A fluid transfer device including a rotor having two centrifugal wheels, and a stator incorporating a set of continuous axi symmetric return channels conveying the fluid from the first wheel to the second wheel. Each of the return channels includes in succession a diffusing portion that guides the fluid in a centrifugal direction, a bend portion that redirects the fluid stream in a centripetal direction, a return portion that guides the fluid along a centripetal path, and then an outlet portion formed in a first non-tubular part that guides the fluid towards the second wheel. In these channels, the diffusing portion and the bend portion are distinct parts, and the diffusing portion is formed in a second non-tubular part secured to the first non-tubular part. A method of fabricating the device.

An electrical discharge machining apparatus comprises a carrier and an electrical discharge machining (EDM) unit. The carrier is provided with a jig comprising a carrier plate for carrying a to-be-machined object, and the to-be-machined object is defined with a machining target area. The electrical discharge machining (EDM) unit applies a discharge energy to the machining target area through a discharge electrode with a non-uniform electric field distribution, so that the electric field is concentrated on a traveling direction. The carrier plate has an adhesive layer capable of adhering and fixing the to-be-machined object, capable of avoiding jitter of the to-be-machined object during an electrical discharge machining procedure, and capable of avoiding burrs before an end of the electrical discharge machining procedure, and making the machining target area to be located above the carrier plate to be capable of preventing the jig from hindering the electrical discharge machining procedure.