Abstract: A pressure releasing material feeding screw rod used in a melting metal material injection machine is disclosed. A plurality of adjacent threads are arranged along a longitudinal direction of the screw rod. The threads include a plurality of normal pressure threads and a plurality of pressure reduction threads which are alternatively arranged. An edge of each pressure reduction threads have a gap with the wall of the material feeding cylinder, or the pressure reduction threads is made of flexible plate. When the normal pressure threads push the melting material forwards, as the melting material in the material feeding cylinder generates an overlarge reacting force on a surface of the normal pressure thread, the gap will receive the material or the flexible pressure reduction threads will form a gap so that melting material can pass through this gap. Then the material will be pushed by next normal pressure thread.

Abstract: A pressure releasing material feeding screw rod used in a melting metal material injection machine is disclosed. A plurality of adjacent threads are arranged along a longitudinal direction of the screw rod. The threads include a plurality of normal pressure threads and a plurality of pressure reduction threads which are alternatively arranged. An edge of each pressure reduction threads have a gap with the wall of the material feeding cylinder, or the pressure reduction threads is made of flexible plate. When the normal pressure threads push the melting material forwards, as the melting material in the material feeding cylinder generates an overlarge reacting force on a surface of the normal pressure thread, the gap will receive the material or the flexible pressure reduction threads will form a gap so that melting material can pass through this gap. Then the material will be pushed by next normal pressure thread.