Method and apparatus for the recovery and regeneration of metal powder in EBM applications
The present invention relates to a method and an associated apparatus ( 1 ) for the recovery and regeneration of metal powder in EBM (Electron Beam Melting) applications. The method is of the type which envisages a step for recovery of weakly sintered powders inside a cleaning chamber ( 2 ) incorporating at least one compressed-air nozzle with supply, where necessary, of powder for sandblasting three-dimensional objects obtained by means of EBM sintering of the metal powders; according to the invention it is envisaged supplying into the cleaning chamber ( 2 ) metal powders having a predetermined low oxygen content and there is also a powder recirculating system ( 3 ) comprising at least one first buffer tank ( 9 ) inside which the regenerated powders are deposited for renewed supply of the aforementioned chamber ( 2 ).
1. Method for the recovery and regeneration of metal powders in EBM (Electron Beam Melting) applications, comprising a step for recovery of weakly sintered powders inside a cleaning chamber including at least one compressed-air nozzle for supplying powder for sandblasting three-dimensional objects obtained by means of EBM sintering of said metal powders, comprising a path for recovery and regeneration of said powders, comprising at least a first buffer tank inside which the regenerated powders are deposited and wherein metal powders with a predetermined oxygen content of less than 0.12% by weight are supplied at an access point along said path for recovery and regeneration, wherein the regenerated powders have an oxygen content that lies within a range of values of between 0.12% and 0.16% by weight, and wherein said cleaning chamber is formed with walls made of the same metallic material as the metal powders from which said three-dimensional objects are made to reduce powder contamination from the cleaning chamber.
2. The method according to claim 1 , wherein the supply of said metal powders with the predetermined oxygen content is performed directly inside said cleaning chamber.
3. The method according to claim 1 , wherein said cleaning chamber is kept under an overpressure of inert gas and that the jet emitted by the sandblasting nozzle is formed with the same type of compressed inert gas.
4. The method according to claim 1 , wherein a second buffer tank is connected downstream of and supplied by the first buffer tank for topping up one or more hoppers or tanks of corresponding EBM sintering apparatus.
5. The method according to claim 4 , wherein the regenerated powders of said second buffer tank undergo certification of the percentage oxygen content in said range of values between 0.12% and 0.16% by weight.
6. The method according to claim 1 , wherein said walls are made of titanium or alloys thereof, cobalt-chrome or magnesium and alloys thereof depending on the powders used to produce the three-dimensional objects obtained by means of EBM.
7. The method according to claim 6 , wherein the entire sandblasting portion of said cleaning chamber is made with metals corresponding to the powders of the objects produced, including said at least one nozzle and an associated flexible pipe.