A method for manufacturing an aircraft or turbomachine part for an aircraft, by injection molding of at least a first green element and a second (3a, 3b) green element of the said part, the said part to be manufactured being a turbomachine compressor rectifier sector or a turbomachine turbine nozzle sector in which method: a) a mixture of a powder and a polymeric binder, which is liquid or molten, is prepared for each of the first and second elements, adapted to enable the powder grains to be bonded together, b) the prepared mixtures are injected into molds adapted to the shape of the first and second elements respectively, so as to obtain two green blanks of the first and second elements respectively, c) once the binder has become consistent, the two green blanks are removed from the respective molds, d) at least one assembly area (9a, 9b) of at least one of the two green blanks, which must be located at the interface (13, 13a) between the said two green blanks to be assembled together, is heated, so that molten binder is present at the location of the said assembly area, e) the two green blanks are assembled together through the said at least one assembly area, so as to obtain an overall green blank of the said part, f) at least part of the binder is removed from the overall green blank, so as to obtain a debonded overall green blank, and g) a sintering treatment is carried out on the debonded overall green blank, characterised in that the said two green blanks, respectively of the first element and the second element, are green blanks, respectively: - of at least one part of the rectifying vane of the said rectifier sector or nozzle sector, and - of a sector of an outer ring or a sector of an inner ring of the said rectifier sector or nozzle sector, with which one end of the said at least one part of the rectifying vane is to be assembled in step e). a) a mixture of a powder and a polymeric binder, which is liquid or molten, is prepared for each of the first and second elements, adapted to enable the powder grains to be bonded together, b) the prepared mixtures are injected into molds adapted to the shape of the first and second elements respectively, so as to obtain two green blanks of the first and second elements respectively, c) once the binder has become consistent, the two green blanks are removed from the respective molds, d) at least one assembly area (9a, 9b) of at least one of the two green blanks, which must be located at the interface (13, 13a) between the said two green blanks to be assembled together, is heated, so that molten binder is present at the location of the said assembly area, e) the two green blanks are assembled together through the said at least one assembly area, so as to obtain an overall green blank of the said part, f) at least part of the binder is removed from the overall green blank, so as to obtain a debonded overall green blank, and g) a sintering treatment is carried out on the debonded overall green blank, - of at least one part of the rectifying vane of the said rectifier sector or nozzle sector, and - of a sector of an outer ring or a sector of an inner ring of the said rectifier sector or nozzle sector, with which one end of the said at least one part of the rectifying vane is to be assembled in step e).