Patent Application
20150224743
The present invention relates generally to an article manufactured using an additive method; and, more particularly, to an additively manufactured article including at least one substantially planar member that may define a surface of a cavity or undercut region contained within the finished article.
Additive manufacturing is a method by which an article is built one layer at a time using a specialized system. More specifically, a layer of powder material may be deposited onto a substrate and melted or sintered through exposure to a concentrated source of energy, such as a laser or electron beam, thereby consolidating the powder into a substantially solid form. Successive layers of the same or different powder material may be deposited and consolidated in this manner to produce an article. Each of these successive layers may also be bonded to the preceding layer by melting or sintering the surface region of the preceding layer through exposure to the same concentrated source of energy. The deposition of the powder material and movement of the energy source may be controlled by a computer to achieve a high degree of precision during the additive manufacturing sequence.
It is sometimes advantageous to manufacture an article containing cavities, undercut regions, or both using an additive manufacturing method, for reasons of reduced cost, reduced time, increased yield, or greater flexibility for customization of the articles thereby produced. However, downward facing surfaces of cavities and undercut regions typically require complex support structures to prevent these surfaces distorting during the deposition, consolidation, and joining of successive layers above. Furthermore, the complex support structures may be difficult and time consuming to remove, may degrade the surface finish of the downward facing surfaces following their removal, or may be inaccessible and therefore unable to be removed after the build is complete.
It is therefore desirable to form a cavity or undercut region in an additively manufactured article by including at least one substantially planar member that may support successive layers deposited during the additive manufacturing sequence and may also define at least one downward facing surface of the cavity or undercut region within the finished article. The planar member may be formed using an additive or non-additive manufacturing method that results in a high quality surface finish on the downward facing surface.
Embodiments of the present invention are summarized below. These embodiments are not intended to limit the scope of the claimed invention, but rather, these embodiments are intended only to provide a brief summary of possible forms of the invention. Furthermore, the invention may encompass a variety of forms that may be similar to or different from the embodiments set forth below, commensurate with the scope of the claims.
According to a first embodiment of the present invention, an article includes at least one first portion, wherein the at least one first portion is additively manufactured by depositing successive layers of one or more materials upon a surface such that a three dimensional structure is obtained; at least one second portion affixed the at least one first portion, the at least one second portion including a substantially planar member, and further including at least one bottom surface and at least one top surface; and at least one third portion, wherein the at least one third portion is additively manufactured by depositing successive layers of one or more materials upon the at least one top surface such that a three dimensional structure is obtained.
According to a second embodiment of the present invention, a method of manufacturing an article includes the steps of preparing at least one first portion by depositing successive layers of one or more materials upon a surface such that a three dimensional structure is obtained; preparing at least one second portion including a substantially planar member, and further including at least one bottom surface and at least one top surface, wherein the at least one second portion is affixed to the at least one first portion; and preparing at least one third portion by depositing successive layers of one or more materials upon the at least one top surface such that a three dimensional structure is obtained.
These and other features, aspects and advantages of the present invention may become better understood when the following detailed description is read with reference to the accompanying figures (FIGS), wherein like reference numerals refer to like parts throughout the various views unless otherwise specified.
Specific embodiments of the present invention are described below. This written description, when read with reference to the accompanying figures, provides sufficient detail to enable a person having ordinary skill in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. However, in an effort to provide a concise description of these embodiments, every feature of an actual implementation may not be described in the specification, and embodiments of the present invention may be employed in combination or embodied in alternate forms and should not be construed as limited to only the embodiments set forth herein. The scope of the invention is, therefore, indicated and limited only by the claims, and may include other embodiments that may occur to those skilled in the art.
The terminology used herein is for describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, an element or step recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural elements or steps, unless such exclusion is explicitly recited. Furthermore, references to “one embodiment” of the present invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.
Similarly, the terms “comprises”, “comprising”, “includes” and/or “including”, when used herein, 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. As used herein, the term “and/or” includes any, and all, combinations of one or more of the associated listed items.
Certain terminology may be used herein for the convenience of the reader only and is not to be taken as a limitation on the scope of the invention. For example, words such as “upper”, “lower”, “left”, “right”, “front”, “rear”, “top”, “bottom”, “horizontal”, “vertical”, “upstream”, “downstream”, “fore”, “aft”, and the like, when used without further limitation, merely describe the specific configuration illustrated in the various views. Similarly, the terms “first”, “second”, “primary”, “secondary”, and the like, when used without further limitation, are only used to distinguish one element from another and do not limit the elements described.
Referring now to the figures (FIGS), wherein like reference numerals refer to like parts throughout the various views unless otherwise specified,
In an exemplary embodiment, the composition of the first and third portions is Type 310 Stainless Steel alloy in powder form. The layers of material deposited using the additive manufacturing system have a thickness of about 20 microns to about 60 microns, resulting in a surface finish greater than about 10 microns, depending on the orientation of the surface relative to the build direction 222. The composition of the second portion is Type 304 Stainless Steel alloy in forged form and milled to a surface finish of about 3 to about 5 microns. Thus, the finish of the downward facing surface 232 is substantially higher than the finishes of the first and third portions.
The skilled practitioner will appreciate that other known methods for creating the high strength joint between the first and second portions may be used. In an embodiment, the second portion 230 may be metallurgically bonded to the first portion 220 using a brazing method, wherein a brazing material 250 may be placed in the gap 260 and an energy source may be applied to produce a high strength joint between the first and second portions. In another embodiment (not illustrated), the second portion 230 may be metallurgically bonded to the first portion 220 using a solid state method such as diffusion bonding, wherein the first and second portions are in direct contact and an energy source may be applied to produce a high strength joint between the first and second portions without the use of an additional element. In yet another embodiment (not illustrated), the second portion 230 may be metallurgically bonded to the first portion 220 using a solid state method such as friction welding or inertia welding, wherein the first and second portions are in direct contact and are caused to rapidly move relative to each other to produce a high strength joint between the first and second portions without the use of an additional element. In all embodiments requiring an energy source, the energy source may be the same as that used during the additive manufacturing of the first portion, or may be a different energy source.
If desired, the second portion 230 may be removed from the finished article using a thermal, chemical or mechanical process. In an exemplary embodiment, the second portion is coated with a high nickel brazing alloy, such as BNi-9, prior to placement upon and bonding to the first portion. The finished article is removed from the additive manufacturing system and placed in a brazing furnace having a suitable atmosphere and operating at about 2050 degrees F. (about 1121 degrees C.) for a suitable period of time to melt the coating, thereby releasing the second portion.
As described above, the present invention contemplates an additively manufactured article containing at least one cavity or undercut region, wherein at least one substantially planar member may be included to support successive layers deposited during the manufacturing sequence and may also define at least one downward facing surface of the cavity or undercut region within the finished article. The planar member may be formed using an additive or non-additive manufacturing method that results in a high quality surface finish on the downward facing surface.
Although specific embodiments are illustrated and described herein, including the best mode, those of ordinary skill in the art will appreciate that all additions, deletions and modifications to the embodiments as disclosed herein and which fall within the meaning and scope of the claims may be substituted for the specific embodiments shown. Similarly, other embodiments of the invention may be devised which do not depart from the spirit or scope of the present invention. Such other embodiments are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims. Likewise, the system components illustrated are not limited to the specific embodiments described herein, but rather, system components can be utilized independently and separately from other components described herein. For example, the components and assemblies described herein may be employed in any suitable type of gas turbine, aircraft engine, or other turbomachine having any suitable number and arrangement of stages, disks and shafts while still falling within the meaning and scope of the claims.
