Additive fabricated object using a mask for coating openings

Abstract

Prevent clogging and / or bridging of openings by coating after coating and peening in additively manufactured products. The additively manufactured article (102) includes a body (104) including an opening in its outer surface (110), the opening (106) having a shape and a first area on the outer surface (110) of the body (104). A mask (100) is positioned above the opening (106). The mask (100) has the shape of the opening (106) and a second area greater than the first area so as to overhang the outer surface (110) of the body (104) around the opening (106). A plurality of support ligaments (130) are coupled to the mask (100) and the outer surface (110) of the body (104) adjacent the opening (106) to support a portion of the mask (100). A coating (134) can be applied to the article, and the mask (100) can be removed. The final additive manufacturing object includes a plurality of ligament elements (180) extending from the outer surface (110) of the body (104) adjacent the opening (106) through the coating (134), each ligament element (180) being at least partially surrounded by the coating (134).

Description

Technical Field

[0001] The present disclosure relates generally to the manufacture of articles, and more specifically to the additive manufacturing of articles that use a mask for an opening in an outer surface of the article (e.g., to prevent a film from entering the opening). Remnants of the support ligaments of the mask remain within the film of the article.

Background Art

[0002] Additive manufacturing (AM) includes a variety of processes for manufacturing articles by the successive layering of materials rather than by the removal of materials. As such, additive manufacturing can create complex shapes without the use of any tools, molds or fixtures and with little or no waste. Instead of machining an article from a solid billet of material, where most of the material is cut away and discarded, the materials used in additive manufacturing are only those required to form the part. Thus, many industrial components, such as turbine rotor blades, are preferably manufactured by additive manufacturing.

[0003] After formation by additive manufacturing, the article may be further processed. In one example, the article may be subjected to shot peening, which projects peening material, such as metal shot, onto the surface of the article. In another example, the article may be coated with a protective layer to protect the substrate material from the harsh environment in which the article is used. For example, a thermal barrier coating (TBC) may be applied to the outer surface of a blade to protect the turbine rotor blade from high temperatures during use.

[0004] Certain articles may include openings in their outer surfaces that need to be protected during post-forming (or post-machining) processing. For example, a turbine rotor blade includes various internal cooling circuits that communicate to the outer surface through cooling passages (i.e., openings in the outer surface of the blade). The cooling passages are provided to cool the internal structures in which they are located and / or to generate a cooling film flowing over the outer surface of the blade.

[0005] Various mechanisms are used to protect openings. In some cases, removable materials, such as plugs, are placed in the openings to prevent clogging during coating application. While removable materials prevent the coating from entering the opening, they increase manufacturing time and complexity because the removable materials and / or the coating must ultimately be removed. For example, the shielding material must be removed from each opening, which can be time-consuming. Furthermore, the coating is usually applied over the shielding material, but it must be removed from above the shielding material to expose the shielding material and / or the opening. Because the coating bridges over the shielding material, removing the coating may cause cracks in adjacent coatings (e.g., TBCs), rendering the item unusable or requiring extensive additional processing. Removing the shielding material after the coating process can be particularly difficult if the shielding material is trapped in the material of the item during that process. Another approach involves using shielding features that are welded to protect the openings. In this latter case, the labor time required to cover all openings can be considerable. [Overview of the Initiative]

[0006] One aspect of the present disclosure provides an additive manufacturing (AM) structure comprising: an article including a body having an opening on its outer surface, wherein the opening has a shape and a first area on the outer surface of the body; a mask positioned above the opening and having the shape of the opening, having a second area larger than the first area so as to protrude around the opening onto the outer surface of the body; and a plurality of support ligaments, each of which is bonded to the outer surface of the mask and the body at a position adjacent to the opening so as to support a portion of the mask.

[0007] Another aspect of the present disclosure provides an additively manufactured (AM) product comprising: a body having an opening on its outer surface, wherein the opening has a shape and a first area on the outer surface of the body; a coating on the outer surface of the body; and a plurality of ligament elements extending from the outer surface of the body adjacent to the opening through the coating, wherein each ligament element is at least partially surrounded by the coating.

[0008] Another aspect of the present disclosure provides a method, the method comprising the steps of additively manufacturing an article, the article comprising: a body having an opening on its outer surface, the opening having a shape and a first area on the outer surface of the body; a mask positioned above the opening and having the shape of the opening, the mask having a second area larger than the first area so as to project outwards from the outer surface of the body around the opening; a plurality of support ligaments, each support ligament bonded to the outer surface of the mask and the body at a position adjacent to the opening so as to support a portion of the mask; a step of applying a coating to the outer surface of the body including the mask, the coating not extending over the entire gap from the bottom surface of the mask to the outer surface of the body; and a step of removing the mask, the portion of at least one of the plurality of support ligaments being on the outer surface of the coating.

[0009] Exemplary embodiments of this disclosure are designed to solve problems described herein and / or not described herein.

[0010] Further details regarding the other features of this disclosure can be better understood by referring to the following detailed description in conjunction with the accompanying drawings illustrating various embodiments of this disclosure. [Brief explanation of the drawing]

[0011] [Figure 1] A perspective view of an additive manufacturing structure including a mask for an additively manufactured object, according to an embodiment of the present disclosure, is shown. [Figure 2] A cross-sectional view of an additive manufacturing structure including a mask, according to an embodiment of this disclosure, is shown. [Figure 3] This diagram shows a cross-sectional view of an additive manufacturing structure, including a mask with a coating, according to an embodiment of the present disclosure. [Figure 4] A perspective view of an additive manufacturing structure including a mask, according to another embodiment of the present disclosure, is shown. [Figure 5] A perspective view of an additive manufacturing structure including a mask, according to yet another embodiment of the present disclosure, is shown. [Figure 6] A cross-sectional view of an additive manufacturing structure including a mask having a skirt of an optional component, according to an embodiment of the present disclosure, is shown. [Figure 7] A cross-sectional view of an additive manufacturing structure, including a mask having a skirt and coating of another optional component, according to an embodiment of the present disclosure is shown. [Figure 8] A perspective view of an additive manufacturing structure, including a mask having detachable members for optional components, according to an embodiment of this disclosure is shown. [Figure 9] A partial cross-sectional view of an additive manufacturing structure, according to an embodiment of the present disclosure, is shown, which includes a mask having a removal link for an optional component within a support ligament. [Figure 10] A perspective view of a laminated product having a coating, according to an embodiment of this disclosure, is shown. [Figure 11] This diagram shows a cross-sectional view of mask removal from an additively manufactured structure according to an embodiment of the present disclosure.

[0012] Note that the drawings in this disclosure are not necessarily to scale. The drawings are illustrative of typical embodiments of this disclosure and do not limit the technical scope of this disclosure. In multiple drawings, the same reference numerals represent the same components. [Modes for carrying out the invention]

[0013] First, in order to clearly explain this technology, it is necessary to select terminology when referring to and describing the relevant mechanical parts. To the greatest extent possible, common terminology in the art will be used, in accordance with its ordinary meaning. Unless otherwise stated, such terminology should be interpreted broadly in the context of this application and the appended claims. It will be apparent to those skilled in the art that a certain part is often referred to using several different or overlapping terms. What is described in this specification as a single component or article may be described as consisting of multiple components in another context. Conversely, what is described in one part of this specification as comprising multiple components may be described elsewhere as a single component or article.

[0014] It is often necessary to describe parts that are located in different linear positions. The term "distal" means that a place or part of something is farther away than a "proximal" place or part of the same thing. For example, the distal end of something is farther away from the proximal end of the same thing. These terms define the approximate positional relationship between them. Furthermore, this specification uses several descriptive terms repeatedly, as described below. The terms "first," "second," and "third" are used interchangeably to distinguish one part from another and do not indicate the location or importance of individual parts.

[0015] The terms used herein are for the purpose of describing specific embodiments and do not limit the scope of the disclosure. In this specification, even if a term is described in the singular form, it means the plural unless the context makes otherwise clear. In this specification, the terms “equip” and / or “include” indicate the existence of a described feature, integer, step, operation, component, and / or part, and do not exclude the existence or addition of one or more other features, integers, steps, operations, components, parts, and / or groups thereof. The terms “optional” and “as appropriate” mean that the event or situation described following the term may or may not occur, and such description includes both cases in which the event or situation occurs and cases in which it does not.

[0016] When one component or layer is said to be “located,” “engaged,” “connected,” or “joined” to another component or layer, it may be directly located, engaged, connected, or joined to that other component or layer, or there may be an intervening component or layer. In contrast, when one component is said to be “directly located,” “directly engaged,” “directly connected,” or “directly joined” to another component or layer, there is no intervening component or layer. Other terms used to describe relationships between components (e.g., “between” and “directly between,” “adjacent” and “directly adjacent,” etc.) are interpreted similarly. The term “and / or” as used herein encompasses all combinations of one or more of those described.

[0017] Many iron-based, cobalt-based, and nickel-based superalloy materials, which have been commonly used in the manufacture of various industrial products, such as the majority of combustion turbine components used in the high-temperature gas path sections of combustion turbine engines, are shielded from high-temperature gases by coating the components with protective films to withstand long-term operation in harsh high-temperature combustion environments. Examples of protective films include, but are not limited to, thermal barrier coatings (TBCs), bond coats, environmental barrier coatings (EBCs), combinations thereof, and other currently known or future-developed films. Depending on the intended application of the turbine component and the environment associated with that application, protective films can be created by a multi-step process that includes coating the surface requiring protection with, for example, a bond coat and subsequent additional films.

[0018] Thermal barrier coatings (TBCs) are advanced high-temperature materials systems. These coatings function as protective coatings to thermally insulate components from large long-term heat loads by utilizing insulation materials that can withstand significant temperature differences between the load-bearing alloy and the coating surface. By doing so, these coatings can increase the operating temperature while limiting the thermal exposure of the structural components, and extend component life by reducing oxidation and thermal fatigue. TBCs are applied to turbine components in a variety of ways. Thermal spraying is widely used for the application of TBCs (or other coatings). Exemplary thermal spraying methods include, but are not limited to, air and vacuum plasma spraying, cold spraying, electrostatic spraying, electron beam physical vapor deposition, chemical vapor deposition, thermal spraying, high velocity oxy-fuel spraying, physical vapor deposition, combinations thereof, and other presently known or future-developed thermal spraying techniques.

[0019] One of the post-treatment / post-formation coating results to be avoided is "bridging", which occurs when a continuous layer from the surface of the member to the cover is produced in a subsequent post-formation coating process. Bridging may occur when the thickness of the TBC layer is greater than the distance from the surface of the member to the cover. If there is too much coating material, the cover may be completely covered with TBC, leaving no voids between the cover and the component surface. Removing the cover may crack or chip the adjacent TBC coating, potentially shortening the overall life. Of course, bridging should be suppressed and eliminated as much as possible to maintain the intended function of the cooling holes.

[0020] Shadowing produces a thin and poor-quality film. The "shadowing" effect of the sprayed particles (e.g., TBC, without limiting the embodiments) occurs when depositing the sprayed particles on an article while the line of sight of the plasma spraying to the surface of the member is partially or completely blocked. The shadowing effect can be best visualized by placing the article in front of a light source and observing its shadow. The light rays passing around the article represent the deposited sprayed particles, and the shadow of the article represents the void of the deposited sprayed particles. The thin film is higher than the intended operating temperature and may cause early failure. The film particles that deviate at a nearby structure do not adhere as well as the particles deposited in a straight line of sight and may cause early failure. Therefore, rework for recoating may be required at locations (where the film is not tightly bonded or adhered to the component or substrate), resulting in a longer processing time, additional resources being required, and possible losses in opportunity costs, etc.

[0021] Openings (such as cooling holes) that are too small or too close to each other may be covered because the film accumulates on them and completely blocks the holes. There is a risk that the film may block the openings in these holes.

[0022] As described above, this disclosure provides an additive manufacturing (AM) structure including an article having a body with an opening on its outer surface. The opening has a shape and a first area on the outer surface of the body. A mask can be positioned above the opening. The mask has the shape of the opening and a second area larger than the first area so as to project outwards from the outer surface of the body around the opening. Multiple support ligaments bond to the mask and the outer surface of the body at positions adjacent to the opening, supporting each portion of the mask. A coating can be applied to the article. The mask can be removed from the article by breaking the support ligaments rather than by machining. The final additively manufactured product includes a body with an opening on its outer surface and a coating on the outer surface of the body. Multiple ligament elements, i.e., remnants of the support ligaments, extend from the outer surface of the body through the coating adjacent to the opening. Each ligament element is at least partially surrounded by the coating. In certain embodiments, a detachable member may be provided to allow the mask to be easily removed from the article. The masks according to the embodiments of this disclosure thus protect individual openings from bridging and clogging during the coating (or peening) process in a highly customized manner and allow for easy removal of the masks. The masks reduce the time required to cover the openings before coating / peening and reduce the time required to clean the openings.

[0023] Referring to Figure 1, a perspective view of a mask 100 for an additively manufactured object 102 (hereinafter, "article 102") according to a particular embodiment of this disclosure is shown. The mask 100 and article 102 can be formed using any suitable additive manufacturing technique for the article material and together constitute an additively manufactured (AM) structure 103. Additive manufacturing (AM) involves various processes for manufacturing articles by the continuous layering of material rather than the removal of material. As such, additive manufacturing can create complex shapes without the use of any tools, molds, or fixtures, and with little to no waste. Instead of machining an article from a solid billet of material (where most of the material is cut off and discarded), the material used in additive manufacturing is only what is needed to create the part. Additive manufacturing technology typically involves obtaining a 3D computer-aided design (CAD) file of the part to be formed (e.g., article 102 and mask 100), electronically slicing the part into multiple layers (e.g., 18-102 μm thick), and creating a file containing a 2D image of each layer, including vectors, images, or coordinates. This file is then loaded into preparation software that interprets the file so that the structure (e.g., mask 100 and article 102) can be constructed by various types of additive manufacturing systems. Additive manufacturing in the forms of 3D printing, rapid prototyping (RP), and direct digital manufacturing (DDM) creates a part by selectively distributing material layers (e.g., plastic or ceramic) and stacking the material layers one by one. In contrast, metal powder additive manufacturing technologies such as direct metal laser melting (DMLM) (also called selective laser melting (SLM)) form a part by melting metal powder layers one by one. More specifically, a metal powder bed is provided within the processing chamber. The flow of the gas mixture is controlled within the processing chamber from an inert gas source and an oxygen-containing material source. After uniform distribution on the metal powder layer using an applicator, the fine metal powder layer is sequentially melted on the metal powder layer to produce an article. Each applicator contains applicator elements in the form of lips, brushes, blades, or rollers made of metal, plastic material, carbon fiber, or rubber, which spread the metal powder uniformly on the build platform. The metal powder bed can move in the vertical axis direction.As described above, the process is carried out in a processing chamber with a precisely controlled atmosphere. Once each layer is formed, each two-dimensional slice of the part shape can be fused by selective melting of the metal powder. The melting can be performed by a high-power melting beam, such as a 100W ytterbium laser, to sufficiently fuse (melt) the metal powder to form a solid metal. The melting beam is moved in the XY direction using a scanning mirror and has sufficient intensity to completely fuse (melt) the metal powder to form a solid metal. The metal powder bed is lowered for each subsequent two-dimensional layer, and the above process is repeated until the part is completely formed. In non-limiting examples, the mask 100 and article 102 may be formed by DMLM or SLM in the case of a metal part, or by 3D printing in the case of a ceramic part.

[0024] In the embodiment shown in Figure 1, article 102 includes a body 104 with openings 106 in the outer surface 110 of article 102. Any number of openings 106 may be provided. Article 102 may include currently known or future-developed industrial components. In a non-limiting example, article 102 may include turbine rotor blades with various internal cooling circuits that open to the outer surface 110 of the blade through cooling passages. Cooling passages may be provided to cool the internal structures in which they reside and / or to form a cooling film flowing over the outer surface 110 of article 102. Although shown as being on a flat outer surface 110, the openings 106 may be located on a base (not shown) of the outer surface 110 of article that extends from the surface of the article.

[0025] The openings 106 may have any cross-sectional shape on the outer surface 110, such as elliptical or egg-shaped (Figure 1), circular (Figures 4-5), polygonal (Figure 5) (square, rectangle, trapezoid, etc.), or diffuser shape (Figure 5). The openings 106 may extend in any direction relative to the outer surface 110 within the article 102. The openings 106 may be arranged in any way on the outer surface 110 of the article 102, for example, in a row. The openings 106 may be spaced on the outer surface 110, for example, at equal or unequal intervals. For example, any number of masks 100 can be used depending on whether all openings 106 are to be covered or only selected openings 106 are to be covered. Each opening 106 has an area (i.e., cross-sectional area) on the outer surface 110 of the body 104.

[0026] The mask 100 is positioned above each opening 106. The mask 100 has the same cross-sectional shape as each opening 106, i.e., the opening 106 on the outer surface 110. Therefore, the mask 100 can be, for example, elliptical or egg-shaped (Figure 1), circular (Figures 4-5), polygonal (Figure 5) (square, rectangle, trapezoid, etc.), or diffuser-shaped. However, as shown in Figures 1-3, the mask 100 has an area larger than the area of ​​the opening 106 (i.e., the cross-sectional area of ​​the opening). In this way, as is most clearly shown in the cross-sectional view of Figure 2, the mask 100 has an overhang 112 that extends outside and around the opening 106 on the outer surface 110 of the main body 104. The overhang 112 acts to form a gap 116 from the lower surface 118 of the mask 100 to the outer surface 110 of the opening 106. The mask 100 is spaced above the opening 106 from the outer surface 110 of the main body 104. Although not required in all cases, the overhang 112 may extend outward from the edge 114 of the opening 106 at a uniform distance (W1). This distance depends on the thickness of the coating and other variables, such as the spray angle relative to the surface and the particle size of the coating particles. If desired, different shaped masks 100 may be used to correspond to different shaped openings 106 on the same article 102, as shown in Figure 5.

[0027] The AM structure 103 also includes a plurality of support ligaments 130 that connect to the outer surface 110 of the mask 100 and the main body 104 at a position adjacent to the opening 106. The support ligaments 130 support the mask 100 against the outer surface 110 of the main body 104. That is, each ligament 130 connects to the mask 100 and the outer surface 110 of the main body 104 at a position adjacent to the opening 106 in order to support a portion of the mask 100. As will be described later, the support ligaments 130 connect the mask 100 to the article 102 so that the mask 100 can be easily removed from the article 102. The support ligaments 130 usually extend vertically (at a right angle) between the outer surface 110 and the lower surface 118 of the mask 100, but angles that are somewhat inclined from the vertical can also be used. The support ligaments 130 can have any cross-sectional shape, such as circular (Figure 4), elliptical (Figure 1), or polygonal (Figure 2) (square, rectangle, trapezoid, etc.). Figures 1 to 3 show four support ligaments 130, but any number of support ligaments 130 can be used, for example, two or more. In certain embodiments, the multiple support ligaments 130 include one or more support ligaments 130 on one side of the opening 106 and one or more support ligaments 130 on the opposite side of the opening 106. As will be further explained below, the support ligaments 130 are formed to be thin enough so that the mask 100 can be removed by breaking it without requiring machining to remove the mask. Note that, due to some limitations of additive manufacturing techniques, the mask 100, support ligaments 130, and article 102 may not necessarily be formed in the same orientation as shown in the figures.

[0028] The support ligament 130 defines the gap spacing D2 of the gap 116 between the lower surface 118 of the mask 100 and the outer surface 110 of the article 102. The gap 116 offers numerous advantages. In certain embodiments, as shown in Figure 2, the gap 116 has dimensions configured to prevent peening material 132 (e.g., grit, metal shot, ice, pellets, sand, etc.) from passing through. In this case, the minimum dimension D1 (e.g., diameter) of the peening material 132 should be determined, and the gap spacing D2 should be sufficiently smaller than the minimum dimension D1 to prevent the peening material 132 from entering the gap 116 and / or opening 106. Thus, the mask 100 can prevent damage to the opening 106 due to impact by the peening material 132. As shown in Figure 3, the gap spacing D2 may have dimensions configured to prevent bridging of the coating 134 applied on the mask 100 from each mask member 100 to the coating 134 on the outer surface 110 of the article 102. In other words, there is a gap 136 within the coating 134. The gap spacing D2 can be determined based on various factors, such as the material of the coating 134, the application format, and the expected thickness. As shown in the figure, the coating 134 covers the article 102 and the mask 100, but does not penetrate the opening 106, nor does it cover or fill the opening 106. The coating 134 does not crosslink the mask 100 to the article 102. Thus, when removing the mask 100, there is no need to destroy the coating to remove the mask, otherwise cracks may occur where the coating 134 extends over the article 102. In other words, since no force is applied to the coating 134 on the article 102, there is no risk of the coating 13 on the article 102 cracking. The gap spacing D2 may vary depending on the peening material 132 and / or coating 134, but in non-limiting examples, the gap spacing D2 may be 0.88 mm to 1.4 mm (0.035 to 0.055 inches). Dimensions within this range prevent, for example, a coating 134 with a thickness of 1.40 mm to 1.52 mm from bridging from the mask 100 to the article 102, and also prevent 1.5 mm metal shots from entering the gap 116 and impacting the opening 106. Other dimensions are also possible.

[0029] Referring to Figures 1 to 5, the AM structure 103 may appropriately include overhang support elements 140 that connect to the overhang 112 and the outer surface 110 of the main body 104 in order to support the overhang 112 during additive manufacturing. The overhang support elements 140 address the problem that occurs when a new layer formed during additive manufacturing of an article does not have a material layer that can support it from below, and the support ligament 130 is in a position where it cannot provide support from below. In this case, the new layer cannot be pushed down and may curl upward. The overhang support elements 140 can be provided at any necessary location, such as where bending of the mask 100 is expected. In contrast to the support ligament 130, the overhang support elements 140 are likely to be at an angle that is not perpendicular to the outer surface 110 of the main body 104.

[0030] Figure 6 shows a cross-sectional view of an AM structure 103 having a mask 100 according to another embodiment. In this embodiment, the mask 100 includes a lower surface 118 that is spaced apart from the outer surface 110 of the main body 104 and above the opening 106. A gap 116 exists. To further protect the opening 106, the mask 100 may include a skirt 146 extending from the lower surface 118 toward the opening 106. The skirt 146 is radially inward of the support ligament 130. The skirt 146 may include a wall 148 extending downward from the lower surface 118 of the mask, and the wall 148 may be continuous (Figure 6) or discontinuous (Figure 7). The wall 148 may have a cross-sectional shape (e.g., ellipse, circle, etc.) that matches the cross-sectional shape of the opening 106, so that the wall 148 follows the contour of the edge 114 of the opening 106. The wall 148 of the skirt 146 has a lower end 150 above the opening 106 and has a skirt gap D3 from the outer surface 110 of the main body 104. The skirt gap D3 can be, for example, 0.050 mm to 0.500 mm, and prevents the coating 134 from entering the opening 106, as shown in the cross-sectional view of Figure 7. In some cases, the lower end 150 may be fused with the outer surface 110, but the bond is weak enough so that the mask 100 can be easily removed from the main body 104.

[0031] Referring to Figure 8, in certain embodiments, the mask 100 may include a detachable member 160 extending from the mask 100. The detachable member 160 may include any structure that can be engaged and operated to remove the mask 100 from the article 102 by breaking the support ligaments and overhang support elements 140. The detachable member 160 may include a square end that can be gripped with a tool (not shown), such as channel locking pliers or an adjustable wrench. In addition / or, the detachable member 160 may include, but is not limited to, a tool holder 162 configured to receive a tool (not shown) such as a pry bar, screwdriver, channel locking pliers, or adjustable wrench. The tool holder 162 may have any shape and / or dimensions that prevent clogging with the coating 134 (Figures 3 and 7). In any case, the detachable member 160 can be operated in such a way that the mask 100 can be removed by applying force using a tool or by hand to break the support ligament 130 and any overhang support element 140. The detachable member 160 may have a desired vertical height from the mask 100.

[0032] Furthermore, with respect to the support ligaments 130, as shown in Figure 1, each support ligament 130 may have a uniform width W2 along its length so that it can be easily attached to and detached from the article 102, and therefore the mask 100 can also be attached and detached. The support ligaments 130 are shown as linear elements with a specific cross-section, but they can take on various structural forms not shown. That is, it may be advantageous to tapere or narrow the support ligaments 130 to make them more fragile, so a uniform width W2 is not always necessary. For example, Figure 9 shows a support ligament 130 with a removal link 170 along its length. The removal link 170 has a smaller width W3 (cross-sectional dimension) than the rest of the support ligament 130, creating a weak point in the support ligament. More specifically, the lower part 172 of the support ligament 130 is integrally connected to the article 102 and has a first width W4, while the upper part 174 above the lower part 172 has a second width W5 which is wider than the first width W4. In various embodiments, the lower part 172 may be embodied and / or referred to as a pedestal, pin, base member, etc., having a distinct shape from the upper part 174. The removal link 170 is positioned between the lower part 172 and the upper part 174. The small width W3 of the removal link 170 makes it easier to break the support ligament 130, and allows for customization of the position where the support ligament 130 breaks and how much of each support ligament 130 remains from the outer surface 110 of the main body 104. The removal link 170 can take various alternative forms (e.g., shape, dimensions, etc.) which are not shown in the figures but are within the technical scope of this disclosure. In non-limiting examples, the support ligament 130 may have widths W2 (Figure 1), W4, and W5 ranging from 0.125 mm to 1.000 mm, and the removal link 170 may have a width W3 ranging from 0.01 mm to 0.150 mm. The width is not limited and may vary depending on numerous factors, including the materials of the article and mask, the dimensions of the article 102, the dimensions of the opening 106, the force required to remove the mask, and the tools to be used.

[0033] The mask 100 can be made from the same material as article 102. Therefore, the material may depend on the application of the article. In one embodiment, the mask 100 and article 102 can be made from metals, including pure metals or alloys. For example, if article 102 is a turbine blade, the metal could be substantially any non-reactive metal powder, i.e., non-explosive or non-conductive powder, such as, but not limited to, cobalt-chromium-molybdenum (CoCrMo) alloy, stainless steel, austenitic nickel-chromium alloys such as nickel-chromium-molybdenum-niobium alloy (NiCrMoNb) (e.g., Inconel 625 or Inconel 718), nickel-chromium-iron-molybdenum alloy (NiCrFeMo) (e.g., Hastelloy® X, commercially available from Haynes International), or nickel-chromium-cobalt-molybdenum alloy (NiCrCoMo) (e.g., Haynes 282, commercially available from Haynes International). In another example, metals can refer to virtually any metal, for example, but are not limited to tool steel (e.g., H13), titanium alloys (e.g., Ti6Al4V), stainless steel (e.g., 316L), cobalt-chromium alloys (e.g., CoCrMo), and aluminum alloys (e.g., AlSi 10 Examples include Mg). Alternatively, article 102 and mask 100 may be manufactured from, for example, plastic, ceramic, or a combination thereof. As described above, mask 100 and article 102 may be manufactured by additive manufacturing technology (e.g., DMLM, SLM, 3D printing, etc.), but this may be changed depending on the material. In any case, article 102, support ligament 130, overhang support element 140, and detachable member 160 include multiple integral material layers created by additive manufacturing.

[0034] As shown in Figure 10, embodiments of the present disclosure also include additively manufactured (AM) articles 102, i.e., articles with the mask 100 removed. Article 102 includes a body 104 with an opening 106 on its outer surface 110. As described above, the opening 106 has a shape and a first area on the outer surface 110 of the body 104. Article 102 also includes a coating 134 on the outer surface 110 of the body 104. In contrast to conventional AM articles, article 102 includes a plurality of ligament elements 180 that extend from the outer surface 110 of the body 104 through the coating 134 adjacent to the opening 106. The ligament elements 180 are the remnants of the support ligament 130 that remain after the mask 100 is removed. As shown in the figure, each ligament element 180 is at least partially surrounded by the coating 134. In certain embodiments, one or more ligament elements 180 are located on one side of the opening 106, and one or more ligament elements 180 are located on the opposite side of the opening 106. As shown in Figure 11, if the support ligament 130 includes a removal link 170 as shown in Figure 9, the outer portion 182 of each ligament element 180 on the outer surface 184 of the coating 134 has a width W3 smaller than the inner portion 186 of each ligament element 180 inside the coating 134. The outer portion 182 of the ligament element 180 corresponds to the removal link 170 (Figure 9), and the inner portion 182 corresponds to the lower part 172 (Figure 9) of the support ligament 130 (Figure 9). As shown in Figure 10, if an overhang support element 140 is used, the article 102 may include a portion 188 of the overhang support element 140 (Figure 1) on the outer surface 184 of the coating 134 after the mask 100 has been removed.

[0035] Embodiments of this disclosure also encompass methods for additive manufacturing of article 102. For example, as shown in Figure 1, the method may include additive manufacturing of article 102 as described herein. As described above, article 102 may include a body 104 having an opening 106 on the outer surface 110 of the body 104. The opening 106 is mimicked by a mask 100 having a shape and a first area on the outer surface 110 of the body 104 and positioned above the opening 106. The mask 100 has the shape of the opening 106. In non-limiting examples, the opening 106 and the mask 10 are elliptical (Figure 1) and / or trapezoidal (Figure 3). As described above, the mask 100 has a second area larger than the first area, so the protrusion 112 of the mask 100 extends above the outer surface 110 of the body 104 around the opening 106. Article 102 includes a plurality of support ligaments 130 before the removal of the mask 100. Each support ligament 130 is coupled to the outer surface 110 of the main body 104 at a position adjacent to the mask 100 (i.e., its lower surface 118) and the opening 106, and supports a portion of the mask 100.

[0036] The additive manufacturing process may optionally include additive manufacturing of an overhang support element 140 that connects to the overhang portion 112 and the outer surface 110 to support the overhang portion. A portion 188 (Figure 10) of the overhang support element 140 may be on the outer surface 184 of the coating 134 after the mask 100 is removed. The overhang support element 140 may be removed before coating, if desired. As shown in Figure 8, the additive manufacturing process may optionally include additive manufacturing of a detachable member 160 that extends from the mask 100. As described above, the mask 100 includes a lower surface 118 that is spaced apart from the outer surface 110 and above the opening 106. As shown in Figures 6 and 7, the additive manufacturing process may optionally include additive manufacturing of a skirt 146 that extends from the lower surface 118 toward the opening 106. The skirt 146 has a lower end 150 that has a skirt spacing D3 from the outer surface 110 and the opening 106 of the main body 104.

[0037] Examples of additive manufacturing processes described herein include those described herein. For example, additive manufacturing may include DMLM, which involves supplying a metal powder bed into a processing chamber, controlling the flow of a gas mixture containing an inert gas and oxygen from an oxygen-containing material source within the processing chamber, and sequentially melting metal powder layers on a metal powder bed to produce an article. DMLM is a well-known additive manufacturing process and no further details or examples are needed. Other additive manufacturing processes may also be used.

[0038] As shown in Figures 3 and 7, the method may further include applying a coating 134 to the outer surface 110 of the main body 104, including the mask 100. As an optional step, the method may include applying a peening material 132 to the outer surface 110 of the main body 104, as shown in Figure 2, before applying the coating. In this case, the peening material 132 has a minimum dimension D1, and the gap D2 from the outer surface 110 of the main body 104 is smaller than the minimum dimension D1 so that the peening material 132 does not enter the opening 106. Exemplary dimensions of D1 and D2 have already been described. As stated above, the coating 134 does not extend to the entire coating gap 136 from the lower surface 118 of the mask 100 to the outer surface 110 of the main body 104. The coating 134 can be applied using any technique suitable for the coating. Examples of thermal spraying methods include, but are not limited to, atmospheric and reduced-pressure plasma spraying, cold spraying, electrostatic spraying, electron beam physical deposition, chemical deposition, thermal spraying, high-velocity flame spraying, physical deposition, combinations thereof, and other thermal spraying technologies that are currently known or may be developed in the future.

[0039] Figure 11 shows a cross-sectional view when the mask 100 is removed. As described above, one or more parts of the multiple support ligaments 130 (Figure 1), i.e., ligament elements 180, are located within the outer surface 184 of the coating 134. The mask 100 can be removed using any of the following techniques, but in the case of the mask 100 arranged according to the embodiments of this disclosure, machining is not required. Removal of the mask 100 includes, for example, applying a force F to the mask 100 or, if present, the detachable member 160 (Figure 8). Removal of the mask 100 may include, for example, cutting the multiple support ligaments 130 with, for example, any mechanism for cutting or fatiguering the ligaments. As shown in Figure 11, removal of the mask 100 may also include removing the skirt 146 if one is provided. Note that machining is not required to remove the mask 100.

[0040] As described above, the present disclosure provides an opening mask 106 integrated with the fabricated object 102 to prevent clogging and / or bridging of openings (e.g., cooling holes) by a coating 134 (e.g., TBC) or other post-processing coatings. The mask 100 has the shape of the opening 106 on the outer surface 110 and is attached to the outer surface 110 via a plurality of support ligaments 130, such as table legs. Embodiments of the present disclosure reduce the time required to mask the openings before coating and the time required to clean the holes after coating formation.

[0041] The approximate expressions used herein and in the claims are modifiers of quantities that are applied to indicate quantities that may vary within an acceptable range that does not alter the fundamental function to which the quantity relates. Therefore, values ​​modified with terms such as “approximately,” “about,” and “substantially” are not limited to their exact numerical value. In some cases, the approximate expression corresponds to the precision of the instrument used to measure the value. In this specification and in the claims, numerical ranges are combined and / or interchangeable, and such ranges are defined by their upper and lower limits and, unless otherwise evident from the context, encompass all subranges within those ranges. “Approximately” used for specific values ​​within a range may indicate ±10% of the stated numerical value, except where applied to the upper and lower limits and depending on the precision of the instrument used to measure the value.

[0042] In the following claims, the corresponding structures, materials, actions, and equivalents of the components identified by functional descriptions encompass all structures, materials, or actions that function in combination with other components specifically described in the claims. The descriptions in this disclosure are illustrative and explanatory, and are neither exhaustive nor limiting to the disclosed forms. Numerous modifications and variations will be apparent to those skilled in the art without departing from the technical scope and idea of ​​this disclosure. The embodiments of this disclosure have been selected and described to best illustrate the principles and practical uses of this disclosure and to enable those skilled in the art to understand the disclosures regarding various embodiments and various modifications suitable for specific uses. [Explanation of Symbols]

[0043] 100 masks 102 Additive-formed objects, articles 104 Main Unit 106 Aperture 110 Main body exterior 112 Overhang 116 Gap 130 Support Ligaments 140 Overhang support element 160 Detachable parts 180 Ligament Elements

Claims

1. A layered fabricated structure (103), wherein the layered fabricated structure (103) is An article (102) comprising a body (104) having an opening (106) on its outer surface (110), wherein the opening (106) has a shape and a first area on the outer surface (110) of the body (104), A mask (100) positioned above the opening (106) and having the shape of the opening (106), the mask (100) having a second area larger than the first area so as to protrude around the opening (106) onto the outer surface (110) of the main body (104), A plurality of support ligaments (130), each support ligament (130) being bonded to the outer surface (110) of the mask (100) and the main body (104) at a position adjacent to the opening (106) so as to support a portion (188) of the mask (100), A detachable member (160) extending from the mask (100) and A layered structure (103) comprising the above.

2. The additive manufacturing structure (103) according to claim 1, wherein the plurality of support ligatures (130) are breakable and the mask (100) can be removed therefrom.

3. The additive manufacturing structure (103) according to claim 1, further comprising a protruding portion support element (140) coupled to the protruding portion (112) and the outer surface (110) of the main body (104) in order to support the protruding portion (112) during additive manufacturing.

4. The additive manufacturing structure (103) according to claim 1, wherein the opening (106) and the mask (100) are either elliptical or trapezoidal in shape.

5. The additive manufacturing structure (103) according to claim 1, wherein the mask (100) includes a lower surface (118) spaced apart from the outer surface (110) of the main body (104) and above the opening (106), and further includes a skirt (103) extending from the lower surface (118) toward the opening (106), the skirt (146) having a lower end (150) defining the skirt spacing from the outer surface (110) of the main body (104).

6. The additive manufacturing structure (103) according to claim 5, wherein the skirt spacing is 0.050 mm to 0.500 mm.

7. The additive manufacturing structure (103) according to claim 1, wherein at least one support ligament (130) includes a removal link (170) along the length of at least one of the plurality of support ligaments (130), and the removal link (170) has a smaller cross-sectional dimension than at least one remaining portion of the plurality of support ligaments (130).

8. The additive manufacturing structure (103) according to claim 1, wherein the plurality of support ligaments (130) include one or more support ligaments (130) on one side of the opening (106) and one or more support ligaments (130) on the opposite side of the opening (106).

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