CO2 laser welding using adjustable twin-spot optics

Laser welding using twin spots has been accepted in many industrial production applications. Recently, development centers have received more inquires regarding twin-spot applications. The twin-spot with fixed separation distance has its limitation in certain applications. Every application may require different separation distance and even different focus positions. Therefore, there is a need for developing an adjustable twin-spot optics. This paper shows the design process of an adjustable twin-spot optics for laser welding with high power CO2 lasers. The optics can be adjusted in a way that the distance between the two spots can be changed. The angle from the centerline of each beam to the z-axis from the optical design is 14.5(0). The welding trial on a lap joint showed that it can be welded with the 0-focus position for one laser beam and 2mm beneath the surface for the other. It can also be welded with a spot distance of 2.5mm and more for both symmetrically and asymmetrically.