Method of making airfoils

Patent metadata

Field	Value
Publication number	US-11014151-B2
Application number	US-201916705003-A
Country	US
Kind code	B2
Filing date	Dec 5, 2019
Priority date	Mar 29, 2017
Publication date	May 25, 2021
Grant date	May 25, 2021

Abstract

A method of making an airfoil includes making a refractory metal core that defines an interior of the airfoil by a tomo-lithographic process, making a mold that defines an exterior of the airfoil, inserting the refractory metal core into the mold, and pouring an airfoil material between the refractory metal core and the mold to cast the airfoil.

First claim

The invention claimed is:

1. A method of making an airfoil, the method comprising:
making a refractory metal core that defines an interior of the airfoil by a tomo-lithographic process, wherein the tomo-lithographic process comprises:
forming a first layer of the refractory metal core out of a first material;
forming a second layer of the refractory metal core out of the first material;
bonding the first and second layers together to form a laminate master pattern;
forming a flexible mold around the laminate master pattern;
removing the laminate master pattern from the flexible mold;
pouring a pulverulent refractory metal material mixed with a binder into the flexible mold; and
sintering the pulverulent refractory metal material in an oxygen-free environment to form the refractory metal core;

making a mold that defines an exterior of the airfoil;
inserting the refractory metal core into the mold; and
pouring an airfoil material between the refractory metal core and the mold to cast the airfoil.

2. The method of claim 1 , further comprising:
removing the airfoil from the mold; and
removing the core from the airfoil.

3. The method of claim 2 , wherein removing the core from the airfoil comprises applying an acid treatment.

4. The method of claim 1 , further comprising:
applying a ceramic coating to the refractory metal core prior to pouring the airfoil material.

5. The method of claim 4 , further comprising:
applying a metallic layer to the refractory metal core.

6. The method of claim 5 , wherein the metallic layer comprises platinum, another noble metal, chromium, and/or aluminum.

7. The method of claim 1 , wherein the refractory metal core comprises one of the following materials: molybdenum, tantalum, niobium, or tungsten.

8. The method of claim 1 , further comprising:
generating a computer model of the refractory metal core;
slicing the computer model into a plurality of digital layers; and
analyzing a plurality of empty spaces in an airfoil to generate the computer model of the refractory metal core.

9. The method of claim 1 , further comprising:
placing the refractory metal core into a wax injection die;
placing a ceramic core into the wax injection die;
encapsulating the refractory metal core and the ceramic core with a wax material to form a first wax pattern;
assembling a first wax pattern with a second wax pattern to form a wax assembly;
investing the wax assembly into a wet ceramic slurry mix;
investing the wax assembly into a dry ceramic stucco with intermittent controlled drying to build up a thickness of ceramic shell on the exterior of the assembly;
drying the thickness of ceramic shell; and
removing the wax material from the ceramic shell.

10. The method of claim 9 , further comprising:
firing the ceramic shell in an oxygen-free environment;
cleaning the ceramic shell;
casting a component in the ceramic shell;
removing the ceramic shell from the component;
removing the ceramic core with a caustic solution that is heated and under pressure; and
removing the refractory metal core with an acid solution.

Assignees

• United Technologies Corp

Inventors

• Marcin John Joseph
• Zelesky Mark F
• Wagner Joel H
• Hall Theodore W
• Krause David A
• Reinert Ben S

Classifications

• B22C7/00

  Patterns; Manufacture thereof so far as not provided for in other classes · CPC title

• B22C9/04

  Use of lost patterns · CPC title

• F04D29/582

  specially adapted for elastic fluid pumps · CPC title

• B23K2103/12

  Copper or alloys thereof · CPC title

• B22C9/103

  Multipart cores · CPC title