Welding parts on the circumference is not possible with most welding techniques. Spin friction welding is an option but creates an excessive number of particles. However, it is also possible to weld cylindrical parts on the circumference cleanly and precisely with laser. Either by rotating the parts or by using the special Radial Optics.

With the rotating technique, either the parts are rotated underneath a spot optics in a vertical or horizontal orientation or vice-versa, the optic is rotated around the fixed positions. With rotation, the Spot Optic can also be equipped with a pyrometer for quality and process control. Since no clamping mechanism is involved here, a press-fit between the parts must be considered. Additionally, the outer part to weld needs to be laser transparent while the inner part is laser absorptive to ensure a successful weld.

Today, it is possible with a Radial Optic to weld the circumference of these geometries (i.e., tube to a connector) simultaneously in a single laser shot. The principle is based on a Ring Optic and a conical mirror with an opening in the center. The ring-shaped laser beam is then reflected on this surface to illuminate the entire outer perimeter of the part placed inside the Conical Mirror. The press-fit and orientation regarding laser transparent and laser absorbing of the parts are the same as the rotation process above.

Because the weld between the two cylindrical parts is almost instantaneous, it would be possible to process multiple parts during the same machine cycle. For example, loading the material on a fixture vertically and then using an X, Y, Z servo control unit to align the Radial Optic with each part to weld.