| 摘要 |
A tube with a thin thickness or a thin tube made of a synthetic resin material having high heat-resistance and high strength (for example, PEI material, PEEK material or the like) is produced by means of extrusion molding. An extrusion molding method forms a continuous product (5) for a thin tube by plasticizing and kneading a raw material (1) composed of a synthetic resin material having high heat-resistance and high strength by means of an extrusion molding machine (2), extruding the plasticized and kneaded raw material from a molding die (3) to form a tubular body (51) having a circular cross section, further passing the tubular body (51) on a sizing die (4) to give a final inner diameter to the tubular body (51), cooling and hardening the tubular body (51). The molding die (3) and sizing die (4) are coupled to each other by a connecting pipe (6). The sizing die (4) is made of a carbon material. A first air (81) is supplied to an interior of the sizing die (4) through the connecting pipe (6). A second air (92) is supplied to an interior of the molding die (3) so that an air lubrication layer is formed between an inner surface (52) of the continuous product (5) and an outer surface (41) of the sizing die (4). The first air (81) is exhausted as a third air (84) through the connecting pipe (6) out of the extrusion molding machine (2) after the first air (81) cools the sizing die (4). The second air (92) passes through a space defined between the inner surface (52) of the continuous product (5) and the outer surface (41) of the sizing die (4) and leaves the continuous product (5).
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