mechanism 126 is separate from the multiple radiant energy sources 110. The heating mechanism 126 can provide sufficient thermal energy to bring the printing material 104 to or just below a desired printing material expansion temperature. For example, if the expansion to provide the ejection momentum of the printing material does not involve a phase change, the heating mechanism 126 can provide sufficient thermal energy to bring the printing material 104 to a melting temperature or just above the melting temperature. Alternatively, in the case of a phase-change expansion, the heating mechanism 126 can provide sufficient thermal energy to bring the printing material 104 to or below the melting or vaporization temperature of the printing material 104, as desired, to provide the printing material momentum for ejection. In embodiments where a phase change of the printing material occurs, by controlling the printing material temperature near the ejection site, heat loss away from the ejector nozzle 108 (e.g., melting or vaporizing zones) can be reduced because the phase change is an isothermal process. In embodiments where the printing material 104 is solid before the phase change, a temperature below the melting temperature may be desirable to ensure re-solidification of un-ejected material before the next ejection event.

[0034] The heating mechanism 126 may include, for example, any suitable type of resistive heater, inductive heater, radiant heater, or any combination thereof. For example, the heating mechanism 126 may comprise a heating element embedded in or disposed proximate to the conduit 106 and / or the ejector housing 120, as illustrated in FIGS. 2 and 4 . The heating element may be in the form of, for example, a resistive heating coil or an inductive coil. As an example, a suitable resistive heating mechanism comprises an ohmic serpentine trace embedded in the ejector housing 120 or the ejector conduit 106 surrounding the passage 106C. As used herein, the term “ohmic serpentine trace” refers to a conductive heating element having a nonlinear path along its longitudinal axis (e.g., a wire suitable for resistive heating having a zigzag, wound, or otherwise curved path). The heating mechanism 126 is separate from the multiple radiant energy sources 110.

[0035] In one embodiment, the array of ejector conduits 106 includes M columns of ejector conduits arranged on the X-axis and N rows of ejector conduits arranged on the Y-axis, where M is an integer between 2 and 1000 and N is an integer between 1 and 2. For example, for the array of Figure 2, M is 3 and N is 1, while for the array of Figure 9, M is 3 and N is 2. In other examples, M is an integer between 5 and 1000, between 50 and 1000, or between 100 and 500.

[0036] In one embodiment, the rows of the ejector conduits 106 are arranged linearly, with the ejector conduits 106 in each row being staggered relative to the ejector conduits in adjacent rows to facilitate close packing, for example, as shown in Figure 4. In an alternative embodiment (not shown), the columns of the ejector conduits 106 are arranged linearly, with the ejector conduits 106 in each column being staggered relative to the ejector conduits in adjacent columns.

[0037] In one embodiment, the ejector conduit 106 includes one or more vents 130, as illustrated in FIG. 6 . The vents 130 may be located within or immediately above the ejector nozzle 108. The vents allow air or other ambient gases (as illustrated by arrows 132) to flow from outside the ejector conduit 106 into the ejector conduit 106 and / or into the ejector nozzle 108 as the printing material 104 is ejected. This may allow the printing material to be ejected from the ejector nozzle 108 and more easily separated from the remaining printing material 104 in the ejector conduit 106 and / or more easily ejected from the ejector nozzle 108. The one or more vents 130 may be in any form that allows ambient gases to flow into the nozzle as the printing material 104 is ejected. FIGS. 7A and 7B illustrate another example in which the vents 130 take the form of grooves on the interior surface of the ejector nozzle 108. Any other suitable vent configurations can be used. In one embodiment, the vent 130, such as those in Figures 6, 7A, and 7B, has dimensions that are small enough so that the surface tension of the liquid printing material 104 does not allow a large amount of printing material to flow out of the ejector conduit through the vent 130, but large enough to allow ambient gas to flow through the groove and into the ejector nozzle 108. For example, the width and / or length of the vent 130 in Figure 6, or the diameter in the case of a circular vent (not shown), or the groove width in Figure 7, can be 10 times or more smaller than the inner width (e.g., diameter) of the ejector nozzle so that penetration of the liquid printing material is reduced or eliminated. The vents can be formed by any suitable means, such as by etching techniques or laser ablation, as known in the art.

[0038] This disclosure is not intended to be limited to any particular droplet ejection and / or detachment mode. For example, droplets can neck off and detach in a detachment zone inside the ejector conduit 106, but droplets can also neck off and detach outside the ejector conduit 106, followed by retraction of the undetached printing material 104 into the ejector conduit 106. Thus, modes of droplet ejection can include expansion "extrusion" of the molten printing material 104 from the ejector nozzle 108 into free space, followed by deceleration / retraction of the extruded printing material 104 as the heating pulse ends and the printing material 104 cools / contracts. Other modes of droplet ejection and / or detachment can also be implemented.

[0039] In one embodiment, ejecting at least a portion of the printing material includes flowing a sheath gas proximate the ejector nozzle, where the sheath gas includes one or both of an inert gas and a reducing gas. An example using a sheath gas is illustrated by arrow 210 in FIG. 10 . The sheath gas flow can be accomplished in any suitable manner, such as by flowing the sheath gas through a sheath gas vent 212 disposed within the ejector housing 120. In one embodiment, the sheath gas is maintained at a desired temperature to avoid cooling the printing material prior to deposition. For example, the sheath gas temperature can be at or above the melting point of the printing material. In this manner, the printing material can be maintained in a molten state until deposition onto the substrate occurs, if desired. In one embodiment, the sheath gas can move at approximately the same speed and in approximately the same direction as the droplets when they are ejected.

[0040] The printer-jetting mechanism 100 described herein can be used in any type of printer suitable for jetting printing material. In one embodiment, the printer is a three-dimensional (“3D”) printer that can be used to print 3D objects. A block diagram of an example 3D printer 150 is shown in FIG. 8 . The 3D printer 150 can include any of the printer-jetting mechanisms 100 described herein, including an array 107 of ejector conduits 106. Additionally, the 3D printer can include a positioning system 152 for controlling the relative position of the array 107 with respect to a printed circuit board 154. The phrase “controlling the relative position of the array 107 with respect to the printed circuit board 154” means that one or both of the array 107 and the printed circuit board 154 can move to change the relative positions of the array and the printed circuit board. The relative position of the printed circuit board 154 and the array 107 is modified during printing such that the printed circuit board 154 is positioned to receive jettable printing material 104 from the multiple ejector conduits, thereby forming the 3D object. Positioning system 152 can include one or both of a printed circuit board handling mechanism 156 for positioning printed circuit board 154 and an array positioning mechanism 158 for positioning other parts of printer jetting mechanism 100, such as array 107 and optionally multiple radiant energy sources 110. Printed circuit board 154 can include any substrate on which it is desirable to print a three-dimensional object. An example of a printed circuit board 154 is a build plate that is part of 3D printer 150 or other temporary substrate from which the 3D object can be detached after printing. In another example, printed circuit board 154 can be intended to be permanently attached to the three-dimensional object after printing, such as when printed circuit board 154 is a printed circuit board on which a portion of a circuit has been printed.

[0041] The printed circuit board handling mechanism 156 may be any mechanism suitable for positioning the printed circuit board 154 to receive jettable printing material from multiple ejector conduits disposed within the array 107 during operation of the 3D printer 150. In one embodiment, the printed circuit board handling mechanism 156 is capable of positioning the printed circuit board 154, such as a mechanism plate or other substrate, by moving the printed circuit board 154 along the x-axis, y-axis, and / or z-axis to a desired location targeted by the jetted printing material. The array positioning mechanism 158 may be any mechanism suitable for moving the array 107 along one or more of the x-axis, y-axis, and / or z-axis to a desired location targeted by the jetted printing material 104. The positioning system 152, including either or both the printed circuit board handling mechanism 156 and the array positioning mechanism 158, may include one or more actuators 180 ( FIG. 11 ), which may function as movers for positioning the printed circuit board 154 and the array 107 relative to one another, for example, using a system including tracks 182. Examples of suitable actuators include electric motors, piezoelectric motors, hydraulic actuators, and pneumatic actuators. FIG. 11 illustrates an example of such a positioning system 152 comprising an actuated (e.g., motorized) XY stage 184 for supporting a printed circuit board 154 and a vertical track system 186 along which all or a portion 100 a of the printer jetting mechanism 100 can be moved using one or more actuators 180 to enable vertical positioning. The portion 100 a of the printer jetting mechanism 100 can include any of the components of the printer jetting mechanism 100 described herein mounted on the vertical track system 186 for vertical positioning, including multiple ejector conduits disposed in the array and multiple radiant energy sources 110. The feeder mechanism 102 can be positioned so that it is not directly mounted to the vertical track system 186 (as illustrated in FIG. 11 ), or in other embodiments, can be directly mounted to the vertical track system 186.

[0042] As mentioned, the positioning system 152 can include one or both of a printed circuit board handling mechanism 156 and an array positioning mechanism 158. By way of example, the printed circuit board handling mechanism 156 can be used to move the printed circuit board 154 along both the x-axis and the y-axis, and the array positioning mechanism 158 can be used to move the array 107, and optionally the entire printer jetting mechanism 100, or any portion thereof, along the z-axis, thereby allowing the printed circuit board 154 and the array 107 to be positioned relative to one another in three dimensions during operation of the 3D printer. By way of example, for purposes of this discussion, the x-axis and z-axis are as illustrated for the printing operation in FIG. 10 , the y-axis (not shown) is in the direction into the paper, the x-axis and y-axis are parallel to the top surface of the printed circuit board 154, and the z-axis is perpendicular to the top surface of the printed circuit board 154. In one embodiment, the printed circuit board 154 is a build plate, optionally using a heating mechanism 155 that can heat the build plate to a desired deposition temperature. Suitable build plates, including build plates with heating mechanisms, are well known in the art.

[0043] Method for jetting printing material An embodiment of the present disclosure is directed to a method for ejecting printing material from a printer ejection mechanism. As illustrated in FIG. 9 at 200, the method includes supplying printing material 104 to a plurality of ejector conduits 106 arranged in an array. The ejector conduits 106 have a first end 106A configured to receive the printing material and a second end 106B comprising an ejector nozzle 108. The ejector nozzle 108 can have an internal width (e.g., diameter) ranging from about 10 micrometers to about 1000 micrometers, for example, or any of the internal widths of other ejector nozzles disclosed herein. In the method described herein, the ejector nozzle 108 is irradiated with radiant energy 112 to provide thermally induced expansion and ejection of the printing material, as discussed in more detail below.

[0044] As shown in 202 of FIG. 9 , the printing material 104 is advanced into one or more of the ejector conduits 106 of the array until the printing material 104 is disposed within an ejector nozzle 108 of the one or more ejector conduits 106. In one embodiment, the printing material 104 includes a plurality of filaments. Individual filaments of the plurality of filaments can be advanced into each of the one or more ejector conduits 106 to supply the printing material at a desired feed rate. The desired feed rate can be different for each filament depending on the rate at which the printing material is being ejected from the associated ejector nozzle 108, which in turn depends on the number of jets per unit time from each nozzle and the droplet size per jet.

[0045] The droplet size per jet may be selected based on a variety of factors, including the desired size of the printed object detail, the specific properties of the printing material (e.g., heat transfer and expansion properties), the power of the radiant energy source, the nozzle size, etc. The droplets may generally have a diameter size as small as the inner diameter of the jetting nozzle 108, but may have significantly larger diameters if a longer length of filament is heated during a single jet. A trade-off between power and droplet size may be considered when determining the amount of printing material heated for each jet. In particular, longer lengths of filament can be heated with proportionally higher power, allowing for longer lengths of printing material to be jetted. In one embodiment, the length of heated printing material per pulse is about 1 to about 10 times the inner width of the printing nozzle 108 per jet of printing material (this is approximately the same as the filament width, d, if a solid filament is delivered directly to the print nozzle). p (e.g., can be about the same as the filament diameter). Thus, as an example, the filament can be stepped forward from about 1 filament width per laser pulse to about 10 filament widths per laser pulse, the laser pulse melting each length of the filament as it steps forward.

[0046] The cross-sectional shape of the printing material 104 has a diameter d p3 is a circle having a cross-sectional shape, it should be noted that filaments having any other cross-sectional shape can be used as the printing material 104, such as, for example, a polygon, a rectangle, an ellipse, or other shape. The cross-sectional shape of the solid filament can be the same as that of the cross-sectional shape of the ejector nozzle 108 (e.g., small in size to allow feeding of the filament through the nozzle). Alternatively, the solid filament can have a cross-sectional shape that is different from the cross-sectional shape of the ejector nozzle 108. For purposes of this disclosure, a filament width d of a cross-sectional shape other than a circle is considered to be a p is the widest cross-sectional dimension (e.g., the diagonal between two opposite vertices of a square cross-section), where the cross-section lies in a plane perpendicular in all directions to the longitudinal axis of the filament. "Filament width" is also referred to herein as "diameter," although the term "diameter" can be interchanged with "width" when discussing the diameter of a filament throughout this disclosure.

[0047] As shown in FIG. 9 at 204, the printing material 104 disposed in at least one of the ejector nozzles 108 is heated by radiant energy 112, thereby expanding the printing material 104 to provide sufficient momentum to eject at least a portion of the printing material from at least one of the ejector nozzles. This process can include the printing material 104 undergoing a phase change from a first phase to a second phase to achieve the desired expansion. In one example of phase-change expansion, the filaments are supplied to the ejector nozzle 108 as the printing material 104 in a solid phase. Heating the printing material 104 disposed within the ejector nozzle 108 uses a single pulse of radiation 112 from the radiant energy source 110 to melt individual filaments to provide the desired momentum of the printing material for ejection. In another example of phase-change expansion, the printing material 104 is supplied to the ejector nozzle 108 in a liquid phase. Heating of the printing material 104 disposed within the ejector nozzle 108 uses a single pulse of radiation 112 from a radiant energy source 110 to vaporize at least a portion of the liquid printing material 104 to provide the desired momentum of the printing material for ejection. In yet another embodiment, the printing material 104 is supplied to the ejector nozzle 108 as a liquid and expands without changing phase to eject the liquid from the ejector nozzle 108. The printing material 104 is expanded sufficiently rapidly using a single radiation pulse to provide the desired momentum of the printing material for ejection.

[0048] The pulse length of the radiant energy 112 can be any duration that provides the desired expansion and ejection of the printing material 104. Examples of suitable pulse lengths range from about 0.1 microseconds to about 100 milliseconds, or from about 1 microsecond to about 1000 microseconds, or from about 1 microsecond to about 100 microseconds. The rapid heating for the phase change causes the printing material 104 to expand axially within the ejector nozzle 108, thereby providing sufficient momentum to the printing material 104 to eject at least a portion of the printing material from the ejector nozzle 108. In addition to enabling sufficient momentum for ejection, the rapid heating can also potentially enable a rapid ejection rate (e.g., multiple ejections of printing material per second from the same ejector nozzle). While achieving expansion of the printing material 104 using a single radiation pulse, it can also be useful to use two or more radiation pulses to achieve the expansion, either from the same or multiple radiant energy sources, as long as the expansion of the printing material occurs rapidly enough to achieve the desired momentum of the printing material for ejection from the ejector nozzle. For example, two, three, or more rapid pulses can be used to achieve the desired expansion of the printed material as opposed to a single longer pulse.

[0049] After ejection of the printing material 104, additional printing material can be advanced into the ejector nozzle or nozzles 108, and then the heating to a phase change process can be repeated to eject additional printing material. This process of advancing printing material and heating the printing material can be repeated any number of times desired for each of the ejector nozzles 108 in the array until printing is complete. During printing, heating and ejection of the printing material 104 can occur from a single ejector nozzle 108 in the array, simultaneously from two or more ejector nozzles 108, and / or simultaneously from all of the ejector nozzles 108 in the array, as desired to accomplish the particular printing process being performed.

[0050] Any printing material that expands sufficiently during the phase change to generate sufficient momentum for ejection can be used. In one example, the printing material includes at least one substance selected from metals, polymers, and metal oxides (e.g., doped or undoped silica, such as glass), such as tin, tin alloys, lead, lead alloys (e.g., solders containing one or both of tin and lead), aluminum, aluminum alloys (e.g., 1000 series, 2000 series, 3000 series, 4000 series, 5000 series, 6000 series such as 6061 and 6063, and 7000 series aluminum alloys), iron, iron alloys (e.g., steel), nickel, nickel alloys (e.g., zinc), nickel, nickel alloys, titanium, titanium alloys, tungsten, tungsten alloys, silver, and silver alloys. Suitable alloys of the above elemental metal printing materials (e.g., nickel, titanium, tungsten, silver, etc.) are well known in the art. In one embodiment, the printing material 104 has a metal content of greater than 90% by weight, e.g., between about 95% and 100%, or between 98% and 100%, or between 99% and 100%, or between 99.5% and 100%, or between 9.8% and 100%, or between 99.9% and 100% by weight. In one embodiment, the printing material 104 has a metal content of about 1x10 at 20°C (e.g., is conductive at room temperature (20°C)). -7 Ohms * m ~ approx. x 1x10 -8 Ohms * m, etc., 1x10 at 20°C -6 Ohms * It has a resistivity less than m.

[0051] Any of the printing materials described herein can be in the form of multiple solid or liquid filaments. In the case of solid filaments, the width of an individual filament, d p is the inner width of the ejector nozzle 108, d iThe width (e.g., diameter), d, is optionally selected to be slightly smaller than or substantially the same as the width (e.g., diameter), d, of the individual filaments, and is arranged to provide a close fit around the individual filaments, thereby allowing the filaments to still be positioned within the ejector nozzle 108. The fit is close enough so that when the portion of the filament within the ejector nozzle undergoes expansion, the printed material expands axially at a sufficient velocity to eject at least a portion of the filament material from the ejector nozzle 108. As an example, the filament width (e.g., diameter), d p is about 0.1% to about 3% smaller, or about 0.5% to about 1.5% smaller than the ejector nozzle width (e.g., diameter), d i 0 to about 4% smaller than d p and d i The relative sizes of the may depend on various factors, such as the expansion characteristics of the printing material during phase change, the desired momentum of the printing material when ejected, the heating rate of the printing material within the ejector nozzle, and others. As an additional example, the filament width (e.g., diameter), which may be either a liquid filament or a solid filament, may be about 0.01 micrometers to 20 micrometers smaller than the nozzle internal width (e.g., diameter), such as about 0.1 micrometers to about 10 micrometers, or about 1 micrometer to about 5 micrometers, or about 0.1 micrometers to about 2 micrometers, or about 0.1 micrometers to about 1 micrometer smaller than the nozzle internal width (e.g., diameter).

[0052] The printing material can have a width (e.g., diameter) ranging from about 10 micrometers to about 1000 micrometers, from about 20 micrometers to about 500 micrometers, from about 50 micrometers to about 200 micrometers, or about 100 micrometers. Printing materials (e.g., solid or liquid filaments) with relatively small widths (e.g., diameters) can have the advantage of faster heating throughout their thickness because thermal diffusivity determines the heat propagation time from the periphery to the center of the filament. The ability to heat and expand the entire thickness of the filament in short bursts can allow for increased control over jet momentum and / or jet volume (e.g., droplet size), among other things. A small diameter can also allow for smaller, discrete, jettable amounts of printing material (e.g., smaller droplet sizes ejected from the ejection nozzle 108). Therefore, for these reasons, filaments with relatively small diameters may be preferred. The desired small diameter size will depend on the thermal diffusivity characteristics of the printing material, as well as other factors. In one embodiment, the width of the printed material (e.g., the diameter of a solid or liquid filament) ranges from about 10 micrometers to about 100 micrometers, such as from about 10 micrometers to about 50 micrometers, or from about 10 micrometers to about 25 micrometers. The inner width (e.g., diameter) of the ejector nozzle can be sized as described above to provide a close fit around individual filaments while still allowing the filaments to be positioned within the ejector nozzle.

[0053] During heating using radiant energy, any radiation from the radiant energy source 110 that would not otherwise strike the printing material 104 may be directed toward the printing material 104 by refraction in the transparent material 114 of the ejector conduit 106 and / or reflection from the reflective surface 124 of the ejector housing 120, as described above. In one embodiment, a laser beam wider than the filament diameter may be used. The excess portion of the laser beam that does not directly strike the printing material 104 may be refracted and / or reflected off the printing material to more uniformly heat the entire surface of the printing material.

[0054] In embodiments in which the radiant energy 112 is absorbed directly by the printing material 104 (e.g., as opposed to being absorbed by a layer of heat-absorbing material 116), the printing material 104 may be provided with a modified surface (either by an in-line process or during manufacturing) that increases absorption at the radiant energy wavelength (e.g., laser wavelength) compared to the same printing material without the modified surface. This may include modifying the color of the filament surface to reduce reflection, applying an anti-reflective coating to the solid filament, and / or treating the filament surface in some other manner. As an example, anodic etching of the surface of the solid printing material 104 is one treatment method that may be used to increase radiation absorption. Anodic etching may be particularly useful for increasing the absorption of highly reflective solid metal filaments. Note that an anodized surface may lose its absorption capacity before the radiant energy is fully absorbed. Using such a filament as the printing material in the methods of the present disclosure may help increase the rate of expansion of the printing material, which in turn may increase the deposition rate of the jetted printing material. In one example, the modified surface can absorb approximately 90% to 100% of the incident illumination at the wavelength of the radiant energy.

[0055] In embodiments, printing material 104 is supplied to the ejector conduit as either a liquid or a solid and ejected from the ejector nozzle 108 as a liquid in the form of droplets. The droplets may optionally have a relatively small droplet size, which may enable printing of fine detail. By way of example, droplet diameters may range from about 0.001 mm to about 0.2 mm, from about 0.005 mm to about 0.1 mm, and from about 0.01 mm to about 0.05 mm. Larger diameter droplets may also be formed if desired.

[0056] In another embodiment, the printing material 104 is supplied to the ejector nozzle 108 as a liquid first phase, and then a portion of the printing material is heated to a vapor second phase. Referring to FIGS. 5A and 5B , in such a process, at least a portion of the passage 106C in front of the ejector nozzle 108 is filled with molten printing material (e.g., any of the printing materials described herein). As described herein, all or a portion of the passage 106C can optionally be tapered. Using radiant energy 112 from a radiant energy source 110 transmitted through at least one window 108a, a first portion 104a of the molten printing material 104 adjacent to the window 108a is vaporized by rapid heating within the ejector nozzle 108, while a second portion 104b between the first portion 104a and the tip of the ejector nozzle 108 remains liquid. The vaporized portion 104a of the printing material 104 expands axially to provide sufficient motive force to eject a liquid second portion 104b of the printing material from the ejector nozzle 108. In one embodiment, the printing material 104 may be initially fed as a solid to the first end 106A of the ejector conduit 106 using the feeder mechanism 102, melted before being introduced to the ejector nozzle 108, such as by using heat from the heating mechanism 126, and then vaporized by rapid heating within the ejector nozzle 108 to provide the desired motive force for jetting. Alternatively, the printing material 104 may be fed as a liquid to the first end 106A of the ejector conduit 106 using the feeder mechanism 102, maintained as a liquid using heat from the heating mechanism 126, and then vaporized by rapid heating caused by radiant energy 112 impinging on the ejector nozzle 108 to provide the desired motive force for jetting.

[0057] In embodiments where the printing material 104 is a solid and then changes phase to a liquid, controlling the printing material temperature to be below the melting temperature after each ejection may be desirable to ensure re-solidification of un-ejected material before the next ejection event.

[0058] The disclosed methods may be used to deposit printing material 104 simultaneously or separately from any number of ejector conduits 106, as desired, and may allow for the deposition of small amounts of material from any one ejector nozzle 108 while providing a relatively high overall deposition rate due to the potentially large number of ejector conduits 106 in the array and the potential ejection velocity from each ejector conduit 106.

[0059] The printer jetting mechanisms for jet printing materials described herein can be used in various printing methods. For example, any of the printer jetting mechanisms described herein can be used in a method of three-dimensional printing in which printing material 104 is ejected from ejector nozzles 108 and deposited onto a printed circuit board 154, such as a build plate. One or both of the printed circuit board 154 and the array 107 of ejector nozzles 108 can move relative to one another in three dimensions (e.g., along the x-, y-, and z-axes) during printing in any manner as described herein, thereby forming a 3D object. As is well known in the art, 3D printing involves printing multiple droplets or layers of material, each of which can be stacked on top of each other until a desired thickness of the 3D object is achieved. FIG. 10 illustrates an example of a printer jetting mechanism 100 including multiple ejector conduits 106 that simultaneously eject droplets 200 to print a 3D object 202 on the printed circuit board 154. Many layers 204 of droplets 200 can be deposited, one layer or droplet after the other, until the 3D object is complete. As will be readily understood by one skilled in the art, the droplets and / or layers can be stacked in any desired order, for example, a first sub-layer 204 may or may not be completed before beginning a subsequent layer, and there may or may not be a discernible layer pattern relative to the order of material deposition. Rather, the droplets, layers, and / or portions of layers can be stacked in any desired order to complete the 3D object.

[0060] The following examples are illustrative only and are not intended to limit or otherwise affect the scope of the invention as set forth in the claims.

[0061] Theoretical Example Example 1: Solid-to-Liquid Phase Change Expansion: Aluminum, copper, and iron wires each with a diameter of 0.0001 meters are held just below their melting temperature and each is fed into a separate refractory tube (e.g., a fused silica tube) with an inner diameter larger than the outer diameter of the wire. A laser pulse is absorbed by the 0.0001 meter end portion of each wire, melting the wire portion in microseconds. During melting, expansion of the molten wire material occurs primarily along the longitudinal axis of the silica tube. The free meniscus of the molten material accelerates axially within the tube, with the molten region accelerating at approximately half the speed of the meniscus. As shown in Table 1 below, the acceleration of the molten material within the tube corresponds to an energy sufficiently greater than the energy required to detach a droplet of molten material from the wire and eject it from the tube, thus ejecting the droplet from the tube. The energy used to melt a sufficient portion of the wire for ejection is provided by a laser, such as a fiber laser or a scan-modulated laser, that can be pulsed at the desired pulse power.

[0062] The calculations in Table 1 below assume there is no volume between the wire and the tube. Calculated motive force = average acceleration of the melt multiplied by the mass of the melt. "Pulse energy" in the table refers to the energy to melt the length of wire and can potentially be delivered by a single laser pulse.

[0063] [Table 1]

[0064] Example 2: Liquid-to-Liquid Expansion: Each of aluminum, copper, iron, and indium wires, each with a diameter of 0.0001 meters, is fed into a separate refractory tube (e.g., fused silica) with an inner diameter larger than the outer diameter of the wire. A liquid metal, such as mercury (Hg), gallium-indium, or a gallium-indium-tin eutectic mixture, is fed into a similar silica tube. In the case of wire materials, a meniscus of the liquid is placed at the end of a graphite tube to melt at least a portion of each wire and maintain it as a liquid adjacent to the end of the silica tube. A laser pulse is then absorbed by the 0.0001 meter end portion of each silica tube, heating the liquid material therein and raising the temperature by approximately 300 Kelvin in approximately 5 microseconds. During heating, expansion of the liquid material occurs primarily along the longitudinal axis of the silica tube. The free meniscus of the molten material accelerates axially within the tube, and the molten region accelerates at approximately half the speed of the meniscus. As shown below in Table 2, the acceleration of the molten material within the tube corresponds to an energy that exceeds the energy required to detach a droplet of molten material from the liquid and eject it from the tube, thus ejecting the droplet of molten material from the tube. The energy used to heat a sufficient portion of the material for ejection is provided by a laser that can be pulsed at a desired pulse power.

[0065] For the calculations in Table 2 below, Motive Force = Average Acceleration of the Liquid Multiplied by the Mass of the Liquid. "Pulse Energy" in Table 2 refers to the energy required to raise the temperature of the liquid by 300 Kelvin and can potentially be delivered by a single laser pulse.

[0066] [Table 2]

[0067] Example 3: Liquid-to-Vapor Phase Change Expansion: Aluminum, copper, and iron wires each having a diameter of 0.0001 meters are fed into separate refractory tubes (e.g., graphite tubes) with an inner diameter larger than the outer diameter of the wires. A meniscus of the liquid is placed at the end of the graphite tube to melt at least a portion of each wire and maintain it as a liquid adjacent to the end of the graphite tube. The graphite tube includes a window located just above the 100 micrometer graphite end portion of the tube. The window includes a material that is transparent to light emitted from a laser used to vaporize the liquid. The window has a dimension of approximately 25 micrometers along the length of the tube. A laser pulse from the laser is transmitted through the window, vaporizing the liquid material adjacent to the window in approximately 5 microseconds. The end portion of the molten material between the window and the graphite tip remains liquid. During heating, expansion of the vaporized material occurs primarily along the longitudinal axis of the graphite tube, accelerating the end portion of the liquid or molten material axially so that it is ejected from the tube, resulting in droplets of molten material being ejected from the tube. The energy used to heat and vaporize a sufficient portion of the molten material for ejection is supplied by a laser that can be pulsed at a desired pulse power.

[0068] For Table 3 below, "Pulse Energy" refers to the energy used to vaporize a portion of the liquid as described above, and could be supplied by a single laser pulse.

[0069] [Table 3]

[0070] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the present disclosure are approximations, the numerical values ​​set forth in the specific examples are reported as precisely as possible. However, any numerical value inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Furthermore, all ranges disclosed herein should be understood to encompass any and all subranges subsumed therein.

[0071] While the present teachings have been illustrated with respect to one or more implementations, changes and / or modifications can be made to the illustrated embodiments without departing from the spirit and scope of the appended claims. Additionally, while particular features of the present teachings may be disclosed with respect to only one of several implementations, such features may be combined with one or more other features of other implementations as may be desirable and advantageous for any given function or functions. Furthermore, to the extent that the terms "including," "includes," "having," "has," "with," or variations thereof are used in either the detailed description or the claims, such terms are intended to be inclusive in a manner similar to the term "comprising." Furthermore, the term "about" in the discussion and claims herein indicates that the recited values ​​may be varied somewhat unless such variations result in incompatibility of the process or structure to the illustrated implementation. Finally, the term "exemplary" indicates that the description is used as an example, rather than as an ideal.

[0072] It will be appreciated that variations of the above-disclosed and other features and functions, or alternatives thereof, may be combined into many other different systems or applications. Various presently unforeseen or unprecedented alternatives, modifications, variations, or improvements may subsequently occur to those skilled in the art, which are intended to be encompassed by the following claims.

Claims

1. a plurality of ejector conduits arranged in an array, each ejector conduit comprising: a first end positioned to receive printing material; a second end comprising an ejector nozzle; and a passage defined by an inner surface of the ejector conduit for allowing the printing material to pass through the ejector conduit from the first end to the second end; a plurality of radiant energy sources, the plurality of radiant energy sources being positionable such that a path of radiant energy emitted from one or more of the plurality of radiant energy sources during operation of the three-dimensional printer can impinge on the ejector nozzle of each of the plurality of ejector conduits; an ejector housing configured to support the plurality of ejector conduits, the ejector housing including an inlet for allowing the radiant energy to impinge on the ejector nozzle of each of the plurality of ejector conduits, at least a portion of the ejector housing having a reflective surface surrounding the inlet, the reflective surface reflecting the radiant energy toward the ejector nozzle; a positioning system for controlling a relative position of the array with the printed circuit board during operation of the three-dimensional printer in a manner that enables the printed circuit board to receive jettable printing material from the plurality of ejector conduits; and A three-dimensional ("3D") printer comprising:

2. A three-dimensional printer as described in claim 1, further comprising a feeder mechanism for advancing the printing material, the feeder mechanism being a mechanism for advancing multiple filaments.

3. 3. The three dimensional printer of claim 2, wherein the feeder mechanism for advancing the plurality of filaments comprises a separate mechanism for incrementally advancing each of the plurality of filaments at a desired feed rate, the feed rate being individually controllable for each filament.

4. The three-dimensional printer of claim 1 , wherein the plurality of ejector conduits comprises a material that is transparent to the radiant energy.

5. 5. The three dimensional printer of claim 4, wherein the material that is transparent to the radiant energy comprises at least one refractory material selected from fused silica, doped amorphous silica, and sapphire.

6. 5. The three dimensional printer of claim 4, wherein the plurality of ejector conduits further comprise a layer of material suitable for absorbing radiant energy, the layer of material being disposed on the interior surface of the plurality of ejector conduits.

7. 7. The three dimensional printer of claim 6, wherein the layer of material comprises at least one optically absorbing material selected from diamond-like carbon, graphite, black chrome, and black alumina.

8. 5. The three dimensional printer of claim 4, wherein the material that is transparent to the radiant energy is shaped to refract radiant energy during operation of the three dimensional printer in a manner that allows refracted radiant energy to be redirected toward a portion of the passageway within the ejector nozzle.

9. The three-dimensional printer of claim 4 , wherein the material that is transparent to the radiant energy is at least one window disposed within the ejector nozzle.

10. The three dimensional printer of claim 1 , wherein at least a portion of each of the plurality of ejector conduits comprises a material suitable for absorbing the radiant energy.

11. The three dimensional printer of claim 1 , wherein the ejector housing comprises at least one housing material selected from metal, ceramic, and combinations thereof.

12. 10. The three dimensional printer of claim 1, further comprising a heating mechanism for heating at least a portion of the ejector housing surrounding the ejector conduit during operation of the printer, the heating mechanism being separate from the plurality of radiant energy sources.

13. The three-dimensional printer of claim 1 , wherein the ejector nozzle has an inner width in the range of 10 micrometers to 1000 micrometers.

14. The three-dimensional printer of claim 1 , wherein the ejector nozzle is coated with an anti-reflective coating.

15. 2. The three dimensional printer of claim 1, wherein the array has M columns of ejector conduits arranged on an X axis and N rows of ejector conduits arranged on a Y axis, where M is an integer between 2 and 1000, and N is an integer between 1 and 2.

16. 16. The three-dimensional printer according to claim 15, wherein M is an integer in the range of 5 to 1000.

17. 17. The three dimensional printer of claim 16, wherein N is 2, and wherein the rows of the ejector conduits are arranged linearly, with the ejector conduits in each row being staggered relative to the ejector conduits in adjacent rows.

18. a plurality of ejector conduits arranged in an array, each ejector conduit comprising: a first end positioned to receive printing material; a second end comprising an ejector nozzle; and a passage defined by an inner surface of the ejector conduit for allowing the printing material to pass through the ejector conduit from the first end to the second end; a plurality of radiant energy sources, the plurality of radiant energy sources being positionable such that a path of radiant energy emitted from one or more of the plurality of radiant energy sources can impinge on the ejector nozzle of each of the plurality of ejector conduits during operation of the printer ejection mechanism; an ejector housing configured to support the plurality of ejector conduits, the ejector housing including an inlet and a reflective surface at least partially surrounding the inlet, the reflective surface reflecting the radiant energy toward the ejector nozzle; A printer jetting mechanism is provided.

19. 20. The printer ejection mechanism of claim 18, wherein the ejector nozzle has an internal width in the range of 10 micrometers to 1000 micrometers.

20. 20. The printer ejection mechanism of claim 18, wherein the plurality of ejector conduits comprise a material that is transparent to the radiant energy.

21. 21. The printer ejection mechanism of claim 20, wherein the plurality of ejector conduits further comprises a layer of material suitable for absorbing radiant energy, the layer of material being disposed on the interior surface of the plurality of ejector conduits.

22. a plurality of ejector conduits arranged in an array, each ejector conduit comprising: a first end positioned to receive printing material; a second end comprising an ejector nozzle; and a passageway defined by an inner surface of the ejector conduit for allowing the printing material to pass through the ejector conduit from the first end to the second end, the ejector nozzle configured to transmit energy from a radiant energy source to a portion of the passageway within the ejector nozzle, the energy reflecting from three reflective surfaces toward the ejector nozzle; an ejector housing configured to support the plurality of ejector conduits, the ejector housing including an inlet and a reflective surface at least partially surrounding the inlet, the reflective surface reflecting the radiant energy toward the ejector nozzle; A three-dimensional ("3D") printer jetting mechanism comprising:

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