Patent Publication Number: US-2023142974-A1

Title: Additively manufactured object using mask over opening for coating

Description:
This application is a continuation of U.S. Application Ser. No. 17/073565, filed Oct. 19, 2020, currently allowed. 
    
    
     TECHNICAL FIELD 
     The disclosure relates generally to manufacturing objects, and more particularly, to additively manufacturing an object with a mask for an opening in an exterior surface of the object, for example, to prevent a coating from entering the opening. Remnants of support ligaments of the mask remain in the coating on the object. 
     BACKGROUND 
     Additive manufacturing (AM) includes a wide variety of processes of producing an object through the successive layering of material rather than the removal of material. As such, additive manufacturing can create complex geometries without the use of any sort of tools, molds or fixtures, and with little or no waste material. Instead of machining objects from solid billets of material, much of which is cut away and discarded, the only material used in additive manufacturing is what is required to shape the component. Accordingly, many industrial parts such as turbine rotor blades are preferably made by additive manufacturing. 
     Subsequent to formation by additive manufacturing, the objects may be further processed. In one example, the object may be exposed to a shot peening in which the surface of the object is bombarded with a peening material such as metal shot. In another example, the object may be coated with a protective layer to protect the underlying material thereof from the harsh environments in which the object is used. For example, a thermal barrier coating (TBC) may be applied to an outer surface of a turbine rotor blade to protect the blade from high temperatures during use. 
     Some objects may include openings in an exterior surface thereof that need to be protected during the post-print (or post-machining) processing. For example, a turbine rotor blade may include a variety of internal cooling circuits that vent to an exterior surface through cooling passages, i.e., openings in the exterior surface of the blade. The cooling passages may be provided to cool the internal structure where they are present, and/or create a cooling film across the outer surface of the blade. 
     A variety of mechanisms are employed to protect the openings. In some cases, removable material such as plugs may be provided in the openings to, for example, prevent them from being filled as a coating is applied thereover. The removable material blocks the coating from entering the openings, but increases manufacturing time and complexity because the removable material and/or the coating must ultimately be removed. For example, each opening must have the blocking material removed, which can be time consuming. Furthermore, the coating is typically applied over the blocking material, but needs to be removed from over the blocking material to expose the blocking material and/or the openings. Because the coating bridges over the blocking material, removal of the coating can cause cracking in the adjacent coating, e.g., a TBC, which may render the object unusable or require extensive additional processing. Removal of blocking material after a coating process can be especially challenging where the blocking material is seized with the object&#39;s material by the process. Other approaches employ shielding features that are welded on to protect the openings. In this latter case, the labor hours to cover every opening can be substantial. 
     BRIEF DESCRIPTION 
     An aspect of the disclosure provides an additively manufactured (AM) structure, comprising: an object including a body including an opening in an exterior surface thereof, the opening having a shape and a first area at the exterior surface of the body; a mask positioned over the opening and having the shape of the opening, the mask having a second area that is larger than the first area so as to overhang the exterior surface of the body about the opening; and a plurality of support ligaments, each support ligament coupled to the mask and the exterior surface of the body at a location adjacent to the opening to support a portion of the mask. 
     Further aspects of the disclosure provide an additively manufactured (AM) object, comprising: a body including an opening in an exterior surface thereof, the opening having a shape and a first area at the exterior surface of the body; a coating on the exterior surface of the body; and a plurality of ligament elements extending from the exterior surface of the body and through the coating adjacent the opening, each ligament element at least partially surrounded by the coating. 
     Another aspect of the disclosure provides a method, comprising: additively manufacturing an object, the object including: a body including an opening in an exterior surface of the body, the opening having a shape and a first area at the exterior surface of the body; a mask positioned over the opening and having the shape of the opening, the mask having a second area that is larger than the first area so as to overhang the exterior surface of the body about the opening; and a plurality of support ligaments, each support ligament coupled to the mask and the exterior surface of the body at a location adjacent to the opening to support a portion of the mask; applying a coating over the exterior surface of the body including the mask, wherein the coating does not span an entirety of a gap from an underside of the mask to the exterior surface of the body; and removing the mask, wherein a portion of at least one of the plurality of support ligaments is in an exterior surface of the coating. 
     Another aspect of the disclosure provides an additively manufactured (AM) structure, comprising: an object including a body including an opening in an exterior surface thereof, the opening having a shape and a first area at the exterior surface of the body; a mask positioned over the opening and having the shape of the opening, the mask having a second area that is larger than the first area so as to overhang the exterior surface of the body about the opening; and a plurality of support ligaments, each support ligament coupled to the mask and the exterior surface of the body at a location adjacent to the opening to support a portion of the mask, each support ligament having a circular or oval cross-sectional shape. 
     Another aspect of the disclosure provides an additively manufactured (AM) object, comprising: a body including an opening in an exterior surface thereof, the opening having a shape and a first area at the exterior surface of the body; a coating on the exterior surface of the body; and at least three ligament elements extending from the exterior surface of the body and through the coating adjacent the opening, each ligament element at least partially surrounded by the coating. 
     Another aspect of the disclosure provides an additively manufactured (AM) structure, comprising: an object including a body including an opening in an exterior surface thereof, the opening having a shape and a first area at the exterior surface of the body; a mask positioned over the opening and having the shape of the opening, the mask having a second area that is larger than the first area so as to overhang the exterior surface of the body about the opening; and a first plurality of support ligaments on one side of the opening and a second plurality of support ligaments on the other side of the opening, each support ligament coupled to the mask and the exterior surface of the body at a location adjacent to the opening to support a portion of the mask, wherein the plurality of support ligaments are breakable to remove the mask therefrom. 
     The illustrative aspects of the present disclosure are designed to solve the problems herein described and/or other problems not discussed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features of this disclosure will be more readily understood from the following detailed description of the various aspects of the disclosure taken in conjunction with the accompanying drawings that depict various embodiments of the disclosure, in which: 
         FIG.  1    shows a perspective view of an additively manufactured structure including a mask for an additively manufactured object, according to embodiments of the disclosure; 
         FIG.  2    shows a cross-sectional view of an additively manufactured structure including a mask, according to embodiments of the disclosure; 
         FIG.  3    shows a cross-sectional view of an additively manufactured structure including a mask with a coating thereon, according to embodiments of the disclosure; 
         FIG.  4    shows a perspective view of an additively manufactured structure including a mask, according to other embodiments of the disclosure; 
         FIG.  5    shows a perspective view of an additively manufactured structure including a mask, according to yet other embodiments of the disclosure; 
         FIG.  6    shows a cross-sectional view of an additively manufactured structure including a mask with an optional skirt, according to embodiments of the disclosure; 
         FIG.  7    shows a cross-sectional view of an additively manufactured structure including a mask with another optional skirt and a coating thereon, according to embodiments of the disclosure; 
         FIG.  8    shows a perspective view of an additively manufactured structure including a mask with an optional detachment member, according to embodiments of the disclosure; 
         FIG.  9    shows a partial cross-sectional view of an additively manufactured structure including a mask with an optional removal link in a support ligament, according to embodiments of the disclosure; 
         FIG.  10    shows a perspective view of an additively manufactured object with a coating, according to embodiments of the disclosure; and 
         FIG.  11    shows a cross-sectional view of removing a mask from an additively manufactured structure, according to embodiments of the disclosure. 
     
    
    
     It is noted that the drawings of the disclosure are not necessarily to scale. The drawings are intended to depict only typical aspects of the disclosure and therefore should not be considered as limiting the scope of the disclosure. In the drawings, like numbering represents like elements between the drawings. 
     DETAILED DESCRIPTION 
     As an initial matter, in order to clearly describe the current technology it will become necessary to select certain terminology when referring to and describing relevant machine components. To the extent possible, common industry terminology will be used and employed in a manner consistent with its accepted meaning. Unless otherwise stated, such terminology should be given a broad interpretation consistent with the context of the present application and the scope of the appended claims. Those of ordinary skill in the art will appreciate that often a particular component may be referred to using several different or overlapping terms. What may be described herein as being a single part or object may include and be referenced in another context as consisting of multiple components. Alternatively, what may be described herein as including multiple components may be referred to elsewhere as a single part or object. 
     It is often required to describe parts that are disposed at differing linear positions with regard to a position. The term “distal” refers to a locale or part of a thing that is more distant than the “proximal” locale or part of the same thing. For example, a distal end of a thing is farther away from a proximal end of the same thing. The terms thus provide general positioning relative to one another. In addition, several descriptive terms may be used regularly herein, as described below. The terms “first”, “second”, and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a”, “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. “Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not. 
     Where an element or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     Many iron-, cobalt-, and nickel- based superalloy materials traditionally used to fabricate a variety of industrial objects, e.g., the majority of combustion turbine components used in the hot gas path section of the combustion turbine engine, are insulated from the hot gas flow by coating the components with protective coatings in order to survive long term operation in an aggressive high temperature combustion environment. Protective coatings include, but are not limited to, thermal barrier coatings (TBC), bond coats, environmental barrier coatings (EBC), combinations thereof, and other coatings now known or hereinafter developed. Protective coatings can be produced by a multi-step process that includes coating surfaces requiring a protective coating for example with a bond coat and subsequent additional coats, dependent on the intended use of the turbine component and the environment associated with the use. 
     TBCs are highly advanced material systems. These coatings serve as protective coatings to insulate the components from large and prolonged heat loads by utilizing thermally insulating materials that can sustain an appreciable temperature difference between the load bearing alloys and the coating surface. In doing so, these coatings can allow for higher operating temperatures while limiting the thermal exposure of structural components, extending component life by reducing oxidation and thermal fatigue. TBCs are applied by various methods to a turbine component. Spraying is often used to apply a TBC (or other coating). Illustrative spray application processes include, but are not limited to, plasma spraying both in air and vacuum, cold spraying, electrostatic spraying, electron beam physical vapor disposition, chemical vapor deposition, thermal spraying, high-velocity oxy-fuel coating, physical vapor disposition, combinations thereof, and other spraying techniques now known or hereinafter developed. 
     One post processing/formation coating outcome that should be avoided is “bridging,” which is when subsequent post formation coating processes create a continuous layer from the surface of the part to the cover. Bridging can be caused when the TBC layer thickness is greater than the distance from the part surface to the cover. If too much coating material is present, the cover may be completely covered by TBC with no airgap remaining between it and the part surface. When the cover is removed, the adjacent TBC coating can crack or chip away, reducing its overall lifespan. Of course, for maintaining the expected function of the cooling holes, bridging should be kept controlled and eliminated, if possible. 
     Shadowing produces thin and poor quality coatings. The “shadowing” effect of spray (for example but not intended to limit the embodiments, TBC) happens as it deposits on the object while the line of sight of the plasma spray to the surface of the part is partially or totally blocked. The shadowing effect may be best visualized by placing an object in front of a light source and observing the shadow cast by that object. Light rays passing around the object is representative of spray being deposited, while the shadow cast by the object is representative of a void in the deposited spray. Thin coatings have higher than expected operating temperatures that can lead to premature failure. Coating particles that are deflected off a nearby structure do not adhere as well as particles deposited in direct line-of-sight that can cause premature failure. Thus, re-work may be needed to re-coat at locations (where coating is not rigorously bonded or adhered to the component or substrate), which may prolong processing time, require further resources, and may cause lost opportunity costs, and the like. 
     Openings (such as cooling holes) that are too small or too close to each other can be coated over as coating can build upon itself and completely block the holes. At these holes, coating can block openings. 
     As indicated above, the disclosure provides an additively manufactured (AM) structure including an object having a body including an opening in an exterior surface thereof. The opening has a shape and a first area at the exterior surface of the body. A mask may be positioned over the opening. The mask has the shape of the opening and a second area that is larger than the first area so as to overhang the exterior surface of the body about the opening. A plurality of support ligaments couple to the mask and the exterior surface of the body at a location adjacent to the opening to support respective portions of the mask. A coating can be applied to the object. The mask is removable from the object by breaking of the support ligaments, rather than machined off. The final additive manufactured object includes the body including the opening in the exterior surface, and the coating on the exterior surface of the body. A plurality of ligament elements, i.e., remnants of the support ligaments, extend from the exterior surface of the body and through the coating adjacent the opening. Each ligament element is at least partially surrounded by the coating. A detachment member may be provided to certain embodiments to allow easy removal of the mask from the object. A mask according to embodiments of the disclosure thus may protect each individual opening from bridging and clogging during the coating (or peening) processes in a highly customized manner, and allows for easy removal of the mask. The masks thus reduce the time to cover the openings prior to coating/peening, and reduces the time to clean out the openings. 
     Referring to  FIG.  1   , a perspective view of a mask  100  for an additively manufactured object  102  (hereinafter “object  102 ”) according to certain embodiments of the disclosure is illustrated. Mask  100  and object  102  may be formed using any appropriate additive manufacturing technique for the object material, and collectively may constitute an additive manufacture (AM) structure  103 . Additive manufacturing (AM) includes a wide variety of processes of producing an object through the successive layering of material rather than the removal of material. As such, additive manufacturing can create complex geometries without the use of any sort of tools, molds or fixtures, and with little or no waste material. Instead of machining components from solid billets of material, much of which is cut away and discarded, the only material used in additive manufacturing is what is required to shape the component. Additive manufacturing techniques typically include taking a three-dimensional computer aided design (CAD) file of the component, e.g., object  102  and mask  100 , to be formed, electronically slicing the component into layers, e.g., 18-102 micrometers thick, and creating a file with a two-dimensional image of each layer, including vectors, images or coordinates. The file may then be loaded into a preparation software system that interprets the file such that the structure, e.g., mask  100  and object  102 , can be built by different types of additive manufacturing systems. In 3D printing, rapid prototyping (RP), and direct digital manufacturing (DDM) forms of additive manufacturing, material layers, e.g., plastics or ceramics, are selectively dispensed to create the component, e.g., by laying the material layer after layer. In contrast, in metal powder additive manufacturing techniques, such as direct metal laser melting (DMLM) (also referred to as selective laser melting (SLM)), metal powder layers are sequentially melted together to form the part. More specifically, a metal power bed is provided within a processing chamber. A flow of a gas mixture is controlled within the processing chamber from a source of inert gas and a source of oxygen containing material. Fine metal powder layers are sequentially melted on the metal powder bed to generate the object, i.e., after being uniformly distributed using an applicator on a metal powder bed. Each applicator includes an applicator element in the form of a lip, brush, blade or roller made of metal, plastic, material, carbon fibers or rubber that spreads the metal powder evenly over the build platform. The metal powder bed can be moved in a vertical axis. As noted, the process takes place in a processing chamber having a precisely controlled atmosphere. Once each layer is created, each two dimensional slice of the component geometry can be fused by selectively melting the metal powder. The melting may be performed by a high powered melting beam(s), such as a 100 Watt ytterbium laser, to fully weld (melt) the metal powder to form a solid metal. The melting beam moves in the X-Y direction using scanning mirrors, and has an intensity sufficient to fully weld (melt) the metal powder to form a solid metal. The metal powder bed may be lowered for each subsequent two dimensional layer, and the process repeats until the component is completely formed. In one non-limiting example, mask  100  and object  102  may be formed by DMLM or SLM for a metal part, or 3D printing for a ceramic part. 
     In the  FIG.  1    embodiment, object  102  includes a body  104  including an opening  106  in an exterior surface  110  of object  102 . Any number of openings  106  may be provided. Object  102  may include any now known or later developed industrial part. In one non-limiting example, object  102  may include a turbine rotor blade that includes a variety of internal cooling circuits that vent to exterior surface  110  of the blade through cooling passages. The cooling passages may be provided to cool the internal structure where they are present, and/or create a cooling film across exterior surface  110  of object  102 . Although shown as in a planar exterior surface  110 , openings  106  may be positioned in a pedestal (not shown) in exterior surface  110  of the object extending from the surface of the object. 
     Opening(s)  106  may have any cross-sectional shape at exterior surface  110 , e.g., elliptical or oval ( FIG.  1   ), circular ( FIGS.  4 - 5   ), polygonal ( FIG.  5   ) (square, rectangular, trapezoidal, etc.), diffuser shaped ( FIG.  5   ), etc. Opening(s)  106  may extend into object  102  in any direction relative to exterior surface  110 . Opening(s)  106  may be positioned in any manner on exterior surface  110  of object  102 , e.g., in a line. Opening(s)  106  may be positioned across exterior surface  110  in a spaced manner, e.g., equidistant or not equidistant. Any number of masks  100  may be employed depending on, for example, whether all openings  106  are to be covered or just select openings  106 . Each opening  106  has an area, i.e., a cross-sectional area, at exterior surface  110  of body  104 . 
     A mask  100  is positioned over each opening  106 . Mask  100  has the shape of a respective opening  106 , i.e., same cross-sectional shape as opening  106 , at exterior surface  110 . Hence, mask  100  may be, for example, rounded such as elliptical or oval ( FIG.  1   ) or circular ( FIGS.  4 - 5   ), polygonal ( FIG.  5   ) (square, rectangular, trapezoidal, etc.), diffuser shaped, etc. As shown in  FIGS.  1 - 3   , mask  100 , however, has an area that is larger than the area of opening  106 , i.e., a cross-sectional area through it. In this manner, as shown best in the cross-sectional view of  FIG.  2   , mask  100  has an overhang  112  that extends over exterior surface  110  of body  104  outside and about opening  106 . Overhang  112  also acts to create a gap  116  from an underside  118  of mask  100  to exterior surface  110  of opening  106 . Underside  118  of mask  100  is spaced from exterior surface  110  of body  104  and over opening  106 . Although not necessary in all instances, overhang  112  may extend to a uniform distance (W 1 ) outwardly from an edge  114  of opening  106 . This distance is dependent on the thickness of the coating as well as other variables such as the spray angle with the surface, size of coating particles, etc. As shown in  FIG.  5   , masks  100  of different shapes to accommodate openings  106  of different shapes on the same object  102  may be employed, where desired. 
     AM structure  103  also includes a plurality of support ligaments  130  coupled to mask  100  and exterior surface  110  of body  104  at a location adjacent to opening  106 . Support ligaments  130  support mask  100  relative to exterior surface  110  of body  104 . That is, each support ligament  130  is coupled to mask  100  and exterior surface  110  of body  104  at a location adjacent to opening  106  to support a portion of mask  100 . As will be described, support ligaments  130  couples mask  100  to object  102  in a manner that allows easy removal of mask  100  from object  102 . Support ligaments  130  generally extend vertically (perpendicular) between exterior surface  110  and underside  118  of mask  100 ; however, some angling from vertical may be used. Support ligaments  130  may have any cross-sectional shape, e.g., circular ( FIG.  4   ), oval ( FIG.  1   ), polygonal ( FIG.  2   ) (square, rectangular, trapezoidal, etc.). In  FIGS.  1 - 3   , four support ligaments  130  are illustrated; however, any number of support ligaments  130  may be used, e.g., two or more. In certain embodiments, plurality of support ligaments  130  include at least one support ligament  130  on one side of opening  106 , and at least one support ligament  130  on other side of the opening  106 . In certain embodiments, as shown, pluralities of support ligaments  130  can be on either side of opening  106 . In certain embodiments, as shown, at least three support ligaments  130  are used. As will be further described, support ligaments  130  are formed sufficiently small to allow breaking to remove mask  100 , rather than having to machine the masks to remove them. It is noted that due to the limitations of certain additive manufacturing techniques, mask  100 , support ligaments  130  and object  102  may not be necessarily formed in the same orientation as illustrated. 
     Support ligaments  130  also define a gap spacing D 2  of gap  116 , defined between underside  118  of mask  100  and exterior surface  110  of object  102 . Gap  116  provides a number of advantages. In certain embodiments, as shown in  FIG.  2   , gap  116  has a dimension configured to prevent a peening material  132 , e.g., grit, metal shot, ice, pellets, sand, etc., from passing therethrough. In this case, a minimum dimension D 1  (e.g., diameter) of peening material  132  may be ascertained, and a gap spacing D 2  sized to be sufficiently smaller than minimum dimension D 1  to prevent peening material  132  from entering gap  116  and/or opening  106 . In this manner, masks  100  can prevent damage to openings  106  that may otherwise occur from impact by peening material  132 . In certain embodiments, as shown in the cross-sectional view of  FIG.  3   , gap spacing D 2  may also have a size configured to prevent a coating  134  applied over mask  100  from bridging from a respective mask member  100  to coating  134  over exterior surface  110  of object  102 . That is, a coating gap  136  exists in coating  134 . Gap spacing D 2  may be sized based on, for example, coating  134  material, application format, expected thickness, among other factors. As illustrated, while coating  134  coats object  102  and mask  100 , it fails to enter opening  106  and thus does not coat or fill openings  106 . Coating  134  also does not bridge mask  100  to object  102 . In this manner, when mask  100  is removed, coating  134  does not require breaking to remove the mask, which could cause cracking where coating  134  extends over object  102 . That is, there is no force applied to coating  134  on object  102 , and thus there is no possibility of cracking of coating  134  on object  102 . While gap spacing D 2  may vary depending on peening material  132  and/or coating  134 , in one non-limiting example, gap spacing D 2  may be between 0.88 millimeters (mm) to 1.4 mm (0.035 to 0.055 inches). This range of dimensions would, for example, prevent coating  134  having a thickness between 1.40 mm and 1.52 mm from bridging from masks  100  to object  102 , and would prevent 1.5 mm metal shot from lodging in gap  116  and impacting openings  106 . Other dimensions are possible. 
     Referring to  FIGS.  1  and  5   , AM structure  103  may also optionally include an overhang support element  140  coupled to overhang  112  and exterior surface  110  of body  104  to support overhang  112  during additive manufacture. Overhang support element  140  addresses a challenge with additive manufacturing of an object where new layers being formed do not have any underlying layers of material for support, and support ligament(s)  130  are not positioned in a way to provide underlying support. In this case, the new layers may not be held down and can curl upwardly. Overhang support element(s)  140  can be provided anywhere necessary, i.e., where curling of mask  100  is anticipated. In contrast to support ligaments  130 , overhang support element(s)  140  is more likely to be at a non-perpendicular angle relative to exterior surface  110  of body  104 . 
       FIG.  6    shows a cross-sectional view of AM structure  103  with a mask  100  according to an alternative embodiment. In this embodiment, mask  100  includes underside  118  spaced from the exterior surface  110  of body  104  and over opening  106 , as described previously. Gap  116  is thus present. In order to provide further protection for opening  106 , mask  100  may include a skirt  146  extending from underside  118  toward opening  106 . Skirt  146  is radially inward of support ligaments  130 . Skirt  146  may include a wall  148  extending downwardly from underside  118  of mask  100  that is continuous ( FIG.  6   ) or intermittent ( FIG.  7   ). Wall  148  may have a cross-sectional shape that matches that of opening  106 , e.g., ellipse, circle, etc., such that wall  148  follows the contour of edge  114  of opening  106 . Wall  148  of skirt  146  has a lower end  150  that is over opening  106 , and has a skirt spacing D 3  from exterior surface  110  of body  104 . Skirt pacing D 3  may be, for example, between 0.050 millimeters and 0.500 millimeters, which as shown in the cross-section of  FIG.  7   , prevents coating  134  from entering opening  106 . In some cases, lower end  150  may fuse to exterior surface  110 , but the bond is sufficiently weak to allow easy removal of mask  100  from body  104 . 
     Referring to  FIG.  8   , in certain embodiments, mask  100  may also include a detachment member  160  extending from mask(s)  100 . Detachment member  160  may include any structure capable of being engaged and manipulated to remove mask  100  from object  102  by breaking support ligament(s)  130 , and any overhang support elements  140 . Detachment member  160  may include, for example, a squared off end capable of grasping by a tool (not shown), e.g., channel lock pliers, adjustable wrench, etc. In addition thereto, or alternatively, detachment member  160  may include a tool receiving feature  162  therein configured to receive a tool (not shown) such as but not limited to a pry bar, screwdriver, channel lock pliers, adjustable wrench, etc. Tool receiving feature  162  may have any shape and/or size to prevent coating  134  ( FIGS.  3  and  7   ) from filling it. In any event, detachment member  160  is capable of manipulation using the tool or manually to apply a force that break support ligaments  130  and any overhang support elements  140 , thus allowing removal of mask  100 . Detachment member  160  may have any desired vertical height from mask  100 . 
     With further regard to support ligaments  130 , as shown in  FIG.  1   , each support ligament  130  may have uniform width W 2  along a length thereof that allows for its easy detachment, and thus mask  100  detachment, from object  102 . While support ligament(s)  130  have been illustrated herein as linear elements having a particular cross-section, it is understood that they may take a variety of structural forms not illustrated. That is, a uniform width W 2  is not necessary in all cases as it may be advantageous for support ligament(s)  130  to taper or narrow to foster breaking. For example,  FIG.  9    shows support ligament(s)  130  including a removal link  170  along a length of the support ligament(s)  130 . Removal link  170  includes a smaller width W 3 , i.e., lateral cross-sectional dimension, than the rest of support ligament  130 , creating a location of weakness in the support ligament. More specifically, a lower portion  172  of support ligament  130  is integrally coupled to object  102  and has a first width W 4 , and an upper portion  174  above lower portion  172  having a second width W 5  that is wider than first width W 4 . In various implementations, lower portion  172  may be embodied as and/or referred to as a pedestal, pin, base member, etc., with a distinct geometry as compared to upper portion  174 . Removal link  170  is positioned between lower and upper portions  172 ,  174 . The smaller width W 3  of removal link  170  makes it easier to break support ligament  130 , and allows for customization of where support ligament  130  breaks and how much of each support ligament  130  remains extending from exterior surface  110  of body  104 . Removal link  170  can take a variety of alternative forms, e.g., shapes, sizes, etc., not illustrated herein, but considered within the scope of the disclosure. In one non-limiting example, support ligament(s)  130  may have a width W 2  ( FIG.  1   ), W 4 , W 5  ranging from 0.125 mm to 1.000 mm and removal link  170  may have a width W 3  from 0.01 mm to 0.150 mm. The widths can vary depending on a large number of factors including but not limited to: object and mask material, size of object  102 , size of openings  106 , desired force to remove the mask, expected tools to be used, etc. 
     Mask  100  may be made of the same material as object  102 . Consequently, the material may depend on the object&#39;s application. In one embodiment, mask  100  and object  102  may be made of a metal, which may include a pure metal or an alloy. For example, where object  102  is a turbine blade, the metal may include practically any non-reactive metal powder, i.e., non-explosive or non-conductive powder, such as but not limited to: a cobalt chromium molybdenum (CoCrMo) alloy, stainless steel, an austenite nickel-chromium based alloy such as a nickel-chromium-molybdenum-niobium alloy (NiCrMoNb) (e.g., Inconel 625 or Inconel 718), a nickel-chromium-iron-molybdenum alloy (NiCrFeMo) (e.g., Hastelloy® X available from Haynes International, Inc.), or a nickel-chromium-cobalt-molybdenum alloy (NiCrCoMo) (e.g., Haynes 282 available from Haynes International, Inc.), etc. In another example, the metal may include practically any metal such as but not limited to: tool steel (e.g., H13), titanium alloy (e.g., Ti 6 Al 4 V), stainless steel (e.g., 316 L) cobalt-chrome alloy (e.g., CoCrMo), and aluminum alloy (e.g., AlSi 10 Mg). Alternatively, object  102  and mask  100  may be made of, for example, a plastic, a ceramic, combinations thereof, etc. As noted, mask  100  and object  102  may be made of additive manufacturing (e.g., DMLM, SLM, 3D printing, etc.) technique that will vary depending on the material. In any case, object  102 , support ligament(s)  130 , overhang support elements  140  and detachment member  160 , will include a plurality of integral material layers, created by the additive manufacturing. 
     As shown in  FIG.  10   , embodiments of the disclosure also include an additively manufactured (AM) object  102 , i.e., with mask  100  removed. Object  102  includes body  104  including opening  106  in exterior surface  110  thereof. As noted, opening  106  has a shape and a first area at exterior surface  110  of body  104 . Object  102  also includes coating  134  on exterior surface  110  of body  104 . In contrast to conventional AM objects, object  102  includes a plurality of ligament elements  180  extending from exterior surface  110  of body  104  and through coating  134  adjacent opening  106 . In certain embodiments, as shown, at least three ligament elements  180  (four shown in  FIG.  10   ) extend from exterior surface  110  of body  104  and through coating  134  adjacent opening  106 . Ligament elements  180  are remnants of support ligaments  130  that remain after mask  100  is removed. As illustrated, each ligament element  180  is at least partially surrounded by coating  134 . In certain embodiments, at least one ligament element  180  is on one side of opening  106 , and at least one ligament element  180  is on the other side of opening  106 . As shown in  FIG.  11   , where support ligaments  130  include removal link  170  as in  FIG.  9   , an outer portion  182  of each ligament element  180  at exterior surface  184  of coating  134  may have a smaller width W 3  than an inner portion  186  of each ligament element  180  within coating  134 . Outer portion  182  of ligament element  180  corresponds to removal link  170  ( FIG.  9   ) and inner portion  182  corresponds to lower portion  172  ( FIG.  9   ) of support ligament  130  ( FIG.  9   ). As shown in  FIG.  10   , where overhang support elements  140  are employed, object  102  may also include a portion  188  of overhang support element  140  ( FIG.  1   ) in exterior surface  184  of coating  134  after removing mask  100 . 
     Embodiments of the disclosure may also include a method for additively manufacturing object  102 . As shown in, for example,  FIG.  1   , the method may include additively manufacturing object  102 , as described herein. As noted, object  102  may include body  104  including opening  106  in exterior surface  110  of body  104 . Opening  106  has a shape and a first area at exterior surface  110  of body  104  that is mimicked by mask  100  positioned over opening  106 . That is, mask  100  has the shape of opening  106 . In non-limiting examples, opening  106  and mask  10  are elliptical ( FIG.  1   ) in shape and/or trapezoidal ( FIG.  3   ) in shape. As noted, mask  100  has a second area that is larger than the first area so overhang  112  of mask  100  extends over exterior surface  110  of body  104  about opening  106 . Object  102 , prior to removal of mask  100 , includes plurality of support ligaments  130 . Each support ligament  130  is coupled to mask  100 , i.e., underside  118  thereof, and exterior surface  110  of body  104  at a location adjacent to opening  106  to support a portion of mask  100 . 
     The additive manufacturing may also optionally include additively manufacturing overhang support element(s)  140  coupled to overhang  112  and exterior surface  110  to support the overhang. A portion  188  ( FIG.  10   ) of overhang support element  140  may be in exterior surface  184  of coating  134  after removing mask  100 . If desired, overhang support element  140  may be removed prior to coating. As shown in  FIG.  8   , the additive manufacturing may also optionally include additively manufacturing detachment member  160  extending from mask  100 . As noted, mask  100  includes underside  118  spaced from exterior surface  110  and over opening  106 . As shown in  FIGS.  6  and  7   , the additive manufacturing may also optionally include additively manufacturing skirt  146  extending from underside  118  toward opening  106 . Skirt  146  has lower end  150  having a skirt spacing D 3  from exterior surface  110  of body  104  and opening  106 . 
     The additive manufacturing may include any process described herein. For example, the additive manufacturing may include DMLM, including: providing a metal powder bed within a processing chamber; controlling a flow of a gas mixture within the processing chamber from a source of inert gas and a source of an oxygen containing material, the gas mixture including the inert gas and oxygen from the oxygen containing material; and sequentially melting layers of metal powder on the metal powder bed to generate object  102 . As DMLM is a well known additive manufacturing process, no further details or illustration are necessary. Other additive manufacturing processes may also be employed. 
     As shown in  FIGS.  3  and  7   , the method may further include applying coating  134  over exterior surface  110  of body  104  including mask  100 . In an optional step, the method may include, as shown in  FIG.  2   , applying peening material  132  to exterior surface  110  of body  104 , before applying the coating. In this case, peening material  132  has minimum dimension D 1 , and gap spacing D 2  from exterior surface  110  of body  104  is smaller than minimum dimension D 1  to prevent peening material  132  from entering opening  106 . Illustrative dimensions of D 1  and D 2  were previously stated. As noted, coating  134  does not span an entirety of coating gap  136  from underside  118  of mask  100  to exterior surface  110  of body  104 . Coating  134  may be applied using any technique appropriate for the coating. Illustrative spray application processes include, but are not limited to, plasma spraying both in air and vacuum, cold spraying, electrostatic spraying, electron beam physical vapor disposition, chemical vapor deposition, thermal spraying, high-velocity oxy-fuel coating, physical vapor disposition, combinations thereof, and other spraying techniques now known or hereinafter developed. 
       FIG.  11    shows a cross-sectional view of removing mask  100 . As noted, a portion of at least one of the plurality of support ligaments  130  ( FIG.  1   ), i.e., a ligament element  180 , is in exterior surface  184  of coating  134 . Mask  100  may be removed using any of a variety of techniques, but because of mask  100  arranged according to embodiments of the disclosure, it does not need to include machining. Removing mask  100  may include, for example, applying a force F to mask  100  or, where provided, detachment member  160  ( FIG.  8   ). Removing mask  100  may include, for example, cutting plurality of support ligaments  130 , e.g., with any mechanism for cutting or otherwise fatiguing the ligaments. As shown in  FIG.  11   , removing mask  100  may also include removing, where provided, skirt  146 . It is noted that no machining is required to remove mask  100 . 
     As indicated above, the disclosure provides an integrated opening mask  106  with the printed object  102  to prevent clogging and/or bridging of openings, e.g., cooling holes, by coating  134 , e.g., TBC or other post machining coating. Mask  100  has the shape of opening  106  at exterior surface  110  and is attached to exterior surface  110  via multiple support ligaments  130 , like table legs. Embodiments of the disclosure reduces the time required to mask the openings prior to coating and to clean out holes post-coating. 
     Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about,” “approximately” and “substantially,” are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Here and throughout the specification and claims, range limitations may be combined and/or interchanged; such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise. “Approximately,” as applied to a particular value of a range, applies to both end values and, unless otherwise dependent on the precision of the instrument measuring the value, may indicate +/−10% of the stated value(s). 
     The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present disclosure has been presented for purposes of illustration and description but is not intended to be exhaustive or limited to the disclosure in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the disclosure. The embodiment was chosen and described in order to best explain the principles of the disclosure and the practical application and to enable others of ordinary skill in the art to understand the disclosure for various embodiments with various modifications as are suited to the particular use contemplated.