Patent EP-1927424-B1 (EP)
Title: Device for built-up welding of a concave surface of a  workpiece through injection of material and laser energy
Inventor: DEZERT DIDIER
IPC: B23K26/34
Filed: 2007-11-29
Granted: 2010-12-29
Abstract: The device for replacing a concave side (2) of a tubular part (1) using a material and laser energy, comprises laser diodes (4) for generating a laser beam, units for providing a replacing material (5) near a zone on the concave side, a laser beam conveying device, and a laser beam steering device. The laser beam conveying device leads the laser beam on a length along a direction of penetration. The steering device deviates the laser beam according to a radial direction perpendicular to the direction of penetration. The replacing material is made of a refractory hard material. The device for replacing a concave side (2) of a tubular part (1) using a material and laser energy, comprises laser diodes (4) for generating a laser beam, units for providing a replacing material (5) near a zone on the concave side, a laser beam conveying device, and a laser beam steering device. The laser beam conveying device leads the laser beam on a length along a direction of penetration. The steering device deviates the laser beam according to a radial direction perpendicular to the direction of penetration. The replacing material is made of a refractory hard material and a metal alloy. The laser beam conveying device and laser beam steering device comprise a first convergent lens of which optical axis is tilted depending on the direction of penetration and which receives the laser beam from the laser diode, a mirror that receives the laser beam obtained from the first convergent lens and that reflects the beam according to the radial direction, and a second convergent lens that receives the laser beam from the mirror and converges the laser beam near refilling zone. An interposed optical device makes the laser beam to diverge resulting from laser diodes depending on the direction of penetration in vicinity of an object focal point of the first convergent lens. An optical fiber is arranged for collecting the laser beam resulting from laser diodes and conveying to the object focal point of the first convergent lens. The interposed optical device comprises a third and a fourth convergent lens near the object focal point of the first convergent lens. The third convergent lens receives the laser beam obtained from the fourth convergent lens. The laser diode is placed near object focal point of the fourth convergent lens. The image focal point of the third convergent lens coincides significantly with the object focal point of the first convergent lens. The fourth convergent lens is significantly perpendicular to the direction of penetration and parallel to the radial direction. The second convergent lens and fourth convergent lens are placed radially on both sides of the direction of penetration. An additional mirror is arranged for receiving the laser beam from the fourth convergent lens and reflecting the laser beam depending on the direction of penetration. The optic fiber is laid in roller of a rolling device. The interposed optical device, the first convergent lens and the mirror are comprised in a hollow confinement tube with a double wall in which coolant circulates a fluid. The optical axis of the second convergent lens coincides significantly with the radial direction. The replacing material providing units comprise a cone shaped nozzle in an internal wall with a point directed towards an exit. A tip of the nozzle is pierced thus forming an outlet opening that is significantly coaxial to the optical axis of the second convergent lens. A mandrel is arranged to rotate the tubular part. A primary displacement unit is arranged to ensure a relative displacement depending on the direction of penetration between a tubular part and a subset. A second displacement unit is arranged to ensure a relative displacement according to a radial direction between the tubular part and the subset.