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 process for moulding and curing of a fibrous material embedded in a matrix of a thermocurable resin comprising locating an insert within a mould cavity which comprises a top, a base and cavity side walls, said insert comprising sectional walls that can move independently of each other to change the shape of the insert, providing a layer of fibrous material embedded in a matrix of thermocurable resin between the insert and the cavity side walls, placing the top onto the cavity and enlarging the insert to compress the layer of fibrous material between the insert and the cavity side walls and heating to cure the thermocurable resin; wherein 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 20 to 40 degrees; wherein the fibrous material embedded in a matrix of thermocurable resin comprises a layer of randomly oriented segments of unidirectional tape impregnated with resin, said segments being arranging in a quasi-isotropic fashion; and wherein said quasi-isotropic segments of unidirectional tape are at least partially derived from recycled materials.

2. The process according to claim 1 in which the fibrous material is processed into a preform before introduction into the mould.

Description

(1) The invention is illustrated by reference to the accompany drawings in which

(2) FIG. 1 shows a rectangular mould according to this invention.

(3) FIG. 2 shows the side walls of the mould of FIG. 1.

(4) FIG. 3 shows the mould of FIG. 2 containing a fibrous material in a resin matrix being moulded according to the present invention.

(5) FIG. 4 shows a mould for producing thrust reverser elements by means of an embodiment of the process of the invention.

(6) 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.

(7) 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).

(8) 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.

(9) 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.

(10) 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.

(11) 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.

(12) 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.