The invention relates to a device and a method for molding and consolidation of a textile preform. The invention belongs to the field of consolidation / curing a preform of a fibrous plies laminating prepregs of a thermosetting or thermoplastic polymer.
According to the prior art, the plies constituting the preform are draped manually or by means of a lay-up machine on a matrix reproduces the shape of the part to be obtained. ply layup techniques preimpregnated with a thermosetting or thermoplastic polymer are known from the prior art and are not discussed further. After draping, stratification obtained and the matrix are bagged sealed by a tarpaulin. The interior of said tank, comprising the textile preform is drawn by vacuum and placed either in an oven or autoclave, to bring the whole preform, and bagging matrix at a temperature of consolidation or pressure cooking.

Both the autoclave which are frequently oven unique means of production in a production plant and constitute throttle in the workflow, especially in the field of thermosetting matrix composites whose resin has a finite open time for the achievement cooking. In addition, the temperature rise of the assembly consisting of the tooling and the preform to the firing temperature / consolidation is long in such means.

Also, many independent tools, including their own heating means have been developed. Said devices comprise integrated heating means in the form of electrical resistors, ducts of oil circulation, or inducers. However, integration of the heating means in the tooling is expensive in terms of machining.

The WO2015 / 155369 discloses a cooking device / consolidation of a textile preform, with independent heating and interchangeable matrix. This prior art device is particularly suitable for the realization of a large piece but is complex in its design to incorporate

heating and cooling means as regards the parts with smaller dimensions, the surface is less than or equal to about 1 m 2 .

The invention aims to solve the drawbacks of the prior art and relates for that purpose a device for cooking / consolidation of a textile preform pre-impregnated with a polymer comprising:

at. a matrix free from heating and cooling means, comprising a molding face reproducing the shape of the textile preform and a mounting interface;

b. a sealed bagging of the preform on the die;

c. vacuum draw means inside the bagging comprising the fabric preform;

d. a thermal block, comprising induction heating means and a receiving interface cooperating with the die mounting interface for positioning and transferring heat between said matrix and said thermal block.

Thus, the heating means are not carried by the matrix which remains simple to produce. The mounting interface allows use of the same thermal block for a plurality of tools.

The invention is advantageously implemented according to the embodiments and variants described below, which are to be considered individually or in any technically operative combination.

Advantageously, the thermal unit comprises cooling means According to one embodiment particularly suitable for cooking a textile preform preimpregnated with a thermosetting resin, the object of the invention comprises:

e. a sealed chamber and means for locking said housing to the matrix;

f. means for mounting the pressure inside the sealed enclosure Advantageously, the thermal block of the object of the invention comprises:

di. a carrier comprising the receiving interface and a heating interface;

dii. a heat accumulator is heated by the induction heating means;

diii. means pourcommuniquer the chaleurde the accumulateurthermique the support by heating the interface.

This embodiment can limit the need for electrical power for powering the heating of the thermal block means while enjoying the benefits of induction heating.

Advantageously, the cooling means comprise a circuit for circulating a heat transfer fluid in the holder.

Advantageously, the cooling means comprise a circuit for circulating a heat transfer fluid around the heat accumulator.

Advantageously, the heater interface comprises a shaping sheet. Whereby said sheet conformation ensures perfect mechanical contact at the interface of heating and reduces the contact thermal resistance between the heat accumulator and the holder.

Similarly, the matrix comprises a mounting interface conformation sheet.

The invention also relates to a method for cooking or the consolidation of a prepreg textile preform of a polymer, embodying the device of the invention in any of its embodiments, which process comprises the steps consists in :

i. bagging the previously wrapped preform on the die;

ii. to evacuate the inside of the bagging:

iii. transfer the matrix and the preform bagged on the thermal block; iv. subjecting the preform thermal cycling cooking consolidation by controlling the temperature of the preform by heating and cooling the thermal block

According to an embodiment suitable for cooking a textile preform impregnated with a thermosetting polymer, the object of the invention method comprises, between steps ii) and iv) a step of increasing the pressure in the chamber watertight

The invention is explained below according to its preferred embodiments,

no way limiting, and with reference to Figure 1, showing sectional views according to the object of the invention device in an embodiment comprising all of the optional features thereof. Figure 1A in the cooling phase and 1B in the heating phase.

According to this exemplary embodiment, the object the invention device comprises a matrix (1 10) on which is draped textile preform (100) consisting of a prepreg laminating fibrous plies of a thermosetting polymer or thermopastique. Said preform (100) is bagged on the die (110) through a vacuum tank (120), implementing a sealing means (121) so that the space between the die (1 10) and the vacuum cover, comprising the preform (100) is sealed. According to this exemplary embodiment, the matrix (110) comprises ducts (11 1) opening into said space, which ducts are connected to a suction pump (not shown) so as to draw the vacuum space. A sealed enclosure (130) ensérant the preform is locked to the matrix by assembly means (132) suitable. Said enclosure comprises a conduit (132) connected to a pump to increase the pressure in said enclosure. Thus, the upper assembly comprising the die (110) means and bagging the sealed enclosure is a self-contained assembly, allowing the implementation of the pressure cycle corresponding to the consolidation / curing the textile preform.

The embodiment of the thermal cycle of consolidation / curing the textile preform is obtained by setting the upper assembly on a thermal block, wherein the thermal unit comprises, according to this embodiment:

- a support (140) made of a material having good thermal conductivity, for example, an aluminum alloy;

- a base (150) preferably made of a refractory material transparent to the magnetic field, for example, a concrete or a céramiquee;

- an accumulator (160) thermal made of a material heatable by induction.

The base includes an induction circuit comprising one or more inductors (151) circulating in cavities formed in said base and connected to a high-frequency current generator, typically between 10 kHz and 100 kHz.

The support (140) comprises channels (141) for circulating a coolant for cooling said support. The array is connected to the support (140) via a standard interface profile, so that a plurality of upper assemblies corresponding to a same shape or different shapes is likely to take position on the boc thermal. The mounting surface of the matrix surface which ensures the positioning of said matrix on the receiving surface of the support (140) advantageously comprises a shaping sheet (1 12). Said sheet conformation is, for example brazed to the joining surface of the matrix and consists of a material having good thermal conductivity but malleable, such as copper or nickel, so that said conforming sheet compensates for slight differences in shape between the joining surface of the matrix and the medium receiving surface (140).

On the face opposite the receiving face, the holder includes a heating surface which may come in contact with the heat accumulator. Advantageously, the heating surface comprises a shaping sheet (142) soldered to said heating surface, and adapted to compensate the light gaps formed between said accumulator (160) and the heating surface of the support (140). Figure 1 A, in the absence of heating, the accumulator (160) is not in contact with the heating surface. However, said accumulator (160) is nevertheless maintained at a known temperature maintenance via the inductors. The contact resistance between the accumulator (160) and the heating surface is high and the heat transfer between the heat accumulator (160) and the support (140) is reduced.

1B, during heating, the temperature of the battery is increased, so that it thermally expands and comes into contact with the heating surface of the support (140). The contact resistance lower, and the heat accumulator transmits its heat to the support. Said heat accumulator (160) has no structural function in the device object of the invention. Its incorporation are thus chosen to optimize its response to induction heating and its ability to transfer its heat to the support (140).

According to a particular embodiment, detail Z, said accumulator is of cellular structure, each cell (165) being filled with a phase change material having a latent heat of transition. Advantageously, the phase change material is selected such that its transition temperature is close to the holding temperature of the heat accumulator. For example, if the holding temperature is in the range of 200 ° C the phase change material is for example an organic material such as a polyol. If the holding temperature is higher, for example of the order of 400 ° C or more, the phase change material is for example a salt. According to these examples, the phase change material changes from the solid state at low temperature, the higher temperature liquid state by absorbing a latent heat of transition. Passing the high temperature phase to the low temperature phase of the phase change material solidifies and restores said latent heat of transition. The combination of the honeycomb structure and the presence of a phase change material increases the apparent thermal inertia of the heat accumulator (160) for maintaining it at the holding temperature, any retaining ability rapid heating to the heating temperature.

Cooling the matrix, and as a result of the preform is achieved by the circulation of the coolant in the channels (141) of the support. Advantageously, the base (150) comprises channels (152) for the supply of a heat transfer fluid around the heat accumulator (160) so as to accelerate its cooling to its holding temperature after the heating phase and retention temperature of the matrix.

CLAIMS
Apparatus for cooking / consolidation of a textile preform pre-impregnated with a polymer characterized in that it comprises: a. a matrix free from heating and cooling means, comprising a molding face reproducing the shape of the textile preform and a mounting interface; b. A sealed bagging of the preform on the die;

c. Means for drawing vacuum within the bagging comprising the fabric preform;

d. a thermal block, comprising induction heating means and a receiving interface cooperating with the die mounting interface for positioning and transferring heat between said matrix and said thermal block

Device according to claim 1, wherein the thermal block comprises cooling means.

Device according to claim 1 comprising:

e. a sealed chamber and means for locking said housing to the matrix;

f. means for mounting the pressure within the sealed enclosure.

Device according to any one of claims 1 to 3, wherein the thermal block comprises:

di. a carrier comprising the receiving interface and a heating interface;

dii. a heat accumulator is heated by the induction heating means;

diii. means for communicating heat from the heat accumulator to the support by heating the interface.

Device according to claim 4, wherein the cooling means comprise a circuit for circulation of a coolant in the holder.

Device according to claim 5, wherein the cooling means comprise a circuit for circulation of a heat transfer fluid around the heat accumulator.

Device according to claim 4, wherein the interface comprises a heating sheet conformation.

Device according to any one of claims 1 to 7, wherein the matrix comprises a mounting interface conformation sheet.

A method for cooking or the consolidation of a textile preform pre-impregnated with a polymer, using a device according to any one of the preceding claims, characterized in that it comprises the steps of:

i. bagging the previously wrapped preform on the die; ii. to evacuate the inside of the bagging:

iii. transfer the matrix and the preform bagged on the thermal block;

iv. subjecting the preform thermal cycling cooking consolidation by controlling the temperature of the preform by heating and cooling the thermal block.

The method of claim 9, using a device according to claim 3, comprising, between steps ii) and iv) a step of increasing the pressure in the sealed enclosure.