Tooling for producing z-channels in ceramic fiber preforms

1 . A needle array suitable for perforating a fibrous preform, the needle array comprising:

a backplate; and

a plurality of needles individually removably attached to and extending away from the backplate, each of the plurality of needles comprising:

a plurality of ceramic filaments secured together as a bundle forming a body of each respective needle;

a metallic sheath surrounding a first end of the bundle abutting the backplate; and

a single shaped tip on a second end of the bundle, the second end being oppositely disposed from the first end;

wherein the single shaped tip is a sharpened point or a rounded point.

2 . The needle array of claim 1 , wherein each of the ceramic filaments is formed from one of silicon carbide, silicon nitride, and aluminum oxide.

3 . The needle array of claim 2 , wherein each of the ceramic filaments further comprises an interface coating of at least one of boron nitride, silicon carbide, silicon nitride, and pyrolytic carbon.

4 . The needle array of claim 2 , wherein the bundle of ceramic filaments is further encased in a reinforcing coating comprising of one of epoxy, a ceramic, a polymer-derived ceramic, and a silicon alloy.

5 . The needle array of claim 1 , wherein the metallic sheath is secured to the bundle of ceramic filaments with an adhesive material.

6 . The needle array of claim 1 , wherein a width of the metallic sheath is greater than a width of the bundle of ceramic filaments.

7 . The needle array of claim 1 , wherein the shaped tip comprises one of silicon carbide precursor and a polymer material.

8 . A method of forming a needle suitable for perforating a fibrous preform, the method comprising:

arranging a plurality of ceramic filaments in a length-wise manner and securing the plurality of ceramic filaments together as a bundle forming a body of each respective needle;

coating the bundle with a reinforcing material;

wrapping a metallic sheath around the bundle such that the bundle has a sheathed portion at a first end and an exposed portion at a second end;

securing the metallic sheath to the bundle using an adhesive material; and

forming a single shaped needle tip on the second end of the bundle;

wherein each of a plurality of the needles is configured to be removably attached to a backplate to form a needle array in which the plurality of needles extends away from the backplate;

wherein forming the single needle tip comprises placing a rounded bead on the second end; or

wherein forming the single needle tip comprises sharpening the second end to form a point.

9 . The method of claim 8 , wherein the rounded bead is formed from one of a silicon carbide precursor and a polymer material.

10 . The method of claim 8 , wherein the second end is sharpened using one of a grinding wheel and a jig.

11 . The method of claim 8 , wherein the reinforcing coating comprises one of epoxy, a ceramic, a polymer-derived ceramic, and a silicon alloy.

12 . The method of claim 8 and further comprising: after forming the needle, applying silicon carbide to the needle using chemical vapor infiltration.

13 . A method of forming a needle array suitable for perforating a fibrous preform, the method comprising:

forming a plurality of needles, wherein forming each of the plurality of needles comprises:

arranging a plurality of ceramic filaments in a length-wise manner and securing the plurality of ceramic filaments together as a bundle forming a body of each respective needle;

coating the bundle with a reinforcing material;

wrapping a metallic sheath around the bundle such that the bundle has a sheathed portion at a first end and an exposed portion at a second end;

securing the metallic sheath to the bundle using an adhesive material;

forming a single shaped needle tip on the second end of the bundle; and

attaching each of the plurality of needles to a backplate such that the plurality of needles extends away from the backplate;

wherein forming the single needle tip comprises placing a rounded bead on the second end, wherein the rounded bead is formed from one of a silicon carbide precursor and a polymer material; or

wherein forming the single needle tip comprises sharpening the second end using one of a grinding wheel and a jig to form a point.