Additive manufacturing method for making overhanging tabs in cooling holes
A method of forming an overhanging structure at a discharge end of a cooling hole that passes through a component. The method includes the step of using an additive manufacturing process to fuse material to a face to build up an edge of the discharge end of the cooling hole to form an overhanging tab.
1. A method of forming an overhanging structure at a discharge end of a cooling hole that passes through a component, the method comprising:
using an additive manufacturing process to fuse material to a face to build up an edge of the discharge end of the cooling hole to form an overhanging tab.
2. The method of claim 1 further comprising depositing powder in a recess located at the discharge end of the cooling hole; and
fusing the powder in a pattern corresponding to a layer of the structure.
3. The method of claim 2 further comprising repeating in a cycle the steps of depositing and fusing to build up the overhanging structure in a layer-by-layer fashion.
4. The method of claim 3 wherein the repeating cycle of depositing and fusing results in the component wall including both fused and un-fused powder, the method further comprising removing the un-fused powder.
5. The method of claim 2 wherein a multiple of separate subsequent layers is directly fused to the face.
6. The method of claim 5 further comprising fusing adjacent subsequent layers directly to the face.
7. The method of claim 2 further comprising forming a plug in the cooling hole and depositing powder on the plug.
8. The method of claim 7 further comprising fusing the powder such that unfused powder is left over at least a portion of the plug.
9. The method of claim 8 further comprising forming the overhanging tab by fusing subsequent layers such that unfused powder of each subsequent layer overlaps unfused powder of the previous layer.
10. The method of claim 1 further comprising building up an upstream edge of the discharge end.
11. The method of claim 1 wherein the component comprises a metal alloy.
12. The method of claim 1 wherein the powder comprises a metal alloy.
13. A method of forming a thin upstream edge of a cooling hole on a turbine component having a component wall with inner and outer surfaces, wherein the cooling hole passes through the component wall and fluidly connects the inner surface and the outer surface, the method comprising:
removing a portion of a discharge end of the cooling hole so as to form a first surface positioned between the outer surface and the cooling hole; and
using an additive manufacturing process to build a structure that extends away from the first surface toward the trailing edge of the discharge end of the cooling hole on the first surface.
14. The method of claim 13 further comprising depositing powder on the first surface; and
fusing the powder in a pattern corresponding to a layer of the structure.
15. The method of claim 14 further comprising repeating in a cycle the steps of depositing and fusing to build up the structure in a layer-by-layer fashion.
16. The method of claim 15 wherein the repeating cycle of depositing and fusing results in the component including both fused and un-fused powder, the method further comprising removing the un-fused powder.
17. The method of claim 14 further comprising forming a plug in the cooling hole and depositing powder in a layer that at least partially overlaps the plug.
18. The method of claim 17 further comprising fusing the powder in the layer such that the pattern leaves unfused powder over at least a portion of the plug.
19. The method of claim 18 further comprising repeating the steps of depositing powder and using until unfused powder layers extend above the outer surface of the component; and removing excess to fuse the material such that the outer surface of the component is smoothly extended over the cooling hole.