| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of manufacturing a spark plug in which a ground electrode can be prevented from being damaged when removing a welding projection formed at a jointportion between the main metal fittings and the ground electrode. SOLUTION: A removing punch 320 in which a cutting blade 322 has been formed by notching a part of the tip part 325 worked in a tapered shape is fixed to a slide mechanism 330 in a state that its cutting edge is turned downward, and descended toward the main metal fittings 50 to which the ground electrode 30 is joined. By being guided to a slope 321 of the removing punch 320 contacted with the inner peripheral edge on the side opposite to the side on which a welding projecting part 80 of the tip face 57 has been formed, the cutting edge of the cutting blade 322 is positioned to the welding projecting part 80. Since even against a metal fittings assembly 200 of which the tip part 31 of the ground electrode 30 is inclined to the inner peripheral side of the main metal fittings 50, the cutting edge is positioned at the welding projecting part 80 so as to evade the tip part 31, the welding projecting part 80 can be cut without damaging the ground electrode 30. COPYRIGHT: (C)2007,JPO&INPIT
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