CPC B29C 48/51 (2019.02) [B29B 7/426 (2013.01); B29B 7/429 (2013.01); B29B 7/483 (2013.01); B29B 7/484 (2013.01); B29B 7/487 (2013.01); B29B 7/489 (2013.01); B29B 7/7461 (2013.01); B29B 7/7485 (2013.01); B29B 7/845 (2013.01); B29C 48/67 (2019.02); B29B 7/82 (2013.01); B29C 48/03 (2019.02); B29C 48/2564 (2019.02); B29C 48/2565 (2019.02); B29C 48/385 (2019.02); B29C 48/402 (2019.02); B29C 48/54 (2019.02); B29C 48/55 (2019.02); B29C 48/57 (2019.02); B29C 48/725 (2019.02); B29C 48/763 (2019.02); B29C 48/767 (2019.02); B29C 48/83 (2019.02); B29K 2033/12 (2013.01); B29K 2069/00 (2013.01)] | 5 Claims |
1. An extrusion method of kneading a raw material with an extruder screw configured to convey the raw material while kneading the raw material and continuously producing and extruding the kneaded material, wherein the extruder screw comprises a screw main body having a straight axial line in a conveyance direction of the raw material and configured to rotate on the axial line, conveyance portions provided in an axial direction of the screw main body and configured to convey the raw material in the axial direction and in the conveyance direction along an outer circumferential surface extending in a circumferential direction of the screw main body with rotation of the screw main body, barrier portions provided on the screw main body and configured to limit conveyance of the raw material at positions adjacent to the conveyance portions, and paths provided inside the screw main body and each comprising an entrance and an exit, the extrusion method comprising:
conveying the raw material in the axial direction by the conveyance portions of the screw main body, wherein the entrance is opened in the outer circumferential surface of the screw main body in one of the conveyance portions to cause the raw material to flow in;
limiting the conveyance of the raw material by the barrier portions of the screw main body to increase the pressure on the raw material;
causing the raw material, the pressure on which is increased, to flow into the paths provided inside the screw main body and flow through the paths in the opposite direction to the conveyance direction of the conveyance portions; and
returning the raw material flowing through the paths to the outer circumferential surface of the screw main body via the exit at a position on an upstream side in the conveyance direction in one of the conveyance portions in which the entrance is opened, wherein the exit is opened in the outer circumferential surface of the screw main body at the position on the upstream side in the conveyance direction in the one of the conveyance portions in which the entrance is opened.
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