Method for manufacturing spark plug

A method for manufacturing a spark plug comprising the steps of:

• providing a center electrode;
• providing an insulator disposed externally of an outer circumference of the center electrode;
• providing a metallic shell disposed externally of an outer circumference of the insulator
• providing a ground electrode whose one end portion is joined to the metallic shell and whose other end portion faces the center electrode;
• providing a first tip which forms a gap in cooperation with the ground electrode or the center electrode, said first tip being disposed at the center electrode and/or the ground electrode and being joined to a tip-mating member;
• and
• transferring the first tip to a joining position where the first tip is joined to the tip-mating member, wherein
• the transfer step comprises a step of performing positional correction for the first tip before the first tip reaches the joining position and further comprising:
• (a) a step of moving, by use of a first feed device, the first tip to a middle position between a feed position where the first tip is fed, and the joining position;
• (b) a step of performing positional correction for the first tip at the middle position by gripping the first tip using a position-correcting chuck which grips the first tip;
• and
• (c) a step of, after the positional correction, moving the first tip from the middle position to the joining position by use of a transfer chuck, with the first tip being chucked with the transfer chuck,
• the first feed device and the transfer chuck are configured such that transfer is repeated with a horizontal distance therebetween being fixed:
• there are simultaneously performed:
• a first moving process in which, in the step (a), the first feed device moves one first tip from the feed position to the middle position, and
• a second moving process in which, in the step (c), the transfer chuck moves another first tip from the middle position to the joining position, and
• the positional correction in the step (b) is performed in the course of return of the first feed device from the middle position to the feed position and in the course of return of the transfer chuck from the joining position to the middle position.