Multi-mandrel braiding process
A system for forming multiple braided preform segments includes a mandrel assembly disposed along a mandrel axis, a radial braider for winding fibers onto the mandrel assembly to form a continuous braided article, an applicator for applying a polymer binder to the braided article while mounted on the mandrel assembly, and a debulking tool for debulking the braided article while mounted on the mandrel assembly. The mandrel assembly includes a lead-in extension defining a first end, an end extension defining a second end, and a plurality of mandrels removably connected to a plurality of transition pieces and disposed axially between the lead-in extension and the end extension.
1 . A system for forming multiple braided preform segments, the system comprising:
a mandrel assembly disposed along a mandrel axis, the mandrel assembly comprising:
a lead-in extension defining a first terminal end;
an end extension defining a second terminal end; and
a plurality of mandrels removably connected to a plurality of transition pieces and disposed axially between the lead-in extension and the end extension, wherein:
each of the plurality of mandrels extends and tapers between two axial ends; and
each of the transition pieces abuts and separates two of the plurality of mandrels and has a lateral dimension transverse to the mandrel axis, shared by abutting axial ends of both of the abutting two of the plurality of mandrels, and uniform throughout an entire axial extend of the respective transition piece between the abutting two mandrels;
a radial braider for winding fibers onto the mandrel assembly to form a continuous braided article; and
an applicator for applying a polymer binder to the braided article while mounted on the mandrel assembly.
2 . The system of claim 1 , wherein:
a first mandrel of the plurality of mandrels is removably connected to the lead-in extension;
a first transition piece of the plurality of transition pieces is removably connected to the first mandrel opposite the lead-in extension; and
a second mandrel of the plurality of mandrels is removably connected to the first transition piece opposite the first mandrel;
wherein the axially uniform dimension of the first transition piece is a first axially uniform dimension.
3 . The system of claim 2 , wherein:
the first mandrel is disposed such that it tapers from the lead-in extension to the first transition piece; and
the second mandrel is disposed such that it widens from the first transition piece toward the end extension.
4 . The system of claim 3 , wherein the lead-in extension has a second axially uniform dimension greater than the first axially uniform dimension of the first transition piece.
5 . The system of claim 4 , wherein the first mandrel tapers from the second axially uniform dimension to the first axially uniform dimension shared with the first transition piece, and wherein the second mandrel widens from the first axially uniform dimension shared with the first transition piece to the second axially uniform dimension.
6 . The system of claim 4 , wherein each of a first subset of the plurality of transition pieces has the first axially uniform dimension, and wherein each of a second subset of the plurality of transition pieces has the second axially uniform dimension.
7 . The system of claim 2 , wherein:
the first mandrel is disposed such that it widens from the lead-in extension to the first transition piece; and
the second mandrel is disposed such that it tapers from the first transition piece toward the end extension.
8 . The system of claim 1 , wherein the plurality of mandrels are formed from at least one of graphite, a metallic material, and plastic.
9 . The system of claim 1 , wherein the plurality of transition pieces are formed from at least one of graphite, a metallic material, and plastic.
10 . The system of claim 1 , wherein the plurality of mandrels comprises five mandrels.
11 . The system of claim 1 and further comprising: a robotic arm for translating and rotating the mandrel assembly.
12 . The system of claim 1 and further comprising: a cutting device for cutting the braided article into a plurality of preform segments.
13 . The system of claim 1 and further comprising: an optical device for inspecting the braided article.
14 . The system of claim 1 , wherein each of the plurality of mandrels comprises a plurality of pins or a plurality of slots and each of the plurality of transition portions comprises the other of the plurality of pins and the plurality of slots, the plurality of slots and the plurality of pins configured to mate to connect the plurality of mandrels to the plurality of transition portions.
15 . A method of forming multiple CMC parts from a braided article, the method comprising:
assembling a mandrel assembly, the mandrel assembly comprising:
a lead-in extension;
an end extension; and
a plurality of mandrels removably connected to a plurality of transition pieces and disposed axially between the lead-in extension and the end extension, wherein:
each of the plurality of mandrels extends and tapers between two axial ends; and
each of the transition pieces abuts and separates two of the plurality of mandrels and has a lateral dimension transverse to the mandrel axis, shared by abutting axial ends of both of the abutting two of the plurality of mandrels, and uniform throughout an entire axial extend of the respective transition piece between the abutting two mandrels;
incorporating the mandrel assembly into a braiding system;
forming a continuous braided article over the plurality of mandrels and the plurality of transition pieces;
cutting the braided article into a plurality of preform segments;
forming a corresponding plurality of preforms from the plurality of preform segments; and
densifying the plurality of preforms with a ceramic matrix.
16 . The method of claim 15 , wherein assembling the mandrel assembly comprises:
removably connecting a first mandrel of the plurality of mandrels to the lead-in extension;
removably connecting a first transition piece of the plurality of transition pieces to the first mandrel opposite the lead-in extension; and
removably connecting a second mandrel of the plurality of mandrels to the first transition piece opposite the first mandrel.
17 . The method of claim 16 , wherein assembling the mandrel assembly further comprises:
disposing the first mandrel such that it tapers from the lead-in extension to the first transition piece;
disposing the second mandrel such that it widens from the first transition piece toward the end extension; or,
disposing the first mandrel such that it widens from the lead-in extension to the first transition piece; and
disposing the second mandrel such that it tapers from the first transition piece toward the end extension.
18 . The method of claim 15 , wherein cutting the braided article comprises cutting along an axial midpoint of each of the plurality of transition pieces.
19 . The method of claim 18 , wherein the plurality of preform segments comprises five preform segments.
20 . The method of claim 15 , wherein the plurality of preforms are densified using chemical vapor infiltration.