Research On Femtosecond Laser Micro Correction Face Gear Based On Dynamic Effect

In recent years,with the rapid development of lightweight aerospace vehicles,the application advantage of face gear is more and more obvious.However,due to the lack of mature manufacturing technology of high-precision face gear processing machine tools in China,it is difficult to process high-precision face gear with traditional machining methods.In addition,due to the strict blockade of foreign countries,it is urgent to develop innovative processing methods to reduce the gap between domestic and foreign countries.The difficulty of machining high-precision face gear is that the tooth surface is complex and precise,and femtosecond laser processing can achieve micron or even nanometer level precision machining,the processing area is very accurate,and the thermal effect is very small.Aiming at the last femtosecond laser micro correction process of face gear,this paper adopts the method of theoretical modeling,simulation and experimental analysis to carry out the research on femtosecond laser micro correction of face gear,which mainly includes the following contents:Study on ablation characteristics of face gear materials by single pulse femtosecond laser.The ablation threshold of 18Cr2Ni4 WA was calculated by measuring the laser power and analyzing the loss;According to the change law of the reflection,absorption and transmission process of the laser beam irradiating the material surface,the absorption coefficient of the material is obtained.Dynamic effect and modeling simulation of multi pulse femtosecond laser micro correction.There are many kinds of dynamic effects,but only the energy accumulation effect and the defocusing effect are studied.Considering the energy accumulation effect,the energy density of multi pulse laser irradiation is obtained;According to the nonlinear effect of defocusing amount on ablation rate,the distribution of energy density on the beam cross section with defocusing amount changing is analyzed;Combined with the coupling effect of energy accumulation effect and variable defocusing amount effect,the energy density model of face gear material absorption,the quantitative relationship between ablation pit diameter,ablation pit depth and pulse number are obtained,and the simulation analysis is carried out.The experimental study of femtosecond laser ablation face gear material morphology characteristics.The experiment of femtosecond laser ablating surface gear material was carried out,and the ablation pits were detected to study the influence of laser power and pulse number on the morphology characteristics of multi pulse femtosecond laser ablated pits.The experimental results show that the quality of femtosecond laser processing increases with the decrease of laser power.When the laser power is low,there is no obvious molten residue in the ablation pit,the profile of the ablation pit is smooth,and the femtosecond laser processing quality is good enough,but the recast layer can not be avoided.The experimental results also verify the rationality of the theoretical model.Research on the measurement of tooth surface error and femtosecond laser micro correction technology.The tooth surface error of the face gear is measured by the gear measuring center,and the femtosecond laser corrected thickness of the face gear is confirmed by the difference surface method;The femtosecond laser processing system is used to micro correction face gear.The laser processing installation and femtosecond laser scanning path planning of the face gear are determined.Aiming at the recast layer of femtosecond laser,the second processing of femtosecond laser processing surface is proposed to remove the recast layer and ensure the quality of the tooth surface after femtosecond laser micro correction.