| 摘要 |
PROBLEM TO BE SOLVED: To solve such a problem of switching devices, e.g., magnets and relays, that the life of contacts is shortened because compaction progresses for the purpose of enhancement in user friendliness of apparatus, and the shape of contacts themselves is designed smaller in response to the request of cost reduction.SOLUTION: When obtaining a polygonal electrical contact material by press punching, press punching is performed while providing an angle R of 0.3-3.0 at corners, thus suppressing occurrence of fine cracking or chipping at corners. Furthermore, fine cracking or chipping which occur during press punching is prevented from developing to larger cracking or chipping due to expansion during internal oxidation processing. |
