| 摘要 |
PROBLEM TO BE SOLVED: To provide a technique for determining the welding state of a noble metal chip to an electrode by laser welding, by a simpler method.SOLUTION: The method of manufacturing a spark plug by welding a noble metal chip to at least one of a center electrode and a ground electrode includes a welding step for welding an electrode and a noble metal chip by irradiating a portion of the boundary of a noble metal chip and an electrode, to which the noble metal chip is bonded, with laser and then moving the part irradiated with laser relatively, and a determination step for determining the welding state of the noble metal chip based on the difference of the position of a noble metal chip at a first timing, and the position of a noble metal chip at a second timing, in a period before starting the welding step and after ending the welding step, via the welding step. |
