| 摘要 |
PURPOSE: To easily and inexpensively produce even a bent pipe bent in three- dimensional directions without generating thickness irregularity or burr in a molding process. CONSTITUTION: A raw pipe 1 composed of a flexible vinyl chloride resin is preheated and softened to be fitted to the outer periphery of a mandrel 2 composed of a stainless steel rod having a shape bent in three-dimensional directions X, Y, Z and heated at predetermined molding temp. for a predetermined time by hot steam and subsequently cooled by a cooling water shower to mold a bent pipe 1' which is, in turn, released by introducing compressed air into the gap between the bent pipe 1' and the mandrel 2. |
