Study On Ablation Characteristics Of Femtosecond Laser Finishing Gears Based On Three-temperature Heat Transfer Model

Face gear has excellent transmission characteristics,with smooth transmission,strong bearing capacity,fast transmission speed,low noise and strong interchangeability and other characteristics,widely used in aerospace,engineering machinery,large precision equipment and other fields.But the tooth shape of face gear is complicated,the technical requirement is high,and the manufacture is difficult.Due to the blockade of high precision gear machining machine tools and precision machining technology in foreign countries,it is urgent to create new machining methods to reduce the gap between domestic and foreign manufacturing levels.Femtosecond laser machining is a new machining method,which has the advantages of precision machining area,low thermal effect and precision machining of any material.It has been widely used in precision manufacturing.Aiming at the femtosecond laser ablation face gear material 18Cr2Ni4 WA,this paper adopts the method of theoretical modeling,simulation and experimental analysis to study the ablation characteristics of femtosecond laser finishing gear,which mainly includes the following content:Study on ablation process and mechanism of femtosecond laser finishing gear.The mechanism of femtosecond laser finishing gear was studied.The physical model and general law of femtosecond laser removing the material were analyzed.The dynamic absorption process of laser energy absorbed by face gear surface was studied theoretically.Based on this,a three-temperature complex coupling model of femtosecond laser ablated face gear material was established.Modeling and simulation of femtosecond laser ablative face gear.Based on the non-Fourier heat transfer phenomenon,the three-temperature coupled heat transfer model of the laser finishing gear was established,and the temperature variation process of the facial gear materials under the electron-spin-lattice monopulse energy effect at different energy densities was simulated.Considering the cumulative effect of multi-pulse laser energy,a three-temperature coupled heat transfer model of multi-pulse laser finishing gear was used to simulate and analyze the ablative temperature variation process of face gear materials,and to study the characteristic parameters such as the diameter and depth of the ablative pits under different energy densities.Experimental study on morphological characteristics of femtosecond laser ablation tooth surface.An experimental platform was built,and combined with the parameter range experiments of simulation,the evolution law of ablative pit morphology and machining tooth surface roughness with the change of energy density under the action of single pulse laser,and the change law of ablative pit depth and diameter under the action of multi-pulse laser were studied,The influence of different sweep path spacing on tooth surface roughness was analyzed.The experimental results show that the depth and diameter of ablative pits increase with the increase of energy density under the action of monopulse laser,and the tooth surface roughness does not continuously improve with the increase of energy density.The continuous accumulation of multi-pulse laser energy will not increase the balance temperature of gear surface,the continuous increase of energy density will not make the ablation pits better,and the tooth surface quality is the best when the scanning path spacing is 25μm.