Femtosecond laser ablation characteristics of spiral bevel gear material 20CrMnTi

As a new type of gear transmission structure, spiral bevel gear transmission is the key component to realize spatial intersecting or staggered transmission. It has the advantages of large overlap degree, strong bearing capacity and smooth transmission. China has independently developed a six axis five linkage CNC gear milling machine for spiral bevel gear manufacturing, and has manufactured the largest spiral bevel gear grinding machine in the world. Deng Xiaozhong et al. Developed a basic system for automatic identification of tooth surface error by studying the relationship between the motion parameters of machine tool and tooth surface error, and established the correction model of motion parameters of four axis CNC gear milling machine. The machining accuracy of domestic spiral bevel gears can only reach 4 ~ 5 grades, which is about 2 grades lower than that of foreign countries. Traditional machining methods such as mechanical grinding and milling restrict the development direction of high quality and high precision of spiral bevel gears, and affect the service life and performance of spiral bevel gears. Therefore, it is necessary to explore new precision manufacturing methods.

For spiral bevel gear machining tooth surface characteristics, Liang Zhiqiang and others studied the surface morphology after grinding. Through white light interferometer observation, with the increase of grinding depth, the scratch on the gear surface gradually deepened, the quality of the grinding tooth surface decreased, and the temperature of the tooth surface during grinding was high, which was easy to produce grinding burns, cracks and other defects, which seriously affected the surface roughness and surface roughness Tooth surface accuracy. Wang Yanzhong et al. Studied the residual stress existing on the tooth surface in milling process. With the increase of cutting depth, the residual stress gradually accumulates, which has a certain impact on the cutting quality and performance of gear.

Femtosecond laser processing technology is a new processing method. Compared with long pulse laser processing, femtosecond laser processing can remove materials with high peak power and short action time. The heat affected zone is small during ablation. It has the characteristics of accurate processing area, flexible processing method and high processing precision. It has been applied to large area ablation of alloy materials. In this paper, femtosecond laser processing technology is used to process the final process of spiral bevel gear material with micron machining allowance. The femtosecond laser ablation characteristics of gear material 20CrMnTi are studied through energy coupling model simulation and experiment.