Apparatus for additive manufacturing includes:—a platform adapted to receive a powder bed that is laid thereon; —a laser source adapted to emit a laser beam towards the powder bed; —a first doctor blade and a second doctor blade opposite to the first doctor blade and located at a predetermined distance from said first doctor blade, the doctor blades being adapted to move in the same direction (X), so as to slide along the whole platform and define a work area, into which the laser beam is directed in order to manufacture a product; wherein the powder bed (102) is laid out by the first doctor blade, and the first doctor blade is provided with an emission opening adapted to produce a blade of a predetermined gas directed towards the powder bed, and the second doctor blade is provided with a suction opening for sucking in the gas when the product is complete, the suction opening being provided with a sensor adapted to measure the turbulence of the gas flow in the work area, so as to maintain, through a control unit, a laminar flow between the emission opening and the suction opening.