Method for manufacturing a composite part and preform for manufacturing same

A method for manufacturing a segmented discrete ply (8) intended for the formation of a discrete segmented multilayer mat, the method comprising:

• a) supplying a continuous single-layer sheet (1) comprising,
• a continuous pre-impregnated layer (3) composed of unidirectional fibers disposed parallel to a longitudinal direction (D), the fibers being embedded in a resin matrix,
• a continuous antiadhesive lining (2) applied to a face of the continuous pre-impregnated layer,
• b) cutting the continuous single-layer sheet (1) supplied in the step a) so as to form, in the continuous pre-impregnated layer (3), segments (4) disposed in staggered fashion and thus form a segmented continuous sheet (5), said cutting being performed in such a way as to leave the continuous antiadhesive lining (2) intact;
• c) cutting the segmented continuous sheet (5) obtained in the step b) transversely along two cutting lines (6, 7) parallel to cutting directions (d1, d2, d3), oriented obliquely with respect to the longitudinal direction (D), the segmented continuous sheet (5) being cut over its entire width and thickness, including the antiadhesive lining, thus forming a segmented discrete ply (8) formed by a discrete segmented pre-impregnated layer (3ds) and the antiadhesive lining, and wherein the cutting lines (6, 7) form a cutting angle (α) with the longitudinal direction (D);
• wherein, a continuous sheet is a sheet having a geometry inscribed within a rectangle of length (L) and of width (I) with length-to-width ratio (L/I) greater than 20 and a discrete ply is a ply having a geometry inscribed within a rectangle of length (L) and of width (I) of length-to-width ratio (L/I) less than or equal to 20.