Method for the preparation of composite material in sandwich form

A method of manufacturing a sandwich-shaped composite material product wherein the sandwich-shaped composite material product comprises two outer layers and a core, the outer layers having a matrix of fiber-reinforced polymeric material, the polymeric material having a melting point below the melting point of the material constituting the fibers;

• wherein the method is characterized in that it uses an insert consisting of material having a melting point higher than the melting point of the polymeric material, on which the outer layers are consolidated;
• wherein this insert is subsequently replaced by the core of the sandwich-shaped composite material product to form an assembly, the assembly then undergoing a consolidation treatment for bonding the outer layers to the core;
• and
• wherein the method is further characterized in that it comprises the following steps:
• production of preforms composed of the fiber-reinforced polymeric material intended to become the outer lavers of the sandwich-shaped composite material product,
• juxtaposition, in a mold, of a first preform of the preforms, of the insert, and of a second preform of the preforms,
• consolidation of the preforms to obtain the outer layers, by heating and pressurizing, to reach the temperature of the melting point of the polymeric material, without reaching the temperature of the melting point of the reinforcing material or the material of the insert,
• removal of the insert, separation of the outer layers and insertion of the core of the sandwich-shaped composite material product,
• heat treatment to adhere the outer layers to the core,
• cooling of the product thus obtained.