Method for making parts in composite material with thermoplastic matrix

Fabrication process for parts from a composite material comprising a skin and stiffeners, the process comprising:

• separately fabricating stiffeners by lay-up, consolidation and shaping, starting from a strip of long fibers impregnated with thermoplastic resin;
• placing the stiffeners on a tooling with a shape complementary to the shape of the part to be fabricated;
• simultaneously fabricating and assembling the skin with the stiffeners by lay-up and continuous consolidation of strips of long fibers impregnated with thermoplastic resin, directly on the tooling on which the stiffeners are placed;
• and
• cooling a strip that has just been deposited to a temperature below the melting temperature of the thermoplastic resin, prior to adding an additional strip heated at a temperature above the melting temperature of the thermoplastic resin to weld the strips together by diffusion.