Method for manufacturing a part made of composite material using a thin-walled mold

A method for manufacturing a part made of composite material, said material comprising reinforcing fibers and a polymer matrix, the method comprising the following successive steps:

• installing into a matrix mounted on a press a closed thin-walled mold wherein reinforcing fibers have been arranged,
• closing the press,
• injecting in the molten state into the closed thin-walled mold a polymer or a reactive composition comprising at least one prepolymer, at least one monomer or their mixture,
• maintaining the closing of the press for all or part of the polymerization of the polymer matrix, when a reactive composition is used,
• opening the press,
• removing the thin-walled mold from the press, while maintaining a residual pressure between 0.7 and 10 bar, in said mold,
• cooling the mold under said residual pressure,
• wherein the cooling step consists in positioning the thin-walled mold in a cold forming machine regulated at a temperature less than or equal to the crystallization temperature of the polymer formed under a residual pressure between 0.7 and 10 bar.