Vacuum negative-pressure self-casting device for melting crucibles

The invention discloses a vacuum negative-pressure self-casting device for melting crucibles. A melting crucible is arranged on a fixing flange through a crucible base; the bottom of the melting crucible is provided with a red copper screw; a central through hole of the red copper screw is communicated to the bottom of the melting crucible; a negative-pressure cavity is arranged on the fixing flange at the lower end of the red copper screw; a lower-end opening of the negative-pressure cavity is connected with a molding die; a gap is reserved between an upper-end opening of the molding die and the lower end of the red copper screw; a molding die jacket is provided with a negative-pressure suction tube; and the negative-pressure suction tube is communicated with the negative-pressure cavity through a plurality of through holes on the fixing flange. The device fundamentally overcomes the deficiencies of the prior casting technique, allows the negative-pressure cavity and the melting crucible to be balanced in pr