| 摘要 |
PURPOSE:To provide a kerf easily on the inner side of a resin tube by means of a cutting edge equipped on the outer side of a diameter expanding core fixed to the core part of a circular die. CONSTITUTION:When a resin tube 5 extruded from a circular die 1 makes its way directed by an arrow A, its diameter is exanded by a core 3, the heat-shrinking resin tube is produced continuously by being drawn by a pair of drawing roll 6. Since the resin tube which is passing the expanded part (conical part) of the core 3 is kept over the softening point, under the pour point, the core 3 is made up so that the medium for regulating temperature can pass through the inner side of the core 3. The core 3 is provided with a cutting edge 7 and a kerf is given on the inside of the tube. If the cutting edge 7 is mounted near the circular die 1 at the conical part of the core 3 the kerf hits the tube which is not elongated, that is, the relatively thick place of the tube and it is easy to regulate the depth of the kerf. |
