Method for immobilising a preform in a mould
A method for manufacturing a turbine-engine blade from a preform made from polymerized composite material in a mold comprising a bottom part and a top part, comprising at least one closure step during which the top part of said mold is attached to the bottom part of the mold containing the preform, wherein it comprises, prior to said closure step, at least one insertion substep during which a first end of an immobilization element is inserted in a bottom part of the preform in a substantially transverse direction, and a positioning substep during which a second, opposite end of said element is disposed in a complementary reception cavity emerging in the bottom part of the mold.
1. A method for manufacturing a turbine-engine blade made from composite material, the method comprising:
producing a preform of general axial orientation, by weaving threads in three dimensions, said preform comprising a blade root part and a blade vane part;
placing the preform in a bottom part of a mold, a recess of which is substantially complementary to bottom parts of the blade root part and of the blade vane part of the preform;
closing the mold by attaching a top part of said mold, a recess of which is complementary to top parts of the blade root part and of the blade vane part of the preform, on the bottom part of the mold containing the preform;
compacting the preform in said mold: and
injecting a resin into the mold under vacuum in order to impregnate the compacted preform and to form a rigid blade after polymerization of the resin,
wherein, prior to said closing the mold, the method further comprises
inserting a first end of an immobilization element in a bottom part of the preform in a substantially transverse direction; and
positioning a second, opposite end of said element in a complementary reception cavity that opens into the recess of the bottom part of the mold.
2. The method according to claim 1 , further comprising, after said injecting a resin, eliminating the second end of said element.
3. The method according to claim 1 , wherein said inserting a first end of an immobilization element in a bottom part of the preform occurs prior to placing the preform in a bottom part of a mold, and wherein said positioning a second, opposite end of said element in a complementary reception cavity occurs during the second step.
4. The method according to claim 1 , wherein said positioning a second, opposite end of said element in a complementary reception cavity occurs during said placing the preform in a bottom part of a mold, and wherein said inserting a first end of an immobilization element in a bottom part of the preform occurs during said placing the preform in a bottom part of a mold and subsequent to said positioning a second, opposite end of said element in a complementary reception cavity.
5. The method according to claim 2 , wherein:
during said inserting a first end of an immobilization element in a bottom part of the preform, the immobilization element is inserted in a zone of the bottom part of the blade root intended to form part of a subsequently eliminated trimming;
the method further comprising
removing the polymerized rough preform from the mold and then cutting in order to separate trimmings from it, in order to obtain the final blade, wherein said eliminating the second end of said element being performed concomitantly with said cutting.
6. Impregnation mold for manufacturing a turbine-engine blade made from composite material, comprising a bottom mold part, a recess of which is substantially complementary to a bottom part of a blade preform, and a top part, a recess of which is substantially complementary to a top part of the blade preform, said top part being able to be attached to said bottom part, wherein the bottom part comprises at least one cavity that opens into the recess, which is configured to be complementary to an immobilization element secured to the blade preform, and which is able to provide reception thereof.
7. Impregnation mold according to claim 6 , wherein the cavity opens into a part of the recess in the bottom part of the mold that does not delimit a functional surface of the final blade.
8. Impregnation mold according to claim 6 , wherein said cavity has a shape complementary to a pin.