Thermosettable build plate structures for stabilizing metal build surfaces and release

Abstract

Some embodiments of the present disclosure relate to additive manufactured build plate structures for stabilizing metallic build surfaces and easily releasing 3D printed objects during 3D printing. The build plate includes a body having a recess formed through a first surface of the body, the recess including a bottom surface within the body and a sidewall extending to the bottom surface. The recess is configured to be filled with a metal or metal alloy in solid form that provides a printing surface for forming a 3D object in a 3D printing device. The recess includes a locking mechanism configured to prevent uplift of the metal or metal alloy in solid form during 3D printing in the 3D printing apparatus.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 323,194, filed on March 24, 2022, entitled "THERMALLY DECOMPOSABLE BUILD PLATE STRUCTURE FOR STABILIZATION OF METALBUILD SURFACE DURING 3D PRINTING AND FACILE RELEASE OF 3D PRINTED OBJECTS," the entire contents of which are incorporated herein by reference. Background Art

[0003] 3D printing (also known as additive manufacturing) has been growing in popularity as a technology for creating prototypes and industrial parts. These parts have increasingly penetrated all industry categories of industrial manufacturing, including aerospace, automotive and dental industries.

[0004] The process of additive manufacturing involves depositing printing material onto a build plate in sequential layers until the desired 3D print is formed. 3D printing methods build parts layer by layer, but most require a platform or build plate as a starting point. The first few layers of printing material will bond to the surface of the build plate, and subsequent layers will build on this surface. When 3D printing 3D metal printed parts, the feedstock is made of metal powder or a combination of powders. The build plate is placed in the 3D printing machine. Once the machine is turned on, a blade deposits layers of metal powder on top of the build plate. A laser or series of lasers selectively sinter the metal to make it part of the 3D printed object. The first few lasers essentially weld the material that will become the 3D printed object to the build plate. The blade then deposits new powdered metal on the surface of the build plate. Selective sintering is repeated and the object is created layer by layer.

[0005] Despite the increasing application of additive manufacturing in high-tech industries, the separation of parts from the build plate is still commonly accomplished by cutting. Cutting equipment used to separate parts from the build plate includes hacksaws, bandsaws, wire electric discharge machines (EDM), etc. While the use of these devices is effective, it can be time consuming and may require the purchase of a large amount of capital equipment, such as in the case of online EDM. Typically, removal and post-processing equipment accounts for a larger percentage of the workshop area than the machines used for powder bed fusion to manufacture 3D printed parts. In addition, the mechanical separation of 3D printed parts from the build plate may require a large amount of post-processing of the removed parts and the build plate surface. Summary of the invention

[0006] Some embodiments of the present disclosure relate to build plate structures for stabilizing metal build surfaces during 3D printing and easily releasing 3D printed objects.

[0007] In one embodiment, an additive manufacturing build plate includes a body having a recessed portion formed through a first surface of the body, the recessed portion including a bottom surface within the body and a side wall extending to the bottom surface, wherein: the recessed portion is configured to be filled with a metal or metal alloy in solid form, which provides a printing surface for forming a 3D object in a 3D printing device; and the recessed portion includes a locking mechanism, which is configured to prevent the metal or metal alloy in solid form from lifting during 3D printing in the 3D printing device.

[0008] In some embodiments, the locking mechanism includes side walls; and at least one of the side walls is angled such that a circumference of a bottom surface of the recess is greater than a circumference of a top surface of the recess.

[0009] In some embodiments, at least one side wall is inclined at 5 to 45 degrees relative to a perpendicular line to the bottom surface of the recess.

[0010] In some embodiments, the locking mechanism includes a through hole formed through the bottom surface of the recess to a second surface of the body opposite the first surface, the through hole having an opening that is larger at the second surface of the body than at the bottom surface of the recess.

[0011] In some embodiments, the through hole tapers from the second surface of the body to the bottom surface of the recessed portion.

[0012] In some embodiments, the through hole tapers at an angle of 5 to 45 degrees relative to a perpendicular line to the bottom surface of the recessed portion.

[0013] In some embodiments, the through-hole is countersunk or counterbored.

[0014] In some embodiments, the vias are pouring vias for filling the recess with a metal or metal alloy in liquid form, which solidifies into a solid form.

[0015] In some embodiments, the through-holes are air holes configured to release air that is displaced by pouring the metal or metal alloy in liquid form in the recess.

[0016] In some embodiments, the locking mechanism includes one or more blind holes formed through the bottom surface of the recess to the interior of the build plate, each of the one or more blind holes having a smallest opening at the bottom surface of the recess.

[0017] In some embodiments, the locking mechanism includes a channel extending along at least a portion of a sidewall or bottom surface of the recess.

[0018] In some embodiments, the channel comprises a plurality of dovetails.

[0019] In some embodiments, the locking mechanism includes one or more subtractive features that extend partially or completely through the body toward an outer surface of the body.

[0020] In some embodiments, the locking mechanism further comprises one or more additive features in the recess, the one or more additive features comprising one or more positive topographic features.

[0021] In some embodiments, the additive manufacturing build plate further comprises: a metal or metal alloy in solid form within the recess.

[0022] In some embodiments, the solidus temperature of the metal or metal alloy is lower than the solidus temperature of the bulk, and lower than the solidus temperature of the 3D object.

[0023] In one embodiment, a method includes: obtaining an additive manufacturing build plate, which includes a body having a recessed portion formed through a first surface of the body, the recessed portion including a bottom surface within the body and a sidewall extending to the bottom surface; and forming a solid form of metal or metal alloy within the recessed portion, which has a printing surface for forming a 3D object in a 3D printing device, wherein the recessed portion includes a locking mechanism, which is configured to prevent the solid form of the metal or metal alloy from lifting during 3D printing in the 3D printing device.

[0024] In some embodiments, forming a metal or metal alloy in solid form includes pouring the metal or metal alloy in liquid form into a pouring through-hole of a recessed portion, wherein the metal or metal alloy in liquid form solidifies into a solid form; and releasing air expelled by the metal or metal alloy in liquid form through an air through-hole of the recessed portion, wherein: the metal or metal alloy in solid form extends into the pouring through-hole and the air through-hole, the locking mechanism includes the pouring through-hole and the air through-hole, and before being filled with the metal or metal alloy in solid form, the pouring through-hole and the air through-hole each have an opening, and the opening is larger at the outer surface of the body than at the bottom surface of the recessed portion.

[0025] In some embodiments, the method further includes: after forming the solid form of the metal or metal alloy, placing the additive manufacturing build plate in a 3D printing device; and 3D printing a 3D object on the printing surface, wherein the solidus temperature of the metal or metal alloy is lower than the solidus temperature of the additive manufacturing build plate and the 3D object, and the locking mechanism prevents lifting of the solid form of the metal or metal alloy caused at least in part by an increase in the temperature of the metal or metal alloy during 3D printing.

[0026] In one embodiment, a method includes: placing an additive manufacturing build plate in a 3D printing device, the additive manufacturing build plate including: a body having a recessed portion formed through a first surface of the body, the recessed portion including a bottom surface within the body and a side wall extending to the bottom surface; and a solid form of metal or metal alloy within the recessed portion, wherein the solid form includes a printing surface for forming a 3D object in the 3D printing device, the solidus temperature of the metal or metal alloy is lower than the solidus temperature of the additive manufacturing build plate and the 3D object, and the recessed portion includes a locking mechanism; and 3D printing the 3D object on the printing surface of the solid form of the metal or metal alloy, wherein during 3D printing, the locking mechanism prevents the solid form of the metal or metal alloy from lifting due at least in part to an increase in the temperature of the metal or metal alloy.

[0027] In some embodiments, the method further includes: after printing the 3D object, melting the metal or metal alloy in solid form to release the 3D object from the additive manufacturing build plate.

[0028] Other features and aspects of the disclosed technology will become apparent from the following detailed description taken in conjunction with the accompanying drawings, which illustrate, by way of example, features according to embodiments of the disclosed technology. This summary is not intended to limit the scope of any invention described herein, which is defined by the claims and equivalents.

[0029] It should be understood that all combinations of the aforementioned concepts (as long as these concepts are not mutually contradictory) are considered to be part of the inventive subject matter disclosed herein. In particular, all combinations of the claimed subject matter attached to this disclosure are considered to be part of the inventive subject matter disclosed herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] According to one or more embodiments, the present disclosure will be described in detail with reference to the following figures. The figures provided are for illustrative purposes only and only depict example embodiments. In addition, it should be noted that for clarity and ease of description, the elements in the figures are not necessarily drawn to scale.

[0031] Some figures included herein show various embodiments of the disclosed technology from different viewing angles. Although the accompanying descriptive text may refer to such views as "top", "bottom" or "side", such references are merely descriptive and do not imply or require that the disclosed technology be implemented or used in a specific spatial orientation unless otherwise explicitly stated.

[0032] Figure 1AA top view of a build plate according to some embodiments of the present disclosure is shown, the build plate including a locking mechanism for preventing a solid metal printed structure formed in the build plate prior to 3D printing from lifting during 3D printing.

[0033] Figure 1B Shown Figure 1A Bottom view of the build plate.

[0034] Figure 1C Shown Figure 1A Cross-sectional side view of the build plate.

[0035] Figure 1D Demonstrated formation of a solid metal printed structure in the build plate Figure 1A Cross-sectional side view of the build plate.

[0036] Figure 1E A 3D metal printing process according to some embodiments of the present disclosure is shown, which includes using a metal powder bed and a laser to Figure 1D 3D metal printing equipment that forms 3D printed objects on a build plate.

[0037] Figure 1F An assembly according to some embodiments of the present disclosure is shown that includes a metal 3D printed object metallurgically bonded to a build plate after 3D printing is completed.

[0038] Figure 2A A cross-sectional view of another build plate including a locking mechanism for preventing a solid metal printed structure formed in the build plate prior to 3D printing from lifting during 3D printing is shown according to some embodiments of the present disclosure.

[0039] Figure 2B Demonstrated formation of a solid metal printed structure in the build plate Figure 2A Cross-sectional side view of the build plate.

[0040] Figure 3 A top perspective view of another build plate including a locking mechanism for preventing a solid metal printed structure formed in the build plate prior to 3D printing from lifting during 3D printing is shown according to some embodiments of the present disclosure.

[0041] Figure 4A A cross-sectional view showing one example of a combination of positive relief features and subtractive relief features that may be formed on a bottom surface or side surface of a recessed portion of a build plate according to some embodiments of the present disclosure.

[0042] Figure 4BShows the depression filled with solid metal or metal alloy Figure 4A relief features.

[0043] The drawings are not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. DETAILED DESCRIPTION

[0044] In additive manufacturing, there is a need for improved techniques for removing workpieces attached to a build plate. One challenge is to release the part without damaging it while also protecting the build plate so that it can be reused. As mentioned above, mechanical methods are often used, such as using a band saw or wire EDM to cut and remove the 3D printed object from the build plate outside the 3D printer. The build plate can then be machined separately to remove excess material and restore it to a usable state. However, as mentioned above, this method can be time consuming and require a lot of post-processing time. In addition, this method may require additional consumable metal powder to allow for sufficient standoff between the part and the build plate to allow access to the band saw or wire EDM gap.

[0045] One recently proposed technique that has proven effective in removing 3D printed parts and overcoming the above challenges involves a thermally decomposable build plate design that utilizes a metal with a relatively low melting point as a build surface, allowing parts printed via powder bed fusion to be released within seconds using a mild heat treatment. Compared to mechanical removal of 3D printed metal parts, which typically requires hours of post-processing to reshape and polish the base of the object and re-lay the build plate for reuse, the thermally decomposable build plate enables easy removal of the 3D printed object from the build plate without damaging the 3D printed part, and requires little or no post-processing, finishing, reshaping, and / or polishing of the 3D printed object.

[0046] Embodiments of the present disclosure describe additional improvements in the design of thermally decomposable build plates that can help prevent metal printing surfaces from lifting, improve tolerances of printed parts, improve user experience, and increase throughput. To this end, the build plate may include structural features incorporated into the interior of the recessed portion of the build plate and designed to help fix the metal in the internal recessed portion of the build plate to prevent lifting and build failure during 3D printing. As further described below, this structural feature for fixing the metal can be linear, conical, dovetailed, or irregular. There can be one feature or multiple features. There can be a combination of multiple features of the same type or different types of features. These and other embodiments will be further described below.

[0047] Figure 1A , 1B1C and 1C respectively show a top view, a bottom view and a cross-sectional side view of a build plate 100 that can be used for additive manufacturing or 3D printing according to an embodiment of the present disclosure. As shown, the build plate 100 includes a top surface 110, a bottom surface 120 and four side walls extending between the top surface and the bottom surface. The build plate 100 includes a top surface, a bottom surface and a side surface, which can be made of copper, stainless steel, tool steel, tin, aluminum, cemented carbide, ceramic, graphite or some other suitable material. In particular, as further described below, the build plate 100 can be made of a material (e.g., a metal or a metal alloy) that has a solidus temperature much higher than (e.g., at least 30°C) the solidus temperature of the thermally decomposable material placed or formed in its recess 140, and is used to form a bond between the build plate 100 and the 3D printed object during 3D printing. For example, the melting temperature of the build plate 100 can be higher than 1000°C.

[0048] Although the shape depicted is a rectangular prism or cuboid with sidewalls extending vertically between top surface 110 and bottom surface 120, it should be noted that in other embodiments, build plate 100 can be some other suitable shape, such as a circular or trapezoidal prism, which can be used to implement the 3D printing techniques described herein.

[0049] In this example, the attachment of build plate 100 to a 3D printing device is represented by slots or holes 101 (e.g., bolt holes) at each corner of top surface 110. Structural protrusions (e.g., bolts or tabs) of the 3D printing device can be inserted into holes 101 to secure build plate 100 in place during 3D printing. Although holes 101 are shown at each corner of top surface 100, it should be understood that, depending on the embodiment, build plate 100 can include holes 101 and / or protrusions at any suitable location on top surface 110, bottom surface 120, and / or other surfaces of build plate 100 to facilitate attachment to a 3D printing device. In some embodiments, holes 101 may be included on bottom surface 120, but not on top surface 110, to prevent 3D printed powdered metal from falling into holes 101. In some embodiments, protrusions (e.g., bolts or tabs) may be used instead of holes 101. For example, the protrusions may be coupled to holes of a 3D printing device.

[0050] Build plate 100 includes a mortise or recess 140 extending through the center thereof. Recess 140 includes a bottom surface and inclined or angled sidewalls 131 such that a top surface perimeter 141 of recess 140 is less than a bottom surface perimeter 142 of recess 140. In other words, the recess tapers toward the top of build plate 100. While the depicted example shows four inclined sidewalls such that bottom surface perimeter 142 is greater than top surface perimeter 141 along each side or dimension, the number of inclined sidewalls 131 may be one or more such that bottom surface perimeter 142 is greater than top surface perimeter 141 along at least one side. As further described below, recess 140 may be filled with a metal or metal alloy having a lower melting temperature to form a solid metal structure that provides a thermally decomposable surface for building a 3D printed object. After the solid metal structure solidifies, the inclined sidewalls 131 may provide a locking mechanism to prevent the metal from lifting during the powder bed fusion process. The sloped sidewalls 131 may be used as a standalone solution to prevent metal lifting during 3D printing, or may be used in conjunction with other securing features described further below.

[0051] like Figure 1C As depicted, sidewall 131 can be inclined at an angle θ relative to a perpendicular line from the top surface of the recess to the bottom surface of the recess. In some embodiments, θ can be from 5° to 60°, from 5° to 45°, from 15° to 45°, or from 15° to 30°. In some embodiments, the inclination angle can be adjusted to optimize the tradeoff between sidewall inclination and maximizing part build surface area.

[0052] Extending through its bottom surface 120, the recess 140 includes a pouring through-hole 155 and a plurality of air / venting through-holes 115. When pouring liquid metal in the pouring through-holes 155 to form a thermally decomposable metal structure, it may be advantageous to add one or more additional holes in the bottom of the cavity to function as air through-holes 115. These optional air through-holes 115 may be located within the interior perimeter of the recess 140 or at another location and extend through the bottom side of the mold so that air can escape when filling the pouring through-holes 155 with metal, preventing voiding in the solid metal structure 160 being formed.

[0053] In alternative embodiments, the recess 140 may include more than one pouring through hole 155. In alternative embodiments, the recess 140 may include one air through hole 115 or no air through hole 115.

[0054] In the example shown, the pouring through-holes 155 and the air through-holes 115 are each tapered (tapered) such that the radius or perimeter of the holes on the outer surface of the build plate (i.e., the bottom surface 120) is greater than the radius or perimeter of the holes on the inner surface of the recess. As depicted, the pouring through-holes 155 and / or the air through-holes 115 can taper at an angle Φ relative to the vertical. In some embodiments, Φ can be from 5° to 60°, from 5° to 45°, from 15° to 45°, or from 15° to 30°. As further described below, by tapering the holes in this manner, the metal structure in the recess 140 can be better stabilized during 3D printing.

[0055] The size of the pouring holes 155 and the air holes 115 can vary. A pouring hole 155 having a diameter of at least 1 cm may be large enough to introduce liquid metal into the cavity by pouring. The air holes 155 may be smaller, about 1 / 2 cm or less. Although the air holes 115 are shown to be smaller than the pouring holes 155, the air holes 115 may be larger. In some embodiments, multiple holes having the same or similar diameters may function as both pouring holes and air holes.

[0056] The recess 140 also includes a blind hole 116 present on the interior portion of the build plate 100. The blind hole 116 extends outward from the interior of the recess 140, but unlike the air holes 115 and the pouring holes 155, the blind hole 116 does not perforate through the exterior of the build plate. In this example, the blind hole 116 tapers so that the radius or circumference of the entry point of the blind hole located on the interior surface of the recess is smaller than the radius or circumference extending toward the exterior. In alternative embodiments, the recess 140 may include one blind hole 116, or no blind hole 116. In some embodiments, the blind hole 116 may taper at an angle relative to the vertical, which may be from 5° to 60°, from 5° to 45°, from 15° to 45°, or from 15° to 30°.

[0057] The recessed portion 140 (including the pouring through hole 155, the blind hole 116 and the air through hole 115) can be formed by any suitable machining process, such as by using a mortise and tenon machine, a metal lathe, a milling machine, a drilling machine, etc. For example, the recessed portion 140 can be formed by mortising solid metal blocks. According to the embodiment, the top surface perimeter 141, the bottom surface perimeter 142 and the depth of the recessed portion 140 can be optimized for the 3D printing equipment and process used by the build plate 100. For example, the cutout perimeter can be molded so that it does not interfere with the 3D printing equipment fixing mechanism (e.g., providing enough space for the hole 101) while providing a large enough surface area to form a 3D printed object. In some embodiments, sufficient depth can be provided to optimize cooling and provide deeper channels.

[0058] It should be understood that sidewall bevels, hole locations, and hole shapes other than those shown may be used. For example, in some embodiments, the shapes of the pouring holes 155, blind holes 116, or air holes 115 may be rectangular, square, or irregular. In addition, in some embodiments, one or more of these holes may not taper.

[0059] refer to Figure 1C-1D To form metal structure 160 in interior recess 140, liquid metal or metal alloy 165 is poured through pouring holes 155 extending from exterior bottom surface 120 to interior recess 140. Prior to pouring, build plate 100 may be inverted 180 degrees so that pouring holes 155 face upward, and build plate 100 may be placed on a smooth surface or cover 105, such as a graphite or granite plate. When placed, cover 105 extends at least beyond the edge of the top surface of recess 140.

[0060] A liquid 165 of a metal or metal alloy may be poured onto the lid 105 through the pouring through-holes 155 using a container 199, filling the recesses 140, which include the through-holes and blind holes. Prior to this step, the solid metal or metal alloy may be heated to above its solidus temperature to form the liquid 165. In this example, since the liquid 165 is added with the build plate 100 inverted, any unwanted accumulation (e.g., scum) may float to the top of the filled recess and settle, which ensures a clean metal or metal alloy surface is formed where 3D printing occurs.

[0061] When liquid 165 (e.g., liquid metal) is poured into recess 140 during the casting process, the metal can displace the air and fill the cavity. If the air does not escape during the casting process, voids will occur. Voids may be undesirable because they hinder the flow of heat directly through the solid metal structure 160, into the build plate 100 and continue downward through the 3D printing build chamber, and when heated by the laser during the 3D build process, the top of the solid metal structure may melt or deform, which will be further described below. Therefore, the presence of air through holes 115 can help eliminate unnecessary voids and ensure a stable, uninterrupted downward heat flow, which is necessary for the successful operation of 3D metal printing. In some embodiments, to further help air escape from the build plate 100, the build plate 100 can be tilted (e.g., 30 degrees, 45 degrees, or 60 degrees) when pouring liquid 165. Metal can enter through the lower half of the pouring through hole 155, while air escapes through the upper half of the same hole. This technique may be particularly useful where the build plate structure does not have air through holes 115 .

[0062] like Figure 1DAs depicted, after solidification, solid metal structure 160 occupies interior recess 140 of build plate 100 such that solid metal structure 160 contacts the bottom and sidewalls of the interior recess and lid 105, such as graphite or granite. In addition to these illustrated techniques for forming solid metal structure 160, other techniques may be employed. In some configurations, such as with a book mold, pouring holes may be located on one side of build plate 100, and build plate 100 may stand on the opposite side thereof during pouring of liquid metal. In this configuration, pouring holes may be located on a side surface of the build plate that is perpendicular to the side of the build plate that meets lid 105. In some configurations, liquid metal or metal alloy may be poured through the top surface of recess 140 from the opposite side. In this embodiment, lid 105 may cover any openings in the bottom surface of the build plate, or lid 105 may not be required if there are no openings in the bottom surface.

[0063] During pouring and cooling, a clamp or other retaining feature may be used to hold the build plate 100 in contact with the cover 105 (e.g., a smooth plate surface) during pouring and cooling. After the metal solidifies, the cover 105 is removed from contact with the build plate 100, exposing the smooth top surface of the solid metal structure 160, which then becomes the build surface during the fusion of the metal powder bed. The smooth top surface can be flush with the top surface of the build plate. The material of the cover 105 can be made of such a material that it does not adhere to the build plate 100, but can be mechanically fixed in place. To facilitate the removal of the cover 105 and ensure the formation of a smooth surface (e.g., a flat surface flush with the top edge of the recess of the build plate), the cover 105 can be made of such a material, for example, graphite, polytetrafluoroethylene, ceramic, copper, stainless steel, tool steel, tin, aluminum, non-stick metal, or some material that does not adhere to the liquid 165 before or after the liquid 165 solidifies.

[0064] In some embodiments, solid metal structure 160 is a solid metal or metal alloy having a melting point lower than the melting point of the material (e.g., metal) of unfilled build plate 100. The solidus temperature of the metal or metal alloy may be at least 30°C lower than the solidus temperature of build plate 100. In some embodiments, the difference in melting point may be more significant. For example, in some embodiments, the solidus temperature of the metal or metal alloy may be at least 50°C lower, 100°C lower, 200°C lower, 400°C lower, 600°C lower, 800°C lower, 1000°C lower, or even more than 1000°C lower than the solidus temperature of build plate 100.

[0065] In some embodiments, the solid metal structure 160 is a solid metal or metal alloy having a solidus temperature below 300°C. In some embodiments, its solidus temperature is between 50°C and 250°C. For example, the solid metal structure 160 can be a solder alloy, such as a tin alloy (e.g., 96.5Sn3Ag0.5Cu), a bismuth alloy (e.g., 58Bi42Sn), or an indium alloy (e.g., 52In48Sn). In some embodiments, the solid metal structure can include at least 90% indium. In some embodiments, the solid metal structure can be an InAg alloy. In other embodiments, the solid metal structure 160 can be a single element metal, such as tin, indium, bismuth, or others.

[0066] Figure 1E A 3D metal printing process according to an embodiment of the present disclosure is shown, which includes a 3D metal printing apparatus 500 that uses a metal powder bed 520 and a laser 400 to form a 3D printed object 600 on a build plate 100. Also shown is a build plate loading platform 510 and an optical component 410 for directing the output of the laser 400. The metal powder bed 520 may include aluminum, cobalt, copper, nickel, steel, stainless steel, titanium, vanadium, tungsten carbide, gold, bronze, platinum, silver alloys, cobalt-chromium alloys, refractory metals, combinations thereof, or some other suitable metal or metal alloy for forming the 3D printed object 600.

[0067] To prepare the apparatus 500 for printing, a build plate as described herein (e.g., build plate 100) may be placed in the apparatus 500 and secured to the build plate loading platform 510 by fasteners, with the build surface facing upward. The apparatus 500 may be loaded with metal powder and the chamber door may be closed. The chamber may then be filled with an inert gas such as nitrogen or argon to prevent oxidation during the printing process. In some embodiments, the 3D printing chamber and / or the build plate may be preheated at a temperature below the solidus temperature of the solid metal structure 160.

[0068] At the beginning of printing, a recoater blade or other component of the device 500 can deposit metal powder, including a solid metal structure 160, on the top surface of the build plate 100. The laser 400 or a series of lasers can then laser irradiate / sinter the deposited metal powder and metallurgically bond / weld the metal powder layer that will become the 3D printed object to the build surface of the solid metal structure 160. This process can be repeated layer by layer until printing is complete. The device 500 can include a lowering mechanism (e.g., as part of the platform 510) device to allow subsequent metal layers of the 3D printed object 600 to be formed. As the device and the build plate are lowered, layers of metal powder can be added to the top surface and one or more lasers can be used to selectively bond / sinter areas of the 3D printed object 600 below.

[0069] During 3D printing, the laser power, recoater blade speed, dwell time between layers, and other parameters may be adjusted to allow the molten powder to solidify between laser passes. The first 1-10 layers may be critical because these layers form an intermetallic layer between the solid metal structure 160 and the 3D printed object 600, securing the object to the build surface.

[0070] The heat generated by the laser 400 during 3D printing can increase the temperature of the solid metal structure 160. One problem this can cause is premature melting of the solid metal structure 160. To prevent the solid metal structure 160 from prematurely melting during 3D printing, the increase in temperature can be taken into account when selecting a suitable metal or metal alloy 160. In some embodiments, the power of the laser 400 can be reduced and / or other parameters can be adjusted when forming the lower layers of the 3D printed object 600 to prevent the solid metal structure 160 from overheating during 3D printing.

[0071] Another problem that may arise due to the heating of the metal by the laser and also due to the subsequent pauses between layers is the thermal expansion and contraction of the solid metal structure 160. This can cause the solid metal structure 160, which is the build surface, to lift up from the recessed portion of the build plate 100. This lifting is undesirable because it can cause errors in the overall height (Z-axis) of the 3D printed object 600. If the lifting is not uniform, additional errors can be created in the xy plane, causing the 3D printed object 600 to be built beyond the desired specifications.

[0072] As described herein, the build plate can be designed with various features to help secure the solid metal structure 160 within the internal recessed portion of the build plate to prevent lifting and build failure during 3D printing. In some embodiments, these features can be subtractive features formed by the recessed portion of the build plate 100. For example, as described above, the build plate 100 can include a recessed portion having an inclined sidewall 131, one or more tapered through holes (e.g., pouring through holes 155 and air through holes 115), and / or one or more tapered blind holes 116. The inclined sidewall 131 can provide a locking mechanism to prevent the solid metal structure from lifting during powder bed fusion. The tapering of the through holes or blind holes so that the radius or circumference of the hole decreases toward the top surface (i.e., the printing surface of the build plate 100) can also create a securing mechanism for the solid metal structure 160 formed by these holes.

[0073] Other subtractive fixation features may be used in place of or in addition to the subtractive fixation features depicted for build plate 100. For example, a groove may be formed on the interior bottom of recess 140 and / or sidewalls 131. Additionally, a tapered hole may be formed on at least one sidewall 131, where the taper may be such that the radius or circumference of the hole decreases from the interior to the surface of sidewall 131.

[0074] Other hole structures for fixing solid metal structures can be used instead of or in addition to the tapered through holes described herein.For example, in some embodiments, a countersunk or countersunk hole can be formed through the bottom surface or sidewalls of the recess. Figure 2A-2B A cross-sectional side view of an example of a build plate 200 using countersunk vias is shown. In this example, the recessed portion 140 of the build plate 200 includes a countersunk pouring via 146a and a countersunk air via 146b. Although not shown in this example, one or more countersunk blind holes may also be formed. The depicted countersunk vias may be formed by drilling holes from the bottom surface 120 of the build plate 200 to the recessed portion 140, with the radius of the entire hole being equal. Thereafter, a drill bit with a larger radius may be used to drill into the existing hole from a portion of the bottom surface 120 of the build plate 200 (e.g., through about 1 / 4, 1 / 3, 1 / 2, etc.) to form a countersunk hole. The countersunk drill bit may be straight or tapered, as long as the opening of the hole on the bottom of the build plate is larger than the opening of the hole on the bottom surface of the bottom of the internal recess. The countersunk feature on the bottom of the build plate prevents the solid metal structure 160 from lifting during 3D printing when the solid metal structure 160 is filled.

[0075] Features that help secure a solid metal structure within an interior recess of a build plate need not be limited to subtractive features (e.g., holes and grooves) present on the interior recess of a build plate, some of which extend partially or completely through the build plate metal toward the exterior surface of the build plate and / or through the exterior surface of the build plate. In some embodiments, there may be positive features such as lands on the interior surface of the recess. These features may be generated during the subtractive process of forming the lands. If the build plate itself is formed by additive manufacturing, the lands may be generated additively, and the lands may be generated passively relative to the lands. A combination of lands, grooves, and / or holes located on the interior surface of the recess may serve as anchor points to prevent lifting of the solid metal structure. These features, while originating from the interior portion of the recess, may extend through the build plate wall toward the exterior of the build plate, as is the case with subtractive holes and grooves. These subtractive features may extend outward into the sidewalls, or may extend outward into the bottom of the build plate.

[0076] Positive features (e.g., convex surfaces) originating from within a recess can extend inward and be completely contained within the recess cavity. To prevent interference during 3D printing, positive features can be designed to not protrude above the build surface once the cavity is filled with liquid metal (solidified into a solid metal structure).

[0077] More generally, the subtractive relief features and positive relief features designed into the interior of the recessed portion can be straight, tapered, dovetailed, or irregular. There can be one or more features. There can be multiple features of the same type or a combination of features, including a combination of convex surfaces, grooves, tapered or non-tapered holes. Features can be continuous or discontinuous. These features can be contained within the internal recessed portion or can extend partially or completely through the build plate toward the outer surface.

[0078] In some embodiments, one or more subtractive channels may extend along at least a portion of one of the sidewalls and / or bottom surfaces of the recessed area. In other embodiments, the channel may extend along the entire perimeter of the recessed cavity of the build plate. The channel may be dovetail-shaped. The dovetail channel may extend along the inner perimeter of the recessed portion 140 and partially protrude into the build plate toward the outer surface of the build plate. The dovetail direction may be such that the dovetail originates from the inside of the recessed portion at an angle arc that is less than the dovetail channel ends in the sidewall of the build plate. The smaller opening of the dovetail may be flush with the sidewall of the recessed cavity and extend outwardly toward the outer surface of the build plate through the build plate metal. The channel may be discontinuous or continuous and may extend along the entire perimeter of the bottom and / or side surface of the recessed portion, so that the smaller opening of the dovetail is flush with the bottom of the recessed cavity and extends downwardly through the build plate metal toward the outer bottom surface of the build plate. These channels can be used in place of other locking features or in conjunction with discontinuous locking features to enhance retention of solid metal structures during 3D printing and prevent lifting of the solid metal structure build plate surface.

[0079] Figure 3 A perspective view of an example of a build plate 300 implementing subtractive relief features and positive relief features according to some embodiments of the present disclosure is shown. As depicted, in addition to pouring holes 155, air holes 115, and blind holes 116, build plate 300 also includes two dovetail channels 143, each channel having alternating dovetail grooves along its length.

[0080] Figure 4A-4B Cross-sectional views are shown of additional examples of combinations of positive relief features 410 and subtracted relief features 420 that may be formed on a bottom surface or side surface of a build plate recess as described herein. Figure 4A Depicted are relief features prior to the recesses being filled with solid metal alloy. Figure 4B The relief feature is depicted after the recess is filled with solid metal or metal alloy 430 .

[0081] The relief features described herein may be created by computer numerical control (CNC), drilling machines, routers, additive manufacturing, or any other process that adds or removes metal or other material in order to create convex surfaces, recesses, holes, or other subtractive and / or positive features that serve as anchors for the solidified metal that provides the 3D printed build surface. Convex and recessed features may also be created by thermal spraying or by sandblasting on the interior bottom and sidewalls of the recess, respectively, and / or protrusions, recesses, or holes that are completely within the recess cavity or extend partially or completely outward to the bottom or sidewalls of the build plate.

[0082] When 3D printing is complete, the build plate 100 with the 3D printed object 600 can be removed from the 3D printing device 500. For example, Figure 1F An assembly is shown that includes a metal 3D printed object 600 that is metallurgically bonded to a build plate 100 after 3D printing is completed. The melting temperature of the metal or metal alloy used to form the 3D printed object 600 is higher than the melting temperature of the solid material 160. For example, similar to the build plate 100, the solidus temperature of the 3D printed object 600 can be at least 30°C higher than the solidus temperature of the metal or metal alloy. In some embodiments, the difference in melting points may be more significant. For example, in some embodiments, the solidus temperature of the 3D printed object 600 can be 50°C higher, 100°C higher, 200°C higher, 400°C higher, 600°C higher, 800°C higher, 1000°C higher, or even higher than 1000°C higher than the solidus temperature of the metal or metal alloy of the solid material 160. In some embodiments, the metal powder used to form the 3D printed object 600 may include aluminum, cobalt, copper, nickel, steel, stainless steel, titanium, vanadium, tungsten carbide, gold, bronze, platinum, silver alloys, cobalt-chromium alloys, refractory metals, combinations thereof, or some other suitable metal or metal alloy.

[0083] After 3D printing, the 3D printed object 600 is separated from the build plate. To this end, the assembly including the build plate and the 3D printed object can be heated (e.g., by placing the assembly in an oven) to a temperature above the solidus temperature of the lower melting temperature solid metal structure 160, thereby melting the metal and releasing the 3D printed object. In other embodiments, the 3D printed object 600 can be thermally separated from the solid metal 160 by a heat source other than an oven, such as a blowtorch, heated air, heated liquid, hot plate, laser, or any other suitable heat source that is sufficient to melt the solid metal structure 160, thereby releasing the 3D printed object 600. The molten metal or metal alloy can be collected in a container or collection device, while the remaining structure of the 3D printed object 600 and the build plate (including the recessed portion) remains solid. Before melting the solid metal structure, the assembly including the build plate and the 3D printed object can be placed in a container. The molten liquid metal or metal alloy can flow through the recessed portion and / or the through-holes of the build plate (if any) and enter the container. The collected metal or metal alloy may be reused to refill the recesses of the build plate or another build plate for future 3D printing operations.

[0084] During the removal process, the 3D printed object 600 can be fixed in place by a tool. For example, in one embodiment, the removal process includes at least the following steps: melting the solid metal structure while holding the 3D printed object; after melting the solid metal structure, removing the 3D printed object from the build plate; and after removing the 3D printed object from the build plate, positioning (e.g., tilting, inverting, rotating, etc.) the build plate to drain the liquid metal or metal alloy. After separating the 3D printed object 600, the object 600 can be post-processed (e.g., polished, reshaped, and / or ground) as needed.

[0085] In some embodiments, the process of removing the 3D printed object and / or collecting the molten metal or metal alloy can be incorporated into the compartment of the 3D printing component.

[0086] Although embodiments have thus far been described in the context of forming a solid metal structure 160 in a recess 140 of a build plate, the solid metal structure having one or more subtractive and positive features that stabilize the 3D printed build surface of the solid metal structure, it is contemplated that a pre-formed solid metal insert may be formed external to the build plate (e.g., in a casting mold) and subsequently inserted / secured into the recess of the build plate.

[0087] Although various embodiments of the disclosed technology have been described above, it should be understood that they are presented by way of example only and are not intended to be limiting. Similarly, various schematic diagrams may depict example architectures or other configurations of the disclosed technology to aid in understanding the features and functions that may be included in the disclosed technology. The disclosed technology is not limited to the example architectures or configurations shown, but rather various alternative architectures and configurations may be used to implement the desired features. In addition, with respect to flow charts, operating instructions, and method claims, unless the context dictates otherwise, the order of steps presented herein should not mandate that the various embodiments implement the described functions in the same order.

[0088] Although the disclosed technology is described above in various exemplary embodiments and implementations, it should be understood that the applicability of various features, aspects, and functions described in one or more individual embodiments is not limited to the specific embodiments described therewith, but can be applied to one or more other embodiments of the disclosed technology, either alone or in various combinations, whether or not these embodiments are described, and whether or not these features are presented as part of the described embodiments. Therefore, the breadth and scope of the technology disclosed herein should not be limited by any of the exemplary embodiments described above.

[0089] The terms and phrases used in this document and their variations, unless otherwise expressly stated, should be understood as open-ended and not restrictive. As examples of the foregoing: the term "including" should be understood as "including, without limitation" or similar meanings; the term "example" is used to provide an illustrative example of the item being discussed, rather than an exhaustive or limiting list thereof; the term "a" should be understood as "at least one", "one or more" or similar meanings; adjectives such as "conventional", "traditional", "normal", "standard", "known", and terms of similar meaning should not be understood as limiting the items described to items available in a specific time period or at a specific time, but should be understood to include conventional, traditional, normal or standard technologies that may be available or known at any time now or in the future. Similarly, when this article refers to technologies that are obvious or known to a person of ordinary skill in the art, such technologies include technologies that are obvious or known to a skilled person now or in the future.

[0090] In some cases, the appearance of broad words and phrases such as "one or more," "at least," "but not limited to," or other similar phrases should not be understood as intending or requiring the use of the narrower case where such broad phrase may not exist.

[0091] In addition, the various embodiments described herein are described in the form of exemplary block diagrams, flow charts, and other illustrations. As will be apparent to one of ordinary skill in the art upon reading this document, the illustrated embodiments and their various alternatives may be implemented without limitation to the illustrated examples. For example, the block diagrams and their accompanying descriptions should not be construed as prescribing a particular structure or configuration.

[0092] It should be understood that all combinations of the aforementioned concepts (as long as these concepts are not mutually contradictory) are considered to be part of the inventive subject matter disclosed herein. In particular, all combinations of claim themes appearing in this disclosure are considered to be part of the inventive subject matter disclosed herein.

[0093] Although various embodiments of the disclosed technology have been described above, it should be understood that they are presented by way of example only and are not intended to be limiting. Similarly, various schematic diagrams may depict example architectures or other configurations of the disclosed technology to aid in understanding the features and functions that the disclosed technology may include. The disclosed technology is not limited to the example architectures or configurations shown, but rather various alternative architectures and configurations may be used to implement the desired features. In addition, with respect to flow charts, operating instructions, and method claims, unless the context otherwise dictates, the order in which the steps are presented herein should not mandate that the various embodiments implement the described functions in the same order.

[0094] Although the disclosed technology is described above in various exemplary embodiments and implementations, it should be understood that the applicability of various features, aspects, and functions described in one or more individual embodiments is not limited to the specific embodiments described therewith, but can be applied to one or more other embodiments of the disclosed technology, either alone or in various combinations, whether or not these embodiments are described, and whether or not these features are presented as part of the described embodiments. Therefore, the breadth and scope of the technology disclosed herein should not be limited by any of the exemplary embodiments described above.

[0095] The terms and phrases used in this document and their variations, unless otherwise expressly stated, should be understood as open-ended and not restrictive. As examples of the foregoing: the term "including" should be understood as "including, without limitation" or similar meanings; the term "example" is used to provide an illustrative example of the item being discussed, rather than an exhaustive or limiting list thereof; the term "a" should be understood as "at least one", "one or more" or similar meanings; adjectives such as "conventional", "traditional", "normal", "standard", "known", and terms of similar meaning should not be understood as limiting the items described to items available in a specific time period or at a specific time, but should be understood to include conventional, traditional, normal or standard technologies that may be available or known at any time now or in the future. Similarly, when this article refers to technologies that are obvious or known to a person of ordinary skill in the art, such technologies include technologies that are obvious or known to a skilled person now or in the future.

[0096] In some cases, the appearance of broad words and phrases such as "one or more," "at least," "but not limited to," or other similar phrases should not be understood as intending or requiring the use of the narrower case where such broad phrase may not exist.

[0097] In addition, the various embodiments described herein are described in the form of exemplary block diagrams, flow charts, and other illustrations. As will be apparent to one of ordinary skill in the art upon reading this document, the illustrated embodiments and their various alternatives may be implemented without limitation to the illustrated examples. For example, the block diagrams and their accompanying descriptions should not be construed as prescribing a particular structure or configuration.

[0098] It should be understood that all combinations of the aforementioned concepts (as long as these concepts are not mutually contradictory) are considered to be part of the inventive subject matter disclosed herein. In particular, all combinations of claim themes appearing in this disclosure are considered to be part of the inventive subject matter disclosed herein.

Claims

1. An additive manufacturing build plate, comprising a body having a recessed portion formed through a first surface of the body, the recessed portion comprising a bottom surface within the body and a sidewall extending to the bottom surface, wherein: The recess is configured to be filled with a metal or metal alloy in solid form, which provides a printing surface for forming a 3D object in a 3D printing device; and The recessed portion includes a locking mechanism configured to prevent the solid form of the metal or metal alloy from lifting during 3D printing in the 3D printing device.

2. The additive manufacturing build plate of claim 1, wherein: The locking mechanism includes the side wall; and At least one of the side walls is inclined so that the perimeter of the bottom surface of the recessed portion is greater than the perimeter of the top of the recessed portion.

3. The additive manufacturing build plate of claim 2, wherein the at least one sidewall is inclined at 5 to 45 degrees relative to a perpendicular line of the bottom surface of the recessed portion.

4. The additive manufacturing build plate of claim 1 , wherein: The locking mechanism includes a through hole formed through the bottom surface of the recess to a second surface of the body opposite to the first surface, the through hole having an opening that is larger at the second surface of the body than at the bottom surface of the recess. 5 . The additive manufacturing build plate of claim 4 , wherein the through hole tapers from the second surface of the body to the bottom surface of the recessed portion. 6 . The additive manufacturing build plate of claim 5 , wherein the through hole tapers at an angle of 5 to 45 degrees relative to a perpendicular line of the bottom surface of the recessed portion.

7. The additive manufacturing build plate of claim 4, wherein the through-hole is a countersunk hole or a countersunk hole.

8. The additive manufacturing build plate of claim 4, wherein the through-holes are pouring through-holes for filling the recesses with the metal or metal alloy in liquid form, which solidifies into solid form.

9. The additive manufacturing build plate of claim 4, wherein the through-holes are air holes configured to release air displaced by pouring the metal or metal alloy in liquid form in the recessed portion.

10. The additive manufacturing build plate of claim 1, wherein: The locking mechanism includes one or more blind holes formed through the bottom surface of the recess to the interior of the building plate, each of the one or more blind holes having an opening that is smallest at the bottom surface of the recess.

11. The additive manufacturing build plate of claim 1 , wherein the locking mechanism comprises a channel extending along at least a portion of the sidewall or the bottom surface of the recessed portion.

12. The additive manufacturing build plate of claim 11, wherein the channel comprises a plurality of dovetail grooves.

13. The additive manufacturing build plate of claim 1, wherein the locking mechanism comprises one or more subtractive features extending partially or completely through the body toward an outer surface of the body.

14. The additive manufacturing build plate of claim 13, wherein the locking mechanism further comprises one or more additive features present in the recessed portion, the one or more additive features comprising one or more positive topographic features.

15. The additive manufacturing build plate of claim 1 , further comprising: The metal or metal alloy is in solid form within the recess.

16. The additive manufacturing build plate of claim 15, wherein the solidus temperature of the metal or metal alloy is lower than the solidus temperature of the body and lower than the solidus temperature of the 3D object.

17. A method comprising: obtaining an additive manufacturing build plate comprising a body having a recessed portion formed through a first surface of the body, the recessed portion comprising a bottom surface within the body and sidewalls extending to the bottom surface; and A solid form of metal or metal alloy is formed within the recess having a printing surface for forming a 3D object in a 3D printing device, wherein the recess includes a locking mechanism configured to prevent the solid form of metal or metal alloy from lifting during 3D printing in the 3D printing device.

18. The method of claim 17, wherein: forming the metal or metal alloy in solid form comprises pouring the metal or metal alloy in liquid form into the pouring through-hole of the recessed portion, the metal or metal alloy in liquid form solidifying into solid form; and releasing the air expelled by the metal or metal alloy in liquid form through the air through-holes of the recessed portion, in: The metal or metal alloy in solid form extends into the pouring through-holes and the air through-holes, The locking mechanism includes the pouring through hole and the air through hole, and Prior to being filled with the metal or metal alloy in solid form, the pouring through-hole and the air through-hole each have an opening which is larger at the outer surface of the body than at the bottom surface of the recess.

19. The method according to claim 17, further comprising: After forming the metal or metal alloy in solid form, placing the additive manufacturing build plate in the 3D printing apparatus; and The 3D object is 3D printed on the printing surface, wherein the solidus temperature of the metal or metal alloy is lower than the solidus temperature of the additive manufacturing build plate and the 3D object, and the locking mechanism prevents lifting of the solid form of the metal or metal alloy due at least in part to an increase in the temperature of the metal or metal alloy during 3D printing.

20. A method comprising: Placing an additive manufacturing build plate in a 3D printing device, the additive manufacturing build plate comprising: a body having a recessed portion formed through a first surface of the body, the recessed portion comprising a bottom surface within the body and side walls extending to the bottom surface; and a metal or metal alloy in a solid form within the recess, wherein the solid form comprises a printing surface for forming a 3D object in the 3D printing apparatus, the metal or metal alloy having a solidus temperature lower than the solidus temperature of the additive manufacturing build plate and the 3D object, and the recess comprises a locking mechanism; and The 3D object is 3D printed on a printing surface of the solid form of the metal or metal alloy, wherein during 3D printing, the locking mechanism prevents lifting of the solid form of the metal or metal alloy due at least in part to an increase in temperature of the metal or metal alloy.

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