| 摘要 |
PROBLEM TO BE SOLVED: To realize a ball forming device which prevents both discharge from migrating and abnormal discharge from occurring by a method wherein a discharge electrode is covered with an insulating cover, and a prescribed gap is interposed between the discharge part of the electrode and the insulating cover. SOLUTION: An electric torch 6 is equipped with a torch rod 61, a torch holder 62 which holds, the torch rod 61, and a cover 63 which covers the torch rod 61 and the torch holder 62. The cover 63 is formed of fluororesin, ceramics or the like. The torch holder 62 is made of an insulating material. A positive voltage is applied to a wire 9, and a negative voltage is applied to the torch rod 61, so that a discharge 65 occurs between the wire 9 and the torch rod 61 by a high potential applied between them. The tip of the wire 9 fed from a capillary 4 is melted by a discharge energy to form a ball 9a. By this setup, a discharge 65 is stably concentrated at the tip 61b of the torch rod 61, and a ball 9a of constant diameter can be formed. |
