| 摘要 |
PURPOSE:To provide projected pins at the tip of a core bar extruding port in a crosshead part, and further mechanically forming clearances in a foaming insulator extruded and coated thereby to obtain an insulator small in equivalent dielectric constant. CONSTITUTION:Projected pins 8 are provided at the forward end of the extrusion port side of a core bar 5 provided in the crosshead 2. A resin containing a foaming agent is extruded and applied uniformly on the outer periphery of a traveling conductor 9. At the time when the resin leaves a mouth piece 6, foaming occurs, and further the flow of the resin 3 is prevented by the pin 8 and a foaming insulator 10 formed with clearances 11 is obtained. |
