EP-4737025-A1 - METHOD AND APPARATUS FOR SIMULTANEOUS HOT FORMATION OF HOLLOW COMPONENTS

EP4737025A1EP 4737025 A1EP4737025 A1EP 4737025A1EP-4737025-A1

Abstract

A method of hot forming a pair of hollow components. The method involves heating a die stack comprising a first die, an intermediate die and a second die, in which the first die and the intermediate die form a first die set, and the intermediate die and the second die form a second die set. The die stack is opened to create a first space between the first die and the intermediate die of the first die set, and a second space between the intermediate die and the second die of the second die set and loading a first component preform into the first space and a second component preform into the second space. Once loaded, the die stack is closed to hold the first component preform in the first die set, and the second component preform in the second die set. A pressurised fluid from a first finite reservoir is then provided via a first conduit to an internal cavity of the first component preform, while a pressurised fluid from a second finite reservoir is also provided via a second conduit to an internal cavity of the second component preform. Provision of the pressurised fluid to the internal cavities of the preforms deforming the first component preform and the second component preform and causes pressure within the cavities to drop as the cavities expand. Once determined that both a first pressure in the internal cavity of the first component preform and a second pressure in the internal cavity of the second component preform have fallen below a first threshold, the internal cavity of the first component preform and the internal cavity of the second component preform are both re-pressurised based at least in part on a common pressure: time schedule, to form the first component and second component of the pair of components. The die stack is opened and the first component and the second component removed from the respective first space and the second space.

Inventors

KELLY, DAVID J
Parameswaran, Elangovan
Storr, John V
BUCCONI, MARCO
Knowles, Craig E
Elrakayby, Hosam A
GONZALEZ, DIEGO

Assignees

Rolls-Royce plc

Dates

Publication Date: 20260506
Application Date: 20250930

Claims (15)

A method (100) of hot forming a pair of hollow components, the method comprising: heating (110) a die stack (200) comprising a first die (210), an intermediate die (220) and a second die (230), wherein the first die (210) and the intermediate die (220) form a first die set, and the intermediate die (220) and the second die (230) form a second die set; opening (120) the die stack (200), creating a first space (215) between the first die (210) and the intermediate die (220) of the first die set, and a second space (225) between the intermediate die (220) and the second die (230) of the second die set; loading (130) a first component preform (300) into the first space (215) and a second component preform (300) into the second space (225); closing (140) the die stack to hold the first component preform (300) in the first die set, and the second component preform (300) in the second die set; providing (150) a pressurised fluid from a first finite reservoir via a first conduit to an internal cavity (300c) of the first component preform (300), and a pressurised fluid from a second finite reservoir via a second conduit to an internal cavity (300c) of the second component preform (300), thereby deforming the first component preform (300) and the second component preform (300); determining (160) that both a first pressure in the internal cavity of the first component preform and a second pressure in the internal cavity of the second component preform have fallen below a first threshold; re-pressurising (170) the internal cavity (300c) of the first component preform (300) and the internal cavity (300c) of the second component preform (300) based at least in part on a common pressure: time schedule, thereby respectively forming the first component and second component of the pair of components; opening (180) the die stack (200); and removing (190) the first component from the first space (215) and the second component from the second space (225).
The method (100) of claim 1, wherein the first component preform (300) and the second component preform (300) are heated in the die stack (200) to a conditioning temperature for a conditioning period before their respective internal cavities (300c) are provided with the pressurised fluid.
The method (100) of claim 2, wherein the conditioning period has a variable duration.
The method (100) of claim 3, wherein completion of the conditioning period is determined by a temperature of both the first component preform and a temperature of the second component preform exceeding a temperature threshold.
The method (100) of any preceding claim, wherein the internal cavity (300c) of the first component preform (300) and the internal cavity (300c) of the second preform (300) component are purged of air prior to loading into the first space and second space respectively.
The method (100) of any preceding claim, wherein an orientation of the first component preform (300) in the first die set is equal to the orientation of the second component preform (300).
The method (100) of any preceding claim, wherein formation of the first component preform and formation of the second component preform comprises a diffusion bonding process.
The method (100) of any preceding claim, wherein the pressurised fluid is an inert gas.
The method (100) of any preceding claim, wherein re-pressurisation of the first component preform (300) is controlled independently from re-pressurisation of the second component preform (300).
The method (100) of any one of claims 1 to 8, wherein re-pressurisation of one of the first component preform (300) and the second component preform (300) is controlled based upon re-pressurisation of the other of the first component preform (300) and the second component preform (300).
The method (100) of any preceding claim, wherein the hot forming process is a super-plastic forming process.
The method (100) of any preceding claim, wherein the component is a gas turbine engine fan blade.
A hot forming machine for hollow components, the hot forming machine comprising: a first platen (240); a second platen (250); an actuation mechanism for a die stack (200) in which the die stack has a first die set which comprises a first die and an intermediate die, and a second die set which comprises the intermediate die and a second die, and the die stack is holdable between the first platen and the second platen; a heat source for heating the first die set and the second die set; and a pressurisation device comprising a first conduit connectable to a first component preform held in the first die set, a second conduit connectable to a second component preform held in the second die set, and at least one pressure sensor for sensing an internal cavity pressure of the first component preform and an internal cavity pressure of the second component preform; wherein the pressurisation device is switchable between a pressurisation mode and a re-pressurisation mode; and: in the pressurisation mode, the pressurisation device couples the first component preform to a first finite pressure reservoir and the second component preform to a second finite pressure reservoir; in the re-pressurisation mode, the first component preform and the second component preform are re-pressurised based upon a common pressure: time schedule; and switching from the pressurisation mode to the re-pressurisation mode occurs in dependence upon the sensed pressure in the first hollow component and sensed pressure in the second hollow component both falling below a first threshold.
The hot forming machine of claim 13, further comprising at least one temperature sensor, and the pressurisation device additionally comprising an isolation mode, wherein the pressurisation device is switchable from the isolation mode to the pressurisation mode in dependence upon both a sensed temperature of the first hollow component preform and a sensed temperature of the second hollow component preform exceeding a temperature threshold.
The hot forming machine of claim 13 or 14, wherein the pressurisation device further comprises a third conduit and a fourth conduit, wherein the third conduit is connectable to a third component preform and the fourth conduit is connectable to a fourth component preform.

Description

FIELD This disclosure relates to a method and apparatus for the simultaneous formation of hollow components. In particular it relates to a method and apparatus for the simultaneous formation of hollow metallic aerofoils such as hollow metallic fan blades for a gas turbine engine. BACKGROUND Hollow components, such as gas turbine engine fan blades, may be formed by a hot forming process, such as superplastic forming (SPF). Aerofoils are formed individually, in which a single hot forming press is used to form a single blade at any one time. Hot forming processes such as superplastic forming are energy intensive, whilst significant capital expenditure may be required to purchase or upgrade the hot-forming equipment. Manufacture of a hot-formed aerofoil is therefore both time consuming and energy intensive. Improvements in hot forming to reduce either the energy consumption or unit cost per manufactured aerofoil are therefore desirable. SUMMARY According to a first aspect, a method of hot forming a pair of hollow components is provided. The method comprises heating a die stack comprising a first die, an intermediate die and a second die, in which the first die and the intermediate die form a first die set, and the intermediate die and the second die form a second die set. The method additionally comprises opening the die stack to create a first space between the first die and the intermediate die of the first die set, and a second space between the intermediate die and the second die of the second die set and loading a first component preform into the first space and a second component preform into the second space. Once loaded, the die stack is closed to hold the first component preform in the first die set, and the second component preform in the second die set. A pressurised fluid from a first finite reservoir is then provided via a first conduit to an internal cavity of the first component preform, while a pressurised fluid from a second finite reservoir is also provided via a second conduit to an internal cavity of the second component preform. Provision of the pressurised fluid to the internal cavities of the preforms deforms the first component preform and the second component preform and causes pressure within the cavities to drop as the cavities expand. Once it is determined that both a first pressure in the internal cavity of the first component preform and a second pressure in the internal cavity of the second component preform have fallen below a first threshold; the internal cavity of the first component preform and the internal cavity of the second component preform are both re-pressurised based at least in part on a common pressure: time schedule, to form the first component and second component of the pair of components. The die stack is opened, and the first component and the second component removed from the respective first space and the second space. The first component preform and the second component preform may be heated in the die stack to a conditioning temperature for a conditioning period before their respective internal cavities are provided with the pressurised fluid. The internal cavity of the first component preform and the internal cavity of the second preform component may be flushed with an inert gas prior to loading into the first space and second space respectively. The conditioning period may have a variable duration. If the conditioning period has a variable duration, completion of the conditioning period may be determined by a temperature of both the first component preform and a temperature of the second component preform may exceed a temperature threshold. An orientation of the first component preform in the first die set may be equal to the orientation of the second component preform. This may reduce mechanical loading on the dies of the die stack, and in particular, on the intermediate die between the first die and the second die. Formation of the first component preform and formation of the second component preform may comprise a diffusion bonding process. The pressurised fluid may be an inert gas, for example, argon. In some embodiments, re-pressurisation of the first component preform may be controlled independently from re- pressurisation of the second component preform. Alternatively, re-pressurisation of one of the first component preform and the second component preform may be controlled based upon re-pressurisation of the other of the first component preform and the second component preform. The hot forming process may be a super-plastic forming process. The pair of components formed by the hot forming process may be a pair of gas turbine engine fan blade, for example, a pair of hollow metallic gas turbine engine fan blades. According to a second aspect a hot forming machine for hollow components is also provided. The hot forming machine comprises a first platen, a second platen and an actuation mechanism for a die stack in which the die stack has a first die s