An
extrusion screw and a manufacturing method thereof, the
extrusion screw comprises a screw body and screw flights, the screw flights comprise a feeding section, a melting section, a transition section and a discharging section, the melting section is a double screw flight, the melting section comprises a melting first section, a melting second section and a melting third section, the
pitch of the main screw flight of the melting first section is smaller than the
pitch of the auxiliary screw flight of the melting first section, the
pitch of the main screw flight of the melting second section is equal to the pitch of the auxiliary screw flight of the melting second section, the pitch of the main screw flight of the melting third section is smaller than the pitch of the auxiliary screw flight of the melting third section, wherein the pitch of the main screw flight of the melting section remains unchanged, the pitch of the auxiliary screw flight of the melting third section is greater than the pitch of the auxiliary screw flight of the melting first section, and the pitch of the auxiliary screw flight of the melting first section is greater than the pitch of the auxiliary screw flight of the melting second section, the manufacturing method comprises manufacturing a rod-shaped structure, manufacturing the transition section, manufacturing the screw flights of the feeding section, the main screw flight and the auxiliary screw flight, and manufacturing the screw flights of the discharging section, and the advantages of the present application are that the material is sufficiently melted and mixed, and the extruded material is dense and smooth.