Investment Casting Pattern Manufacture

• US 20080060781A1
• Filed: 07/31/2007
• Published: 03/13/2008
• Est. Priority Date: 09/01/2005
• Status: Active Grant

• Current Assignee: Rtx Corporation
• Original Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Santeler, Keith
• Granted Patent: US 7,438,118 B2
• Time in Patent Office: Days
• US Class Current: 164/235
• CPC Class Codes: B22C 21/14 for reinforcing or securing moulding materials or cores, e.g. gaggers, chaplets, pins, bars
• CPC Class Codes: B22C 7/02 Lost patterns
• CPC Class Codes: B22C 9/04 Use of lost patterns
• CPC Class Codes: B22C 9/064 Locating means for cores
• CPC Class Codes: B22C 9/103 Multipart cores

Abstract

At least one feedcore and at least one wall cooling core are assembled with a number of elements of a die for forming a cooled turbine engine element investment casting pattern. A sacrificial material is molded in the die. The sacrificial material is removed from the die. The removing includes extracting a first of the die elements from a compartment in a second of the die elements before disengaging the second die element from the sacrificial material. The first element includes a compartment receiving an outlet end portion of a first of the wall cooling cores in the assembly and disengages therefrom in the extraction.

Claims

1. A casting core comprising:

a main body for forming a cooling circuit within a wall of a turbine airfoil and having first and second spanwise ends, an inlet end, and an outlet end and curved to conform to an adjacent surface of the wall; and

a plurality of tabs extending from the outlet end and including at least two parallel tabs.

2. The core of claim 1 being a refractory metal core.

3. The core of claim 1 wherein:

the at least two parallel tabs include at least two tabs from each of at least two rows of tabs.

4. The core of claim 3 wherein:

the two rows include a first row and a second row, the second row spaced apart from the first row;

all tabs of the first row are parallel to each other; and

all tabs of the second row are parallel to each other.

5. The core of claim 1 wherein:

the at least two parallel tabs are of a first group of parallel tabs, parallel to each other; and

the plurality of tabs includes a second group of tabs parallel to each other.

6. The core of claim 1 wherein:

the at least two parallel tabs include all tabs from at least a first row of tabs.

7. The core of claim 1 wherein:

the at least two parallel tabs include at least two tabs bent back relative to the body and separated therefrom by less than 80°

.

8. A casting core assembly comprising:

a first casting core according to claim 1;

and

a ceramic feedcore, the inlet end being coupled to the ceramic feedcore.

9. The core assembly of claim 8 further comprising:

a second casting core according to claim 1, the inlet end thereof engaged to the ceramic feedcore and the at least two parallel tabs thereof extending off-parallel to the at least two parallel tabs of the first casting core.

10. A casting pattern comprising:

the core assembly of claim 9;

and

a pattern material molded over the core assembly.

11. The pattern of claim 10 wherein:

the pattern material forms an airfoil having a leading edge, a trailing edge, a pressure side, and a suction side.

12. The pattern of claim 11 wherein:

the first casting core is along the suction side; and

the second casting core is along the pressure side.

13. The pattern of claim 11 wherein:

the first casting core is along the suction side; and

the second casting core is along the suction side.

14. The pattern of claim 13 further comprising:

a third casting core according to claim 1 along the pressure side; and

a fourth casting core according to claim 1 along the pressure side.

15. The pattern of claim 11 wherein:

the at least two parallel tabs are oriented to form outlet slots inclined 15-60°

off normal to an adjacent surface.