A switching system for a facility for 3D printing by spraying at least a first powder (Pa), the switching system comprising a body defining: - at least one first upstream gas conduit (G1) configured to receive a gas, - at least one first upstream powder conduit (A) configured to receive the first powder (Pa), - at least one first downstream discharge conduit (Ra) for discharging the first powder (Pa), and - a downstream work conduit (T) configured in order to supply a nozzle designed for depositing at least the first powder (Pa), characterized in that it further comprises a distributor that is movable with respect to the body in rotation about an axis (D), between a rest position, in which the first upstream powder conduit (A) is fluidly connected to the first downstream discharge conduit (Ra) by the distributor , and at least a first supply position, in which the first upstream powder conduit (A) is fluidly connected to the downstream work conduit (T) by the distributor , the upstream powder conduit (A) being different from the upstream gas conduit (G1), in that the distributor defines: - a first inner channel configured to place the first upstream powder conduit (A) in fluid continuity with the downstream work conduit (T) in the first supply position, and - a second inner channel configured to place the first upstream powder conduit (A) in fluid continuity with the first downstream discharge conduit (Ra) in the rest position, and in that : - in the supply position, the first upstream gas conduit (G1) is connected by the distributor to the first downstream discharge conduit (Ra), by a third inner channel defined by the distributor , and - in the rest position, the first upstream gas conduit (G1) is fluidly connected by the first inner channel of the distributor to the downstream work conduit (T). - at least one first upstream gas conduit (G1) configured to receive a gas, - at least one first upstream powder conduit (A) configured to receive the first powder (Pa), - at least one first downstream discharge conduit (Ra) for discharging the first powder (Pa), and - a downstream work conduit (T) configured in order to supply a nozzle designed for depositing at least the first powder (Pa), the upstream powder conduit (A) being different from the upstream gas conduit (G1), in that the distributor defines: - a first inner channel configured to place the first upstream powder conduit (A) in fluid continuity with the downstream work conduit (T) in the first supply position, and - a second inner channel configured to place the first upstream powder conduit (A) in fluid continuity with the first downstream discharge conduit (Ra) in the rest position, - a first inner channel configured to place the first upstream powder conduit (A) in fluid continuity with the downstream work conduit (T) in the first supply position, and - a second inner channel configured to place the first upstream powder conduit (A) in fluid continuity with the first downstream discharge conduit (Ra) in the rest position, and in that : - in the supply position, the first upstream gas conduit (G1) is connected by the distributor to the first downstream discharge conduit (Ra), by a third inner channel defined by the distributor , and - in the rest position, the first upstream gas conduit (G1) is fluidly connected by the first inner channel of the distributor to the downstream work conduit (T). - in the supply position, the first upstream gas conduit (G1) is connected by the distributor to the first downstream discharge conduit (Ra), by a third inner channel defined by the distributor , and - in the rest position, the first upstream gas conduit (G1) is fluidly connected by the first inner channel of the distributor to the downstream work conduit (T). <EOS>