The Research Of Three-dimension Laser Galvanometric Scanning System In SLS

Galvanometric laser scan technology is widely used in the field of laser processing.In order to obtain a good processing quality,the laser beam must be small and uniform on the entire working surface.Due to the error of the out of focus,the traditional laser focusing system focus on the curved surface,the more deviation from the focus center,the facula is more divergent,seriously affecting the quality of the focus.Usually adopt dynamic focusing optical system to compensate defocus error,this paper proposes a dynamic focusing system,which uses the principle of the optical lever to compensate the deviation of the deviation.Do the theoretical analysis and simulation design of scanning system design first,followed by a large number of experiments.Within the range of the working space of 400mm*400mm,work height of 750 mm,the biggest spot diameter is 0.432 mm,and thus bound spot in the whole working surface small and uniform,it is proved that the system can be used for selective laser sintering(SLS)feasibility.First,determine the overall scheme of the scanning galvanometer system in this paper,through the analysis of principle of scanning galvanometer system and defocus error sources were analyzed,this paper proposes a dynamic focusing system,using optical lever principle to compensate the defocus error.Then do the optical design of the scanning mirror system,parameters are calculated by geometrical optics to determine the initial structure,and then use of optical components to optimize the optical design software,through the analysis and evaluation of image quality,the system reaches the design index;the lenses and the mechanical structure are processed by CAD plus.then the paper selected laser source and beam quality analyzer for analysis of laser beam quality and focusing performance.Secondly,a scanning galvanometer is selected from the designed dynamic focusing opticalsystem,and the scanning galvanometer control card is studied.Then do a detailed study of the galvanometer scanning pillow distortion error principle and mathematical model,and puts forward the method of correcting pillow type model.Besides,the paper study the influence of scanning precision distortion of other nonlinear correction method is proposed for software.