| 摘要 |
PURPOSE:To manufacture a core which has high size precision and less eccentricity, and to improve mass-producibility and quality, by packing plastic in a cavity by jettison. CONSTITUTION:At the center part of one end surface of a columnar rod 25, a circular hole 26 which has a diameter nearly equal to that of an optical fiber wire and is nearly free of eccentricity from the external diameter of the rod 25 is formed. After a small rod 27 is inserted into the circular hole 26, the rod 25 is dipped in an electrocasting bath vessel 29 to perform nickel electrocasting. Once electrocast layers 32 having prescribed thickness are formed around the external circumferential surfaces of the rods 25 and 26, they are taken out of the bath vessel 29 and the rod 25 is extracted from the electrocast layer 32 to obtain a hollow electrocast metallic mold 33. The metallic mold 33 form a core forming metallic mold 35 with a couple of metallic molds 35A and 35B and a pipe 40. Then, plastic heated and molten through a spool, a runner, and gate provided at optional positions of the metallic mold 35A is packed in a cavity 36 by jettison to form a core 20. |
