Abstract: A laser processing head includes a laser irradiation part, a collimating optical system for collimating laser light from the laser irradiation part, and a collecting optical system for collecting the laser light after passing through the collimating optical system. An optical system including the collimating optical system and the collecting optical system is configured such that the laser light after passing through the collecting optical system has coma aberration.

Abstract: A laser processing head includes a laser irradiation part, a collimating optical system for collimating laser light from the laser irradiation part, and a collecting optical system for collecting the laser light after passing through the collimating optical system. An optical system including the collimating optical system and the collecting optical system is configured such that the laser light after passing through the collecting optical system has coma aberration.

Abstract: A welding determination device includes: a measurement unit configured to measure temperature of a joint portion between strip-shaped sheets (for example, steel strips (2)) to be joined by seam welding; and a determination unit configured to, based on measurement results by the measurement unit, calculate an average temperature Tave of the joint portion and a temperature difference ?T that is a difference between a maximum value and a minimum value among temperature of the joint portion and, when the average temperature Tave is less than or equal to a first threshold value and the temperature difference ?T is more than or equal to a second threshold value, determine that a joining defect due to ineffective current has occurred at the joint portion.

Abstract: A welding apparatus including: a welding unit (20) that includes a pair of electrode wheels (21A, 21B) arranged to face each other with a welding object therebetween; a pressing unit (30) that includes a pair of press rolls (31A, 31B) that are arranged to face each other with the welding object therebetween and press a welded portion of the welding object welded by the electrode wheels (21A, 21B); a cooling unit (40) that supplies a cooling medium toward the welded portion pressed by the press rolls; a heating unit (50) that heats the welded portion cooled by the cooling unit (40); and a moving body (10) that supports the welding unit (20), the pressing unit (30), the cooling unit (40), and the heating unit (50), and reciprocates in a welding direction of the welding object.

Abstract: The purpose is to determine occurrence of expulsion in seam welding with high accuracy. A welding determination device includes: a measurement unit configured to measure temperature of a joint portion between strip-shaped sheets (for example, steel strips) to be joined by seam welding; and a determination unit configured to, based on a measurement result by the measurement unit, calculate an average temperature Tave and a temperature difference ?T of the joint portion and, when the average temperature Tave is more than or equal to a first threshold value that is set according to the sheet thickness of each of the strip-shaped sheets and the temperature difference ?T is more than or equal to a second threshold value, determine that expulsion has occurred at the joint portion.

Abstract: A welding apparatus including: a welding unit (20) that includes a pair of electrode wheels (21A, 21B) arranged to face each other with a welding object therebetween; a pressing unit (30) that includes a pair of press rolls (31A, 31B) that are arranged to face each other with the welding object therebetween and press a welded portion of the welding object welded by the electrode wheels (21A, 21B); a cooling unit (40) that supplies a cooling medium toward the welded portion pressed by the press rolls; a heating unit (50) that heats the welded portion cooled by the cooling unit (40); and a moving body (10) that supports the welding unit (20), the pressing unit (30), the cooling unit (40), and the heating unit (50), and reciprocates in a welding direction of the welding object.