Patent ID: 8399799
Filing Date: 2013-03-19
Classification: B23K,H01T

Abstract:
1. A method for manufacturing a spark plug, the spark plug comprising: a center electrode comprising a center electrode base member and a center electrode noble metal tip welded thereto by means of a laser; and an outer electrode having an outer electrode base member and an outer electrode noble metal tip welded thereto by means of a laser, or an outer electrode base member, a tip base member joined thereto, and an outer electrode noble metal tip welded to the tip base member by means of a laser, said method comprising: a laser welding process for subjecting to laser welding by use of a laser beam: wherein the laser beam has a BPP value of 25 mm·mrad (a radius·a half angle) or less at a time point when the laser beam enters a transfer optical system for guiding laser beam to an area to be welded, and wherein a BPP value achieved at a time point when the laser beam used for laser-welding the outer electrode base member and the outer electrode noble metal tip or the tip base member and the outer electrode noble metal tip enters the transfer optical system is smaller than a BPP value achieved at a time point when the laser beam used for laser-welding the center electrode base member and the center electrode noble metal tip enters the transfer optical system.