Abstract: A method for preparing composite parts, including a step of depositing at least one band of fibrous material impregnated with a thermoplastic polymer on a substrate, by means of a main heating system selected from the following two systems: a preheating system (1) and a heating system (2), in combination with at least one secondary heating system selected from: a heating system (3), a post-heating system (4), a heating system (5), and a preheating system (6), or by means of the two main heating systems (1) and (2), the substrate being previously devoid of any deposited band or comprising at least one band n?1 of said fibrous material, the thermoplastic polymer being amorphous, with a Tg such that Tg?80° C., or semicrystalline, with a Tm?150° C.

Abstract: Impregnation of a fibrous material made from continuous fibres with a thermoplastic polymer matrix, the fibrous material comprising a thermoplastic sizing polymer and, before impregnation, an initial width. The method comprises an expansion step which is carried out by means of at least two tensioning members (E) and a heating system SC for heating the tensioning members and/or the fibrous material, the expansion being from 1.5 to 5 times the initial width. The expanded fibrous material is cooled below the Tg of the thermoplastic sizing polymer by means of a cooling system before being brought into contact with the thermoplastic polymer matrix.