System and method for producing structural thermoplastic parts
A system for producing at least one structural thermoplastic part, said structural thermoplastic part being formed from a rough part comprising reinforcing fibres immersed in a thermoplastic matrix, the structural thermoplastic part to be produced comprising an outer face and an inner face, opposite the outer face, the production system comprising at least one inflatable pressure member made of a material having a thermal resistance greater than the heating temperature, the inflatable pressure member being mounted between the first counter-mould and the second mould, the inflatable pressure member being configured to develop between the deflated idle state and an inflated state to flatten the rough part between the imprint of the first mould and the imprint of the first counter-mould so as to consolidate the rough part and to form the structural thermoplastic part.
1. A system for producing at least one structural thermoplastic part, intended to be integrated in a primary structure of an aeroplane, said structural thermoplastic part being formed from a rough part comprising reinforcing fibres immersed in a thermoplastic matrix, the structural thermoplastic part to be produced comprising an outer face and an inner face, opposite the outer face, the production system comprising:
a first mould, comprising an inner imprint intended to form the outer face of the thermoplastic part to be produced,
a first counter-mould comprising an outer imprint intended to form the inner face of the thermoplastic part to be produced, the rough part being intended to be mounted between the first mould and the first counter-mould,
a second mould configured to be mounted opposite the first mould,
a device for closing the moulds so as to prevent a gap between them,
a device for heating the rough part at a heating temperature greater than the melting temperature of the thermoplastic matrix, so as to make it malleable,
at least one inflatable pressure member made of a material having a thermal resistance greater than the heating temperature, the inflatable pressure member being mounted against the first counter-mould and the second mould,
the inflatable pressure member being configured to develop between a deflated idle state and an inflated stress state, wherein the inflatable pressure member is configured to flatten the rough part between the imprint of the first mould and the imprint of the first counter-mould so as to consolidate the rough part and to form the structural thermoplastic part.
2. The system according to claim 1 , wherein the imprint of the first mould has a length greater than 5 m.
3. The system according to claim 1 , wherein the inflatable pressure member is configured to resist a heating temperature at least equal to 350° C.
4. The system according to claim 1 , wherein the inflatable pressure member is configured to resist a heating temperature at least equal to 600° C.
5. The system according to claim 1 , wherein the inflatable pressure member is made of a polyimide or silicone type material.
6. The system according to claim 1 , wherein the inflatable pressure member is inflated at an inner pressure of between 1 bar (1000 hPa) and 15 bars (15000 hPa).
7. The system according to claim 1 , wherein the inflatable pressure member is inflated at an inner pressure of between 7 bars (7000 hPa) and 12 bars (12000 hPa).
8. The system according to claim 1 , wherein, the second mould comprising a second imprint, said production system comprising a second counter-mould mounted between the inflatable pressure member and the second mould, the inflatable pressure member is configured to, in the stressed state thereof, flatten both a first rough part between the first counter-mould and the first mould and a second rough part between said second counter-mould and the second mould so as to make it possible for the simultaneous production of two structural thermoplastic parts.
9. The system according to claim 1 , wherein the first counter-mould comprises a first part and a second part which are connected by means for adjusting the clearance.
10. The system according to claim 1 , wherein the first counter-mould comprises a first part and a second part which are connected by a flexible portion for adjusting the clearance.
11. The system according to claim 1 , wherein the inflatable pressure member comprises, in the idle state, at least one inner fold.
12. The system according to claim 1 , wherein the first counter-mould is made of a material having a thermal expansion coefficient which is similar to that of the rough part.
13. A production method by the production system according to claim 1 of a structural thermoplastic part from a rough part, the rough part being positioned between the imprint of the first mould and the imprint of the first counter-mould, the inflatable pressure member being in a deflated idle state, said method comprising:
a step of heating the thermoplastic matrix of the rough part so as to make it malleable, and
a step of inflating the inflatable pressure member in an inflated stressed state wherein the inflatable pressure member flattens the rough part between the imprint of the first mould and the imprint of the first counter-mould so as to consolidate the rough part and to form the structural thermoplastic part.