# US 10,865,647 B2 · Turbo-machine impeller manufacturing

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- Number: US 10,865,647 B2
- Document ID: US10865647B2
- Status: Granted
- Kind: B2
- Application number: 15/890,693
- Filed: 2018-02-07
- Published: 2018-07-26
- Granted: 2020-12-15
- Earliest claimed: 2012-02-23
- Assignees: Nuovo Pignone S.p.A.
- Applicants: Nuovo Pignone S.r.l.
- Inventors: Pierluigi Tozzi; Iacopo Giovannetti; Andrea Massini
- Web page: https://patentgrep.com/patent/US10865647B2

## CPC

- B22F 5/009: {of turbine components other than turbine blades (of turbine blades B22F5/04)}
- B22F 5/04: of turbine blades
- B22F 5/10: of articles with cavities or holes, not otherwise provided for in the preceding subgroups
- B22F 10/28: Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM]
- B22F 10/385: {Overhang structures}
- B22F 10/73: of powder
- B22F 12/10: Auxiliary heating means
- B22F 12/41: characterised by the type, e.g. laser or electron beam
- B23K 15/0006: {specially adapted for particular articles or work}
- B23K 15/0086: {welding for purposes other than joining, e.g. build-up welding}
- B23K 26/342: Build-up welding
- F01D 5/147: {Construction, i.e. structural features, e.g. of weight-saving hollow blades (F01D5/148, F01D5/16 and F01D5/20 take precedence; blade shape F01D5/141; blades with cooling or heating channels or cavities F01D5/18; heating, heat-insulating or cooling means on blades F01D5/18)}
- F01D 5/18: Hollow blades, {i.e. blades with cooling or heating channels or cavities (structure of hollow blades in general F01D5/147)}; Heating, heat-insulating or cooling means on blades
- F04D 29/023: {especially adapted for elastic fluid pumps}
- F04D 29/284: {for compressors}
- B22F 10/32: of the atmosphere, e.g. composition or pressure in a building chamber
- B22F 10/36: of energy beam parameters
- B22F 12/44: characterised by the configuration of the radiation means
- B22F 12/49: Scanners
- B23K 2101/001: {Turbines}
- F05D 2230/22: by sintering
- F05D 2230/31: Layer deposition
- F05D 2300/171: Steel alloys
- F05D 2300/174: Titanium alloys, e.g. TiAl
- F05D 2300/175: Superalloys
- F05D 2300/608: Microstructure
- Y02P 10/25: Process efficiency
- B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D)
- F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02)
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

A method of manufacturing a turbo-machine impeller, which includes a hub and a plurality of blades, using powder material in an additive-manufacturing process. The method includes: applying energy to the powder material by way of a high energy source, and solidifying the powder material. At least one bulky portion of the hub is irradiated such that the powder material solidifies in a lattice structure surrounded by an outer solid skin structure enclosing the lattice structure.

## Claims

### Claim 1

A method of manufacturing a turbo-machine impeller comprising a hub defining an impeller foot, a shroud and a plurality of blades using powder material in an additive-manufacturing process, the method comprising:
irradiating the powder material with a high energy source; and
solidifying the powder material to form the turbo-machine impeller,
wherein the powder material is irradiated such that the impeller foot and an inner portion of the shroud solidify, respectively, in a lattice structure surrounded by an outer solid skin structure enclosing the lattice structure.

### Claim 2 (depends on 1)

The method according to claim 1, further comprising:
depositing a first layer of powder material onto a target surface;
irradiating a first portion of the first layer of powder material with the high energy source and solidifying the first portion of powder material, the first portion corresponding to a first cross-sectional region of the turbo-machine impeller;
depositing a second layer of powder material onto the first portion;
irradiating a second portion of said second layer of powder material with the high energy source and solidifying the second portion of powder material, the second portion corresponding to a second cross-sectional region of the turbo-machine impeller, the first portion and the second portion being joined to one another;
depositing successive layers of powder material onto the previous portion and irradiating a portion of each successive layer to produce the turbo-machine impeller, further comprising a plurality of solidified, wherein each of the plurality of solidified layer portions correspond to a cross-sectional region of the turbo-machine impeller;
wherein at least some of the successive solidified layer portions respectively comprise at least one inner portion having a lattice structure surrounded by an outer solid skin.

### Claim 3 (depends on 1)

The method according to claim 1, wherein the high energy source comprises an electronic beam generator.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the high energy source comprises a laser source.

### Claim 5 (depends on 2)

The method according to claim 2, wherein the layers of powder material are deposited in a heated confinement structure.

### Claim 6 (depends on 2)

The method according to claim 2, further comprising controlling the temperature of the turbo-machine impeller after formation of the layer portions to avoid high temperature gradients in the turbo-machine impeller to minimize the residual stresses.

### Claim 7 (depends on 1)

The method according to claim 1, wherein the powder material is melted and solidified.

### Claim 8 (depends on 1)

The method according to claim 1, wherein the powder material is solidified by sintering.

### Claim 9 (depends on 1)

The method according to claim 1, wherein the high energy source is pulsed to generate the lattice structures.

### Claim 10 (depends on 1)

The method according to claim 1, further comprising the step of forming a lattice structure in more than one inner portion of the hub.

### Claim 11 (depends on 1)

The method according to claim 1, further comprising forming at least one aperture through the outer solid skin for removing un-solidified powder material.

### Claim 12 (depends on 1)

The method according to claim 1, further comprising removing un-solidified powder material from the lattice structures after all the layers of the turbo-machine impeller have been completely formed.

### Claim 13 (depends on 12)

The method according to claim 12, wherein the un-solidified powder material is removed by blowing or sucking a gaseous flow through the lattice structures.

### Claim 14

A method of manufacturing a turbo-machine impeller comprising a hub defining an impeller foot, a shroud defining an impeller eye, and a plurality of blades using powder material in an additive-manufacturing process, the method comprising:
irradiating the powder material with a high energy source; and
solidifying the powder material to form the turbo-machine impeller,
wherein the powder material is irradiated such that the impeller foot and the impeller eye solidify, respectively, in a lattice structure surrounded by an outer solid skin structure enclosing the lattice structure.