Method for creating cooling holes in a CMC laminate

1. A method for forming a hole in a ceramic matrix composite component, the method comprising:

providing a first tool component with a first hole, wherein the first hole is stepped hole having a first hole portion with a first diameter and a second hole portion with a second diameter less than the first diameter;

providing a fiber preform of the ceramic matrix composite component on the first tool component;

positioning a second tool component on the fiber preform, such that the fiber preform is disposed between the first and second tool components, wherein the second tool component has a second hole coaxial with the first hole, the second hole having a third diameter larger than the second diameter;

inserting a guide tube into the first and second holes and through the fiber preform, wherein the guide tube has an outer diameter greater than the diameter of the second hole portion of the first hole and wherein the guide tube has an angled end having a non-90 degree angle;

inserting a rod into the first and second holes and through the fiber preform; and

performing a densification step of the fiber preform in the first and second tool components, wherein the fiber preform is densified with a ceramic matrix.

2. The method of claim 1 , wherein the first hole portion and second hole portion are coaxial.

3. The method of claim 1 , wherein inserting the guide tube into the first hole comprises inserting the guide tube into the first hole portion.

4. The method of claim 3 , wherein inserting the rod into the first hole comprises inserting the rod through the first hole portion and into the second hole portion.

5. The method of claim 4 , and further comprising removing the guide tube from the first and second tool components.

6. The method of claim 5 , and further comprising densifying the fiber preform in the first and second tool components with the rod extending into the first and second holes and through the fiber preform.

7. The method of claim 6 , and further comprising removing the rod from the densified fiber preform.

8. The method of claim 1 , wherein the fiber preform comprises braided or woven fibers.

9. A tool for forming holes in a ceramic matrix composite component, the tool comprising:

a first tool component having a first hole wherein the first hole is stepped hole having a first hole portion with a first diameter and a second hole portion with a second diameter less than the first diameter; and

a second tool component configured to confine a fiber preform of ceramic matrix composite component between the first and second tool components, the second tool component having:

a second hole extending through the second tool component and having a third diameter, wherein the second hole is coaxial with the first hole and wherein the third diameter is larger than the second diameter; and

a plurality of third holes to allow passage of densifying gases to the fiber preform, the third holes having a larger diameter than the second hole; and

a guide tube configured to be received in the first and second holes, wherein the guide tube has an outer diameter greater than the diameter of the second hole portion of the first hole and wherein the guide tube has an angled end having a non-90 degree angle.

10. The tool of claim 9 , wherein the first hole portion opens to a surface positioned to be adjacent to the fiber preform.

11. The tool of claim 9 , wherein the guide tube is configured to extend through the second hole and into the first hole portion of the first hole.

12. The tool of claim 9 , and further comprising a sacrificial rod configured to be received in the guide tube.

13. The tool of claim 12 , wherein the sacrificial rod is configured to extend through the second hole and first hole portion of the first hole and into the second hole portion of the first hole.

14. The tool of claim 10 , wherein the second hole opens to a first surface and an opposite second surface of the second tool component, the first surface positioned to be adjacent to the fiber preform.