The present invention relates to an automatic method for manufacturing a stator or rotor blade preform for a turbine engine, comprising at least the following successive steps: a) a step for the helical braiding of a plurality of interlocked tubular braids (1), called nested braids, said step being conducted on braiding machines (2) placed in a row in a braiding direction; b) a step for flattening the nested braids (1); c) a step for stitching the nested braids (1) together in a direction perpendicular to the braiding direction; d) a step for winding the nested braids (1) on a transport mandrel (3); e) a step for cutting the nested braids (1) unwound from the transport mandrel (3), said cut being performed in a direction perpendicular to the braiding direction.