Laser welding head for sleeve-to-tube welding

Sleeve is welded inside a tube by expanding the sleeve to fit closely within the tube, positioning a weld head having a focusing lens, mirror, and spring biased focal arm, adjacent to the weld area and directing a high power laser beam onto the welding head. Focusing and reflecting the beam onto the weld area, and rotating the weld head at a speed of between 4.0 and 7.5 rpm around the weld fusion path to weld the sleeve to the tube. The weld area is shielded with shield gas, and the laser beam operated at between 500 to 700 watts. A laser welding head rotates for welding a sleeve within a tube by fusing the interface between the sleeve and tube with a laser beam uses a focusing lens for focusing a laser beam transmitted through a housing which is inserted inside of the sleeve; a welding mirror directs the focused beam out of the housing and into contact with the sleeve, and is maintained a predetermined distance from the inside surface of the sleeve. Shield gas is supplied to the weld area and passes about the periphery of the focusing lens for cooling the focusing lens and the welding mirror. A recessed aperture is provided within the discharge outlet to prevent molten material from the weld site from splattering into the housing and onto the mirror or lens. Multiple discrete weld paths or continuous overlapping helical weld paths at each end of the sleeve are preferred. The laser delivers 500 to 700 watts to the weld area, and causes a fusion width of at least .1125 mm and penetrates the tube to a depth of about 6 mm.