METHOD AND EQUIPMENT FOR PRODUCING A PART BY INJECTING RESIN INTO A WOVEN FIBRE PREFORM

Abstract

A method for producing a part by injecting resin into a woven fiber preform includes the steps of (a) shaping the preform, (b) forming the preform, and (c) injecting resin into the preform. The step of injecting resin into the preform is carried out by means of equipment that includes a mold, a countermold, and resin injecting means. The step of injecting resin into the preform includes the substeps of: partially opening the equipment, injecting resin into the equipment, closing the equipment, and pressurizing and heating the impregnated preform between the mold and the countermold.

Claims

1. A method for producing a part by injecting resin into a woven fiber preform, the method comprising the steps of: shaping the preform; forming the preform; and injecting resin into the preform by equipment comprising a mold, a countermold, and means for injecting resin, wherein injecting resin into the preform and molding comprises the substeps of: partially opening the equipment by moving one of the mold and the countermold away from the other of the mold and the countermold; injecting resin into the equipment; closing the equipment, by bringing one of the mold and the countermold closer to the other of the mold and the countermold; and pressurising and heating the impregnated preform between the mold and the countermold.

2. The method according to claim 1, wherein said steps of shaping the preform, forming the preform, and injecting resin into the preform are carried out by means of said equipment, said mold defining a cavity configured to implement the step of shaping the preform, and the equipment further comprising means for suctioning air and injecting resin.

3. The method according to claim 1, further comprising, before the step of shaping the preform, the steps of: producing the preform by weaving fibers; and sizing the preform.

4. The method according to one claim 1, wherein the step of shaping the preform comprises the substeps of humidifying the preform and positioning the preform in the cavity of the mold.

5. The method according to claim 1, wherein the step of forming the preform comprises the substeps of closing the equipment and heating and putting the preform under vacuum between the mold and the countermold.

6. The method according to claim 1, wherein the substep of partially opening the equipment is carried out by extending the countermold by a predetermined distance from the mold, the mold and the countermold remaining substantially interlocked with one another.

7. The method according to claim 1, wherein the resin is injected through a port of the equipment, and the vacuum is produced by suctioning air through another port of the equipment.

8. The method according to claim 1, wherein said steps are carried out by means of a single item of equipment.

9. Equipment for implementing the method according to claim 1, the equipment comprising: an upper heating plate and a lower heating plate, the lower heating plate being integral with a mold comprising a cavity for shaping a preform, the upper heating plate being integral with a countermold comprising another cavity, a motorized means for moving plates from an extended position to a position wherein the mold and the countermold are interlocked with one another, the motorized means being configured to apply a compression force to the upper and lower plates in view of pressurising the preform between the cavities.

10. The equipment according to claim 9, wherein the upper and lower plates form part of a press of which the lower plate forms a base and the upper plate is mounted sliding in a vertical direction on guiding columns.

11. The equipment according to claim 9 further comprising means for laser projection of the contours of the preform on the cavity of the mold.

Description

DESCRIPTION OF THE FIGURES

[0040] The invention will be best understood, and other details, features and advantages of the invention will appear upon reading the following description, given as a non-limiting example in reference to the appended drawings, in which:

[0041] FIG. 1a is a block diagram representing steps of a method according to the prior art for producing a part made of composite material,

[0042] FIG. 1b is a block diagram representing steps of a method according to the prior art for moulding a part by injecting resin into a woven fibre preform,

[0043] FIG. 2a is a block diagram representing steps of a method according to the invention for producing a part made of composite material,

[0044] FIG. 2b is a block diagram representing steps of a method according to the invention for moulding a part by injecting resin into a woven fibre preform,

[0045] FIG. 3 is a schematic view of an item of equipment for implementing the method of FIGS. 2a and 2b,

[0046] FIG. 4 is a schematic, perspective view of the mould and countermould of the equipment of FIG. 3, and

[0047] FIGS. 5 to 7 are other schematic views of the equipment of FIG. 3 and illustrate steps of the method.

DETAILED DESCRIPTION

[0048] FIGS. 1a and 1b have been described above, and represent a method according to the prior art.

[0049] FIGS. 2a and 2b illustrate a method according to the invention for producing a part made of composite material, these steps being preferably carried out by means of the equipment 100 represented in FIG. 3 and below.

[0050] The equipment 100 comprises, in the main, a mould 102 integral with a lower plate 104, preferably heating, and a countermould 106 integral with an upper plate 108, also preferably heating. Sealing means are preferably provided between the mould and the countermould. In the example represented, the lower plate 104 forms a base for supporting the equipment, which can, for example, rest on the floor of a production workshop.

[0051] The mould 102 is situated on an upper face of the plate 104 and comprise a cavity 110, which can best be seen in FIG. 4. In the example represented, the cavity 110 is that of a face of a fan blade, such as the upper side thereof, for example. The cavity 110 here is oriented upwards and faces a cavity 112 of the countermould, which can also best be seen in FIG. 4, the countermould 106 being situated above the mould and facing the latter. The cavity 112 here is that of another face of a fan blade, such as the lower side thereof, for example.

[0052] The plate 108 is slidably mounted on guiding columns 114, here two of them, which extend between the lower ends thereof connected to the plate 104 and the upper ends thereof connected to a mast 116. The plate 108 and the countermould 106 are moved in substantially vertical translation by means of an actuator 118 or similar, of which a cylinder is fixed to the mast 116 and of which a piston is connected to the plate 108.

[0053] The plate 108 and the countermould 106 are movable from an upper position, represented in FIG. 3, in which the equipment is open and the mould 102 and the countermould 106 are at a distance from one another, and an interlocked or closer together position in which the equipment is closed and the mould and the countermould are engaged in one another, represented in FIG. 3. Intermediate positions can be considered, such as the position of FIG. 6, in which the equipment is open and the mould and the countermould are partially disconnected from one another, the countermould being extended by a predetermined distance from the mould. The equipment 100 is also used to pressurise the preform 200 in the cavity defined by the cavities 110, 112, by a predetermined force applied by the actuator 118 on the plate 108 (arrow 120).

[0054] The equipment 100 further comprises means for heating the plates 104, 108, not shown, as well as means for putting under vacuum and supplying the cavity defined by the cavities 110, 112.

[0055] The evacuation means comprise a first port 122 localised, for example, in the mould and of which an end opens into the cavity 110. The other cavity of this port 122 is intended to be connected to suction means such as a pump, not shown.

[0056] The supply means comprise a second port 124 localised, for example, in the mould and of which an end opens into the cavity 110. The other end of this port 124 is intended to be connected to resin injection means, not shown.

[0057] The equipment can further comprise laser projection means 126, in particular, of the contours of the preform 200 on the cavity 110 of the mould, in order to facilitate the positioning thereof at the start of the method.

[0058] The different steps of an embodiment of the method according to the invention will now be described, from FIGS. 2a, 2b, 3, 5 and below.

[0059] A first step a) of the method consists of producing a preform 200 by three-dimensionally weaving, by means of a weaving loom, for example of the Jacquard type. Coming out of the weaving loom, the preform is raw and has a generally flat shape and is expanded.

[0060] A step b) according to the method consists of shaping the preform 200, for example, by cutting its floats.

[0061] Steps a) and b) are similar to steps 1) and 2) of the method of the prior art, described in the above.

[0062] Step c), as well as the following steps differ from steps 3) and below of the prior art, in that they are implemented by means of the equipment 100 represented in FIGS. 3 and 5 to 7.

[0063] FIG. 3 illustrates step c) which consists of shaping the preform 200. For this, the preform is preferably humidified beforehand to make it more malleable. It is placed in the cavity 110 of the mould 102 using laser projection means 126. These projection means make it possible, for example, to correctly position tracers which would be integrated to the preform 200 in predefined positions.

[0064] FIG. 5 illustrates step d) which consists of subjecting the preform to a forming. For this, the equipment is closed and pressurised, for example between 5 and 10 bars, then heated, for example, to 100 C., using heating plates 104, 108 and the actuator 118. A residual vacuum is applied in the cavity receiving the preform using suction means, which makes it possible to remove the humidity from it (arrow 128). During this step, the preform is compacted to the final desired geometry, and dried by heating. The preform 200 is thus ready for the injection.

[0065] FIGS. 6 and 7 illustrate step e) which consists of injecting the resin 202 into the cavity of the equipment 100. For this, the equipment is partially open (step e1), the countermould being extended from the mould by a predetermined distance, as explained in the above. This makes it possible for the supply of a resin volume, strictly necessary to wet the preform and fill the final geometry of the part (respecting the fibre ratio). During this resin injection operation (arrow 130step e2), the mould and the countermould are preferably heated, and the resin also.

[0066] The equipment is then closed (FIG. 7step e3) and a pressure of 3 to 10 bars, for example, is applied by the actuator to the preform 200. The temperature can be maintained at 150 C. during the injection and increased to 180 C. for the polymerisation of the resin. As represented in the drawing by means of arrows, the pressure is preferably maintained constant over the whole extent of the part during the polymerisation (step e4).

[0067] The resin used is, for example, an epoxy resin such as that known under reference CYCOM PR520, commercialised by the company CYTEC.

[0068] After polymerisation, the equipment 100 is opened, the part 200 is removed and the equipment can be cleaned for a new production operation.

[0069] The piston of the prior art, for injecting resin into the equipment, here is replaced by the upper countermould which applies a pressure and makes it possible for the impregnation of the preform with the resin. The resin thus remains under constant and permanent pressure during the polymerisation thereof, which makes it possible to avoid any porosity in the part.

[0070] The invention can provide several advantages. A correct quantity of resin can be used, which is economical. When pipes are used (for example, copper pipes) with the prior art, the assembly is disposed of after the injection, as the resin hardens inside. With the invention, the pipes can be removed, even significantly shortened. A part made of composite material is obtained with the expected dimensions (mould against mould) and with smooth (aerodynamic) surfaces. Fluid, such as water or oil, is not used for the pressurisation. Resins which are even more difficult to inject can be used, with increased viscosities. It is possible to have a pressure, which changes during the phase of maintaining the pressure (in particular, in the case of the resin PR520 which can be compressible or have its volume decrease when it polymerises).