| 摘要 |
PURPOSE:To eliminate the occurrence of cracking of a base material in and after production thereof and improve the yield, by removing a dummy rod at a specific time of a collapsing step in jacketing a glass pipe around the outer periphery of a glass rod of core. CONSTITUTION:A dummy rod 12 at one end of a glass rod 11 is mounted on a chuck of a glass lathe, and a glass pipe 13 at the other end is mounted and supported on the glass lathe respectively. The left and right ends of the pipe 13 are set respectively at the starting and completing ends of the heat shrinkage. The rod 11 and pipe 13 are synchronously rotated in the direction of (R), and the pipe 13 is heated by a heater 15 moving in the direction (X). The interior of the pipe 13 is decompressed by a vacuum suction means to start the heat shrinkage of the pipe 13 at the same time to heat fuse the pipe 13 to the rods 12 and 11 one after another. When the heat fusion region goes over the boundary part of the rods 11 and 12, the rod 12 is cut by fusion and removed from the mutual heat fusion part of the rods 11 and pipe 13. A supporting rod 16 is then heat fused to the removed end part to support the end part. The rod 11 and pipe 13 are then integrated by movement of the heater 15 to cut the right end part of the pipe 13 by fusion, and the aimed base material 17 is obtained by removing strain. |
