Method of Manufacturing Complex Shaped Component

[0001] This application claims priority to U.S. Provisional Application No. 61/706,839 filed Sep. 28, 2012.

[0002] This application relates to a method of making very complex shaped components in a manner that is reliable and simplified compared to the prior art.

[0003] Modern technology is called upon to make increasingly complex shaped components. As one example, gas turbine engines are often provided with an integrally bladed rotor. An integrally bladed rotor includes a hollow hub with a plurality of complex airfoil shapes extending radially outwardly of the hub.

[0004] Currently, integrally bladed rotors are often manufactured using hot forging technologies and then other technologies, such as milling, super abrasive machining, electro-chemical machining or other types of machining.

[0005] In addition, joining technologies, such as linear friction welding, may be utilized to secure the airfoils to the hub.

[0006] All of these processes are expensive and raise various challenges.

[0007] In addition, laser powder deposition has been utilized for deposing material on outer surfaces of the integrally bladed rotor. However, these techniques have not always provided an acceptable finished component.

[0008] In a featured embodiment, a method of forming a complex shaped part includes the steps of forming a polymer core by an additive manufacturing process, plating a metal about surfaces of the polymer core, removing the polymer core leaving hollows within a plating core, and depositing metal powder within the hollows.

[0009] In another embodiment according to the previous embodiment, a consolidation step occurs after the depositing of the metal powder into the hollows.

[0010] In another embodiment according to any of the previous embodiments, the consolidation process is a hot isostatic pressurization process.

[0011] In another embodiment according to any of the previous embodiments, the plating metal is a nickel based material.

[0012] In another embodiment according to any of the previous embodiments, the metal powder is also a nickel based material.

[0013] In another embodiment according to any of the previous embodiments, the complex shaped component is an integrally bladed rotor. The integrally bladed rotor has a hub and radially outwardly extending airfoils with the hollows that are formed in both the hub and the airfoils.

[0014] In another embodiment according to any of the previous embodiments, the plating occurs utilizing electroplating.

[0015] In another embodiment according to any of the previous embodiments, the polymer core is removed in a furnace.

[0016] In another embodiment according to any of the previous embodiments, the polymer core is melted, disintegrated or evaporated in the furnace.

[0017] In another embodiment according to any of the previous embodiments, the additive manufacturing process includes one of selective lithography analysis, selective laser sintering, fusion deposition of material or laminated object manufacturing.

[0018] In another embodiment according to any of the previous embodiments, a computer model of the complex shaped component is utilized to control the additive manufacturing process to form the polymer core.

[0019] In another embodiment according to any of the previous embodiments, dimensions of the polymer core are selected to be slightly smaller than dimensions of a desired final complex shaped part.

[0020] In another featured embodiment, an integrally bladed rotor has a hub with an inner bore and an outer surface. A plurality of airfoils extend radially outwardly of the outer surface. The airfoils and hub have radially outer surfaces and axially outer surfaces formed of a relatively thin metal plate layer. There is metal powder within hollows defined axially and radially inwardly of the plate layer.

[0021] In another embodiment according to the previous embodiment, the plate layer is a nickel based material.

[0022] In another embodiment according to any of the previous embodiments, the metal powder is a nickel based material.

[0031] An integrally bladed rotor 20 is illustrated in FIG. 1. As known, a hub 22 has an outer surface 24, and a plurality of airfoils 26 extend radially outwardly of the outer surface 24. The integrally bladed rotor 20 has a very complex shape and raises challenges to manufacture.

[0032] This application is directed to a method of making such an integrally bladed rotor in a reliable and relatively simple manner compared to the prior art. While an integrally bladed rotor is specifically disclosed, any number of other complex shaped parts will benefit from the teachings of this application.

[0033] FIG. 2A shows an initial step. A core 120 for forming an integrally bladed rotor is illustrated being only partially formed. A rapid prototyping process which utilizes additive manufacturing techniques is preferably utilized to form the core 120 from an appropriate polymer. A system 30 is shown schematically forming the core 120 from a polymer in such a rapid manufacturing process. Examples of such additive manufacturing processes include stereolithography (SLA), selective laser sintering, fused deposition modeling, laminated object manufacturing, or any other rapid manufacturing. As known, core 120 is being built up from layers. A CAD model of the desired integrally bladed rotor 20 can be utilized to drive these processes.

[0034] FIG. 2B shows the final core 220. Core 220 is manufactured to be of the general exact shape of the final integrally bladed rotor 20 and has outer surface 224, inner surface 222, and airfoils 226.

[0035] FIG. 2C shows a subsequent step. A plating process (shown schematically at 34) is utilized to plate an appropriate metal for forming the integrally bladed rotor onto a polymer. The process deposits a plating 326, 328 and 329 on the core 220. In fact, FIG. 2C is an oversimplification, in that the plating 328 would typically only be found in the portions of the outer surface 224 intermediate blades 226 on the core. Further, while a blade 226 is illustrated in FIG. 2C, in fact, the area 327 would also receive the plating to form a lateral outer wall of the airfoils for the final integrally bladed rotor. The thickness of the plating may be exaggerated to show the plating layers. However, the purpose of FIG. 2C is to make clear that the plating would cover the core 220, and that there would be plated metal on outer surfaces of the core 220 after the step 2C.

[0036] One metal which may be plated is an appropriate nickel or nickel alloy for forming the integrally bladed rotor 20. One possible process 34 would be electroplating. The plating thickness should be controlled and selected to achieve a structurally sound configuration after the step 2D.

[0037] In step 2E, hollows are illustrated at areas 500 and 501. To reach step 2E, the core 120 has been removed, as shown in FIG. 2D. In one example, the combined core and plating, as shown at 601, may be placed in a furnace 600 as shown schematically in FIG. 2D. The polymer forming the core 220 may be melted, disintegrated, or evaporated in any known manner.

[0038] What is left is a hollow configuration 320 as shown in FIG. 2E. A hollow structure 320 incorporates plating portions 326, 327, 328 and 329. Within this hollow structure 320 are hollows 500 within each of the airfoils and hollows 501 within the portions 328 and between the sides 329.

[0039] FIG. 2F shows a subsequent step. A metal powder fills the hollows. The metal powder is shown at 400 and 401, and may be deposited within the hollows in any known manner. A tool 610 is illustrated schematically delivering the metal powder into the hollows. The metal powder may be a nickel based powder that may be similar to the plating material. To ensure that powder fills in all areas of a hollow plated shell with complex shape configuration, a feeder spruce system may be included.

[0040] After step 2F, an integrally bladed rotor 520 may be subjected to some finishing operation. As an example, a hot isostatic pressure operation 601 is illustrated in FIG. 2G and provides very high pressure to the integrally bladed rotor 520. As known, in the operation 601, a container is typically filled with a fluid, and the fluid is pressurized to, in turn, pressurize the enclosed part 520. Powder out gassing may be utilized prior to the hot isostatic pressure operation.

[0041] Other finishing techniques, such as quasi-isostatic pressing or dynamic compaction can be utilized in place of the hot isostatic pressure.

[0042] A worker on this art may recognize that the CAD model initially utilized to form the core at step 2A may be adjusted to account for material shrinkage which might occur due to the consolidation operation.

[0043] An integrally bladed rotor 520 has a hub with an inner bore 54 and an outer surface 522, and a plurality of airfoils 523 extending outwardly of the outer surface. The airfoils 523 and hub have radially outer surfaces and axially outer surfaces formed of a relatively thin metal plate layer. There is metal powder within hollows defined axially and radially inwardly of the plated layer.

[0044] The plate layer may be a nickel based material, and the metal powder may be a nickel based material.

[0045] Although an embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.