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 configured to receive a gas, - at least one first upstream powder conduit 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 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, between a rest position, in which the first upstream powder conduit 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 is fluidly connected to the downstream work conduit by the distributor, the upstream powder conduit being different from the upstream gas conduit, in that the distributor defines: - a first inner channel configured to place the first upstream powder conduit in fluid continuity with the downstream work conduit in the first supply position, and - a second inner channel configured to place the first upstream powder conduit 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 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 is fluidly connected by the first inner channel of the distributor to the downstream work conduit. - at least one first upstream gas conduit configured to receive a gas, - at least one first upstream powder conduit 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 configured in order to supply a nozzle designed for depositing at least the first powder (Pa), the upstream powder conduit being different from the upstream gas conduit, in that the distributor defines: - a first inner channel configured to place the first upstream powder conduit in fluid continuity with the downstream work conduit in the first supply position, and - a second inner channel configured to place the first upstream powder conduit 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 in fluid continuity with the downstream work conduit in the first supply position, and - a second inner channel configured to place the first upstream powder conduit 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 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 is fluidly connected by the first inner channel of the distributor to the downstream work conduit. - in the supply position, the first upstream gas conduit 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 is fluidly connected by the first inner channel of the distributor to the downstream work conduit.