Disclosed is a switching system for a facility for 3D printing by spraying at least a first powder, including 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; at least one first downstream discharge conduit for discharging the first powder; and a downstream work conduit configured in order to supply a nozzle designed for depositing at least the first powder. The system further includes a distributor that is movable with respect to the body, preferably in rotation about an axis, between a rest position, in which the first upstream powder conduit is fluidly connected, via the distributor, to the first downstream discharge conduit, and at least a first supply position, in which the first upstream powder conduit is fluidly connected, via the distributor, to the downstream work conduit.