We Claim:
1. An apparatus (10) for manufacturing a metallic component (C) or
portion thereof, comprising:
a build plate (26) including a build surface (36), a bottom surface (37) and an aperture (38) extending through the build plate (26) between the bottom surface (37) and the build surface (36);
an actuator (55) operable to translate a metallic component (C) with respect to the build plate (26) such that an end portion (64) of the metallic component (C) is positioned within the aperture (38) of the build plate (26) and below the build surface (36);
a seal (28) coupled within the aperture (38) of the build plate (26) and configured to engage the end portion (64) of the metallic component (C); and
an external heat control mechanism (30) positioned proximate to the bottom surface (37) of the build plate (26) and operable to form a predetermined temperature profile of the end portion (64) to prevent cracking of the component (C),
wherein the aperture (38) of the build plate (26), the seal (28), and the end portion (64) of the metallic component (C) cooperate to form a powder bed (60) configured to hold metallic powder (P) of a predetermined composition therein.
2. The apparatus (10) as claimed in claim 1, wherein the aperture (38) of the build plate (26) includes a first cross-section that defines an area that is not greater than 135% of an area defined by a second cross-section of the end portion (64) of the metallic component (C).
3. The apparatus (10) as claimed in claim 1, wherein the external heat control mechanism (30) is in a fixed positional relationship with respect to the build plate (26).
4. The apparatus (10) as claimed in claim 1, wherein the build plate (26) is non-metallic.
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5. The apparatus (10) as claimed in claim 1, further comprising a temperature feedback mechanism that controls the temperature of the end portion (64) via the external heat control mechanism (30) according to the temperature profile.
6. The apparatus (10) as claimed in claim 1, wherein the seal (28) seals off the aperture (38) with respect to at least the metallic powder (P) within the powder bed (60).
7. The apparatus (10) as claimed in claim 1, further comprising a directed energy source (80) operable to produce an energy beam suitable for fusing the metallic powder (P) in the powder bed (60) on the end portion (64) of the metallic component (C).
8. The apparatus (10) as claimed in claim 1, further comprising an airtight build enclosure (12) forming a substantially oxygen-free atmosphere, wherein at least the powder bed (60) is positioned within the substantially oxygen-free atmosphere.
9. The apparatus (10) as claimed in claim 1, further comprising:
a source of the metallic powder (P) of the predetermined composition; and
a transfer mechanism operable (20) to transfer metallic powder (P) from the source and substantially fill the powder bed (60) with the metallic powder (P).
10. The apparatus (10) as claimed in claim 1, wherein the external heat control mechanism (30) comprises at least one induction coil extending about the metallic component (C) when the metallic component (C) is positioned within the aperture (38), and wherein the build plate (26) is formed of an electrical insulating material that is operable to prevent the at least one induction coil from heating the build plate (26) to a sintering temperature of the metallic powder (P).
11. A method of manufacturing a component (C) or portion thereof, comprising:
translating a component with respect to a build plate (26) including a build
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surface (36), a bottom surface (37), an aperture (38) extending between the build surface (36) and the bottom surface (37), and a seal (28) coupled within the aperture (38) such that an end portion (64) of the component is in engagement with the seal (28) and positioned within the aperture (38) below the build surface (36);
depositing metallic powder (P) of a predetermined composition into the aperture (38) of the build plate (26) and over the seal (28) and the end portion (64) of the component (C);
directing a beam from a directed energy source (80) to fuse a portion of the deposited metallic powder (P) in a pattern to form a cross-sectional layer of the component (C) on the end portion (64); and
forming a temperature profile of the formed cross-sectional layer with an external heat control mechanism (30) positioned below the bottom surface (37) of the build plate (26) to prevent cracking of the component (C).
12. The method as claimed in claim 11, wherein translating the component (C), depositing the metallic powder (P), directing the beam from the directed energy source (80), and forming the temperature profile form a cycle, and wherein the method further includes performing the cycle a plurality of times to add a plurality of layers to the component (C).
13. The method as claimed in claim 11, wherein the build plate (26) is non-metallic, wherein the external heat control mechanism (30) comprises at least one induction coil extending about the metallic component (C), and wherein the seal (28) prevents the deposited metallic powder (P) from passing through the aperture (38).
14. The method as claimed in claim 11, wherein the aperture (38) of the build plate (26), the seal (28), and the end portion (64) of the metallic component (C) cooperate to form a powder bed (60) that holds the deposited metallic powder (P).
15. The method as claimed in claim 11, wherein the component (C) is
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a turbine blade, and wherein the formed cross-sectional layer is a portion of a tip portion of the turbine blade.
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