| 摘要 |
PROBLEM TO BE SOLVED: To shorten a heating and a cooling times and eliminate a bent shape keeping jig and the like by a method wherein a working flexible vinyl chloride resin tube, in which a bent-shaped metal core rod is inserted, is heated through the irradiation of far infrared rays and then cooled. SOLUTION: A flexible vinyl chloride resin tube 1 is inserted onto a metal core rod 4, the shape of which conforms to the desired shape, so as to be formed into a desired shape. Next, the resultant tube is charged in a far infrared furnace so as to be heated through the irradiation of far infrared rays. As its heating temperature, any temperature, under which f flexible vinyl chloride resin softens or melts, or higher will do. Next, the tube with the core rod as inserted is taken out of the furnace and then cooled. After the cooling of the tube is confirmed, the core rod 4 is removed. As a cooling method, either a cooling with water or a cooling with air will do. In this method, the flexible vinyl chloride resin tube 1 portion absorbs far infrared rays, resulting in being heated. While the core rod portion reflects far infrared rays, resulting in not being heated. As a result, the resin tube 1 portion can be heated efficiently and also cooled in a short period of time. |
