IMPROVEMENTS IN OR RELATING TO MOULDING

Abstract

A mould for the production of articles comprising a cavity for the retention of a fibrous material impregnated with a curable resin defined by a top, a base (1) and side walls (4, 5, 6, 7) and an internal insert (2) having sectional walls that can move independently of each other in order to exert pressure on the fibrous material.

Claims

1. A mould for the production of articles comprising a cavity for the retention of a fibrous material impregnated with a curable resin defined by a top, a base and cavity sidewalls and an internal insert having sectional walls that can move independently of each other to increase and decrease the dimensions of the insert in order to exert pressure on the fibrous material.

2. A mould according to claim 1 in which at least two of the sectional walls are inclined to each other at an angle of from 1 to 90 degrees.

3. A mould according to claim 1 in which the sides of the sectional walls are tapered to provide a wedge shape so that the walls can be moved to compress and mould the fibrous material embedded in a matrix of thermocurable resin against the cavity side walls, top and base in a manner that provides a continuous peripheral moulding surface.

4. A mould according to claim 1 wherein the insert comprises an elastomeric surround or cover.

5. A mould according to claim 4, wherein the surround or cover is self releasing to thermocurable resin.

6. A mould according to claim 5, wherein the surround or cover acts as a barrier preventing ingress of resin into the internal insert.

7. A mould according to claim 1 wherein the sectional walls are movable by contact with a punch.

8. A mould according to claim 1 wherein the mould is further provided with means to cure the resin.

9. A process for the moulding and curing of fibrous material embedded in a matrix of a thermocurable resin comprising locating an insert within a mould cavity comprising a top, a base and cavity side walls, the insert comprising sectional walls that can move independently of each other to increase and decrease the dimensions of the insert, providing a layer of fibrous material embedded in a matrix of thermocurable resin between the insert and the outer walls of the cavity, placing the top onto the cavity and increasing the dimensions of the insert to compress the layer of fibrous material between the sectional side walls of the insert and the cavity walls and heating to cure the thermocurable resin while compressed between the walls of the cavity and the insert.

10. A process according to claim 9 in which at least two of the sectional walls of the insert are inclined to each other to engage with a punch at an angle of from 1 to 90 degrees.

11. A process according to claim 9 in which the fibrous material is provided as a layer around the insert in the mould.

12. A process according to claim 9 which the fibrous material is processed into a preform before introduction into the mould.

13. A process according to claim 12 wherein the insert is provided within the preform when the preform containing the insert is inserted into the cavity of a mould.

14. A process according to claim 9 in which the fibrous material embedded in a matrix of a thermocurable resin is a moulding compound, a prepreg or a semipreg.

15. A process according to claim 14 wherein the moulding compound comprises randomly oriented segments of unidirectional tape that are impregnated with resin.

16. A process according to claim 15 in which the moulding compound is a quasi-isotropic material composed of segments of unidirectional fibre tape and a resin matrix.

17. A process according to claim 16 in which the resin is selected from bismaleimde resins and thermosetting epoxy resins.

18. A process according to claim 16 in which the quasi-isotropic material is at least partially derived from prepreg, semipreg, towpreg, tape or mixtures thereof.

19. A process according to claim 16 in which the quasi-isotropic material is at least partly derived from recycled material.

20. (canceled)

21. Aerospace components or other composite components made by a process according to claim 9.

Description

[0054] The invention is illustrated by reference to the accompany drawings in which

[0055] FIG. 1 shows a rectangular mould according to this invention.

[0056] FIG. 2 shows the side walls of the mould of FIG. 1.

[0057] FIG. 3 shows the mould of FIG. 2 containing a fibrous material in a resin matrix being moulded according to the present invention.

[0058] FIG. 4 shows a mould for producing thrust reverser elements by means of an embodiment of the process of the invention.

[0059] FIG. 1 shows a part of a prototype mould comprising a base plate (1), an insert (2) and a central punch (3) provided in the base plate, the top plate is not shown. Also the expandable elastomeric surround or membrane or cover which envelopes the insert is not shown in the drawings. This surround conforms to the surface of the expandable insert to ensure a smooth surface and good release properties on the inside of the moulded article.

[0060] FIG. 2 shows the independently movable side walls (4), (5), (6) and (7) provided on the mould part shown in FIG. 1 and FIG. 3 shows the completed mould apart from the top plate containing the insert, the fibrous material in the matrix of curable section (8).

[0061] FIG. 3 shows how the system would have been if the top plate was present after insertion of the fibrous material and the insert. The top plate would have been locked at a certain distance from the base so that the moulding material was forced into the corners as the side walls moved to their moulding positions (9), (10), (11) and (12) as is shown in FIG. 3.

[0062] In use, a layer of fibrous material embedded in a matrix of thermocurable resin is located between the insert and the outer walls of the cavity, the top is placed onto the cavity and the sections of the insert walls are moved independently to compress the layer of fibrous material between each sectional side wall of the insert and the outer walls of the cavity and the insert and the assembly is heated to cure the thermocurable resin while compressed between the walls of the cavity and the insert.

[0063] The mould shown in FIGS. 1 to 3 includes top plate, top lid and a punch. The top plate and top lid are linked with a spring system. In sequence, the top lid shuts onto the movable side walls creating a locked compression chamber. The spring system maintains pressure onto the lid while the punch moves down until it reaches the insert side walls. The tapering of the side walls cause the insert side walls to move simultaneously inwards to apply pressure onto the fibrous material.

[0064] FIG. 4 shows the manufacture of multiple inserts which can be used in cascade thrust reversers. The light coloured part is an additional forming part which does not form part of the inserts.

[0065] Similar to the sequence as shown in FIG. 2, mold moving side walls (4, 5, 6 and 7) are moved in the final position and subsequently, the insert side wall is moved to their molding positions. This applies pressure to the surrounding material so that the stretchable membrane forms the interface between insert side walls and the material.