Advantages of adaptive optics for laser metal deposition in comparison to conventional optics

Abstract

Laser Metal Deposition with adaptive optics and zoom-optics allows variable beam diameters at a constant working distance guarantying a constant powder focus on the work piece surface. The zoom-optic presented in this paper is an alternative if a variation of the laser beam diameter for producing different track widths is needed. The extensive adjustment of a powder nozzle to the working point (Tool Center Point) is unnecessary with a fixed working distance. The variation of the laser beam diameters is generated by adjusting the lens positions. In the interaction zone the laser beam diameter can be varied from d = 0.6 mm to d = 2.4 mm. The power density distribution produced corresponds as closely as possible to a top-hat distribution which is best for Laser Metal Deposition. Two examples using this zoom-optic are presented. In a first application an increase of the productivity of a two-dimensional cladding is demonstrated by cladding an outer frame with a lower and an inner filling with a higher deposition rate. In a second application laser metal deposition of a simulated blade tip is carried out using a variation of the laser beam diameter and adaption of laser power during the cladding.Laser Metal Deposition with adaptive optics and zoom-optics allows variable beam diameters at a constant working distance guarantying a constant powder focus on the work piece surface. The zoom-optic presented in this paper is an alternative if a variation of the laser beam diameter for producing different track widths is needed. The extensive adjustment of a powder nozzle to the working point (Tool Center Point) is unnecessary with a fixed working distance. The variation of the laser beam diameters is generated by adjusting the lens positions. In the interaction zone the laser beam diameter can be varied from d = 0.6 mm to d = 2.4 mm. The power density distribution produced corresponds as closely as possible to a top-hat distribution which is best for Laser Metal Deposition. Two examples using this zoom-optic are presented. In a first application an increase of the productivity of a two-dimensional cladding is demonstrated by cladding an outer frame with a lower and an inner filling with a higher deposit...