Method and device for the manufacture of a composite ring
A process for manufacturing a composite block of closed geometry, in the form of a continuous ring, based on reinforcing fibres and on a cross-linkable resin, by continuously winding in superposition a predetermined number Nc of layers of a tape of the reinforcing fibres embedded in a matrix based on a composition comprising the cross-linkable resin, the method comprising, from the upstream end downstream, the steps of: forming a tape made of the reinforcing fibres, the thickness of the tape being between 0.1 mm and 0.5 mm; depositing the tape on a support that dictates the final shape of the composite block, and winding the tape onto the support, in a single direction, by superposing the number Nc of layers in order directly to form the continuous ring on the support, Nc being less than 15.
1. A process for manufacturing a composite block of closed geometry, in the form of a continuous ring, based on reinforcing fibres and as a cross-linkable resin, by continuously winding in superposition a predetermined number Nc of layers of a tape of the reinforcing fibres embedded in a matrix based on a composition comprising the cross-linkable resin, the process comprising, from the upstream end downstream, the steps of:
producing a rectilinear arrangement of reinforcing fibres, and conveying this arrangement in a feed direction;
degassing the arrangement of fibres under the action of a vacuum;
after degassing, impregnating said arrangement of fibres with the resin composition in the liquid state;
passing the pre-preg thus obtained through a die to impose on said pre-preg the shape of a tape consisting of the reinforcing fibres in their liquid resin matrix, the thickness (denoted “Er”) of said tape being between 0.1 mm and 0.5 mm;
on leaving the die, applying a surface treatment to the upper face of said tape in order to create a solid skin the thickness (denoted “Ep”) of which represents less than 10% of the thickness Er of the tape, so that said skin acts as a base for the subsequent winding of the tape on itself; and
depositing the thus superficially treated tape on a support that dictates the final shape of the composite block, and winding said tape onto said support, in a single direction, by superposing the number Nc of layers in order directly to form the continuous ring on the support, Nc being less than 15.
2. The process according to claim 1 , wherein the reinforcing fibres are chosen from the group consisting of glass fibre, carbon fibre, and mixtures of such fibres.
3. The process according to claim 1 , wherein the resin of the composition is a resin that can be cross-linked by ionizing radiation.
4. The process according to claim 1 , the resin being a polyester resin or a vinyl ester resin.
5. The process according to claim 4 , the vinyl ester resin being an epoxy novolac vinyl ester resin and/or a bisphenol epoxy resin.
6. The process according to claim 1 , the skin thickness Ep representing less than 5% of the thickness Er of the tape.
7. The process according to claim 1 , the thickness Er of the tape being between 0.10 and 0.35 mm.
8. The process according to claim 1 , the thickness Ep of the skin being between 2 and 10 μm.
9. The process according to claim 1 , the surface treatment consisting in a treatment to cross-link the resin.
10. The process according to claim 9 , the cross-linking treatment consisting of an ionizing treatment.
11. The process according to claim 10 , the ionizing treatment consisting of a UV treatment.
12. The process according to claim 1 , Nc being less than 10.
13. The process according to claim 12 , Nc being between 5 and 10.
14. The process according to claim 1 , the thickness of said ring being between 0.5 and 5.0 mm.
15. The process according to claim 14 , the thickness of said ring being in a range from 1 to 2 mm.
16. The process according to claim 1 , the width of said ring being less than 25 mm.
17. The process according to claim 16 , the width of said ring being in a range from 5 to 20 mm.