Method of manufacturing a component

Patent metadata

Field	Value
Publication number	US-12186797-B2
Application number	US-202418667726-A
Country	US
Kind code	B2
Filing date	May 17, 2024
Priority date	Jun 5, 2023
Publication date	Jan 7, 2025
Grant date	Jan 7, 2025

Abstract

A method of manufacturing a component includes forming a mould assembly including an initial mould unit, providing a seed crystal including a primary growth direction, determining an optimal angular orientation of the unit, rotating the unit to dispose the unit's optimal angular orientation, encasing the unit in a refractory material, and forming a refractory mould unit having a component mould including a mould wall defining a mould cavity, and a seed holder. In the optimal angular orientation, the seed crystal's primary growth direction is angled away from the wall, thereby forming a converging disposition with the wall in a of the wall's first region facing the central sprue and a diverging disposition with the wall in the wall's second region facing a mould heater. The method includes receiving the seed crystal within the seed holder and filling the mould cavity with molten castable material to form the component.

First claim

We claim:

1. A method of manufacturing a component, the method comprising the steps of:
forming a mould assembly comprising a central sprue extending along a central axis and an initial mould unit comprising a wax pattern and a seed section connected to the wax pattern, the wax pattern being made of a wax material and the seed section being made of a plastic material, the initial mould unit extending along a unit axis parallel to the central axis, wherein the initial mould unit is rotatable about the unit axis with respect to the central sprue;
providing a seed crystal comprising a primary growth direction;
determining an optimal angular orientation of the initial mould unit about the central axis relative to the central sprue if the primary growth direction of the seed crystal is disposed at a predetermined orientation with respect to the initial mould unit;
rotating the initial mould unit about the unit axis, such that the initial mould unit is disposed in the optimal angular orientation relative to the central sprue;
encasing the initial mould unit in a refractory material after disposing the initial mould unit in the optimal angular orientation relative to the central sprue;
removing the wax material and the plastic material to form a refractory mould unit extending along the unit axis, the refractory mould unit comprising a component mould corresponding to the wax pattern and a seed holder corresponding to the seed section, the component mould comprising a mould wall defining a mould cavity that is disposed in fluid communication with the seed holder and the central sprue, wherein each of the component mould and the seed holder is made of the refractory material, wherein the refractory mould unit is disposed in the optimal angular orientation relative to the central sprue, and wherein, in the optimal angular orientation of the refractory mould unit, the primary growth direction of the seed crystal is angled away from the mould wall, thereby forming a converging disposition with the mould wall in a first region of the mould wall facing the central sprue and a diverging disposition with the mould wall in a second region of the mould wall facing a mould heater;
receiving the seed crystal within the seed holder, such that the primary growth direction of the seed crystal forms the converging disposition with the mould wall in the first region of the mould wall and the diverging disposition with the mould wall in the second region of the mould wall; and
filling, via the central sprue, the mould cavity with molten castable material to form the component as a single crystal structure.

2. The method of claim 1 , wherein determining the optimal angular orientation of the initial mould unit comprises the steps of:
a) determining, using a thermal model, curvatures of a plurality of liquidus isotherms of the molten castable material as a function of time along the unit axis for a given angular orientation of the initial mould unit with respect to the central sprue;
b) determining, using the thermal model, a disposition of the primary growth direction of the seed crystal for the given angular orientation if a normal to at least one liquidus isotherm from the plurality of liquidus isotherms is inclined to the unit axis by an angle greater than 15 degrees and if the at least one liquidus isotherm slopes upwards towards an upper end of the component mould; and
c) repeating steps a) and b) by varying the given angular orientation till the optimal angular orientation is obtained.

3. The method of claim 1 , further comprising:
determining that the primary growth direction of the seed crystal is independent of an orientation of the initial mould unit;
removing the wax material and the plastic material to form the refractory mould unit extending along the unit axis without rotating the initial mould unit to the optimal angular orientation relative to the central sprue; and
receiving the seed crystal within the seed holder, such that the primary growth direction of the seed crystal is from 0 degree to 4 degrees with respect to the unit axis.

4. The method of claim 1 , further comprising positioning the initial mould unit on a carousel comprising the central sprue prior to rotating the initial mould unit about the unit axis.

5. The method of claim 1 , wherein the refractory material is a ceramic slurry.

6. The method of claim 1 , wherein the wax pattern and the seed section are formed as a single integral component.

7. The method of claim 1 , wherein the component is a blade of a gas turbine engine.

Assignees

• Rolls Royce Plc

Inventors

• D'Souza Neil
• Goodwin Kevin
• Lehane John D
• Perry Martin R

Classifications

• B22D27/20

  Measures not previously mentioned for influencing the grain structure or texture; Selection of compositions therefor · CPC title

• B22D25/06

  by its physical properties (B22D27/00 takes precedence) · CPC title

• B22C7/02 Primary

  Lost patterns · CPC title

• B22D27/045

  Directionally solidified castings · CPC title

• B22C9/24

  for hollow articles · CPC title