MANUFACTURE OF HOLLOW AEROFOIL

• US 20150252675A1
• Filed: 08/29/2014
• Published: 09/10/2015
• Est. Priority Date: 09/20/2013
• Status: Active Grant

• Current Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Original Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Inventors: RADOMSKI, Steven Aleksy
• Granted Patent: US 9,771,807 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B23K 13/01 by induction heating
• CPC Class Codes: B23K 20/002 specially adapted for particular articles or work B23K20/129 takes precedence
• CPC Class Codes: B23K 20/02 by means of a press ; Diffusion bonding B23K20/001, B23K20/04 take precedence
• CPC Class Codes: B23K 20/16 with interposition of special material to facilitate connection of the parts, e.g. material for absorbing or producing gas
• CPC Class Codes: B23K 2101/001 Turbines
• CPC Class Codes: B23P 15/04 turbine or like blades from several pieces
• CPC Class Codes: 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
• CPC Class Codes: 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
• CPC Class Codes: F05D 2220/32 in gas turbines
• CPC Class Codes: F05D 2230/10 by removing material
• CPC Class Codes: F05D 2230/236 Diffusion bonding
• CPC Class Codes: F05D 2230/51 in a modular way, e.g. using several identical or complementary parts or features
• CPC Class Codes: F05D 2230/60 Assembly methods
• CPC Class Codes: F05D 2230/90 Coating; Surface treatment manufacture with deposition of material F05D2230/30
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft
• CPC Class Codes: Y10T 29/49337 Composite blade

Abstract

A method of manufacturing a hollow aerofoil component (100) for a gas turbine engine (10) comprises using a capping panel (200) to cover a pocket (310) in a pocketed aerofoil body (300). During manufacture, a mandrel (400) is provided to support the capping panel (200) in the correct position. This ensures that the outer surface of the capping panel (200) is located as accurately as possible. This means that the capping panel (200) can be made to be as thin as possible, which in turn reduces weight and material wastage. Remotely detectable elements (700) may be provided to the mandrel (400) to enable the location of the pocket (310) to be accurately determined from outside the aerofoil (100).

Claims

1. A method of manufacturing a hollow aerofoil comprising:

providing a pocketed aerofoil body having an open pocket formed in a surrounding hollowed surface;

placing a temporary mandrel into the pocket of the pocketed aerofoil body;

locating a capping panel over the pocketed aerofoil body and temporary mandrel, the capping panel having an inner surface and an opposing outer surface;

joining a first region of the inner surface of the of the capping panel to the surrounding hollowed surface of the pocketed aerofoil body so as to form the hollow aerofoil; and

removing the temporary mandrel from the hollow aerofoil after the step of joining, wherein

the temporary mandrel is shaped so as to support the capping panel over a second region of its inner surface during the joining, such that the outer surface of the capping panel forms a desired aerodynamic surface of the hollow aerofoil.

2. A method of manufacturing a hollow aerofoil according to claim 1, wherein the temporary mandrel comprises at least one detectable element whose location can be detected remotely.

3. A method of manufacturing a hollow aerofoil according to claim 2, wherein the temporary mandrel comprises at least three such detectable elements.

4. A method of manufacturing a hollow aerofoil according to claim 2, wherein the detectable element is magnetic.

5. A method of manufacturing a hollow aerofoil according to claim 2, wherein the step of locating the capping panel comprises detecting the or each detectable element so as to accurately position the capping panel relative to the temporary mandrel.

6. A method of manufacturing a hollow aerofoil according to claim 2, further comprising:

machining an outer surface of the hollow aerofoil after the step of joining but before the step of removing the temporary mandrel, wherein

the machining step is based at least on part on the position of the or each detectable element.

7. A method of manufacturing a hollow aerofoil according to claim 1, wherein the joining step comprises diffusion bonding the first region of the inner surface of the capping panel to the surrounding hollowed surface of the pocketed aerofoil body.

8. A method of manufacturing a hollow aerofoil according to claim 7, further comprising:

locating one or both of the capping panel and the pocketed aerofoil body in a respective fixture prior to the diffusion bonding step; and

applying pressure to the respective fixture or fixtures so as to perform the diffusion bonding.

9. A method of manufacturing a hollow aerofoil according to claim 8, further comprising heating the or each respective fixture so as to perform the diffusion bonding.

10. A method of manufacturing a hollow aerofoil according to claim 1, wherein:

the joining step comprises liquid interface diffusion bonding; and

the method further comprises providing an interface foil layer between the first region of the inner surface of the capping panel and the surrounding hollowed surface of the pocketed aerofoil body in order to facilitate the liquid interface diffusion bonding.

11. A method of manufacturing a hollow aerofoil according to claim 1, wherein the temporary mandrel is substantially incompressible throughout the joining step.

12. A method of manufacturing a hollow aerofoil according to claim 1, wherein:

the temporary mandrel comprises an impermeable cavity defined by a flexible material and containing gas; and

the method comprises locating the capping panel in a fixture and generating a pressure differential across the flexible material so that it urges the capping panel in a direction away from the pocket.

13. A method of manufacturing a hollow aerofoil according to claim 1, wherein the temporary mandrel is coated with a material comprising a rare earth element oxide so as to prevent interaction between the temporary mandrel material and the pocketed aerofoil body or capping panel.

14. A method of manufacturing a hollow aerofoil according to claim 1, wherein the temporary mandrel comprises ceramic and/or rammed graphite.

15. A method of manufacturing a hollow aerofoil according to claim 1, wherein the step of removing the temporary mandrel from the hollow aerofoil comprises ultrasonic shattering or leeching.

16. A method of manufacturing a hollowed aerofoil according to claim 1, further comprising machining the pocket into an aerofoil blank in order to produce the pocketed aerofoil body.

17. A method of manufacturing an aerofoil comprising:

manufacturing a hollow aerofoil according to the method of claim 1; and

filling the hollow aerofoil with a core material after the step of removing the temporary mandrel.

18. An aerofoil manufactured according to the method of claim 1.

19. A gas turbine engine comprising an aerofoil according to claim 18.