| 摘要 |
PURPOSE:To enable high frequency welding to be achieved and to prevent the occurrence of spark by making a part or the surface of one or both of two electrodes with an electric insulator. CONSTITUTION:When a hollow formed product 1 is inserted into between sheet like plastics 2 and three dimensional welding part is formed, the projected portion 7b for forming a thin wall is made of the melted and sintered material of alumina which is an electric insulator, and is connected to a high frequency electrode 5 and then this electrode is used for welding. A thin wall part 3 may be formed without the occurrence of spark entirely. As current flows between the electrode 5 and an earth electrode 6, the adjacency of the projected insulator 7b opposing to the thin wall part 3 is sufficiently heated by transmitted heat, whereby superior welding condition is kept and the thin wall part 3 may be formed. |
