Study On Laser Cladding Remanufacturing Repair Method Of Gear Tooth Surface

Laser cladding is widely used in the repair and surface modification of various complex parts as an advanced surface treatment technology.At present,the application of laser cladding technology is mainly focused on the research of horizontal substrate.However,the actual surface of the parts to be repaired often interferes with the laser head due to the complex shape,which leads to the repair cannot be carried out.It is difficult to guarantee the shape precision of gear tooth surface repaired by conventional cladding technology because of its structural characteristics.In order to solve these problems,the morphology of single cladding layer and the surface quality of multiple cladding layers on the inclined substrate were studied,and the cladding scheme on the gear tooth surface was proposed.The specific research methods and results are as follows:Based on the study of the power density distribution of laser spot and the laser energy attenuation caused by the coupling of laser and powder on the inclined substrate,an analytical model of the width and height was established according to the principle of conservation of energy and mass,and the model was verified by single factor test.The effects of process parameters and tilt angle of the substrate on the cladding layer morphology were also investigated.The results show that the width of the cladding layer is mainly affected by the laser power,and the height is mainly affected by the scanning speed and the powder feeding rate.When the process parameters are constant,the width of the cladding layer increases with the increase of the tilt angle,and the height decreases with the increase of the tilt angle.Multiple cladding experiments were carried out on the inclined substrate by changing the tilt angle and scanning path respectively to explore the influence of the two on the surface quality of the cladding layer on the inclined substrate.The test results show that the surface flatness of multi-track cladding layer increases with the increase of the tilt angle of the substrate,but too large tilt angle will cause the apparent defect of the cladding layer.The scanning path will affect the heat input and heat diffusion in the cladding process,resulting in that the dilution rate of the cladding layer lapped along the downhill direction of the substrate is greater than that of the cladding layer lapped along the uphill direction of the substrate.When the lap direction is the same,the cladding layer surface flatness obtained by reciprocating scanning is higher than that obtained by unidirectional scanning,and when the scanning method is fixed,the cladding layer surface flatness obtained by overlapping along the downhill direction of the substrate is higher.The cladding of the tooth surface of a single gear tooth was carried out in the form of piecewise,and the position of any point on the involute was determined by establishing the rectangular coordinate equation of involute,so as to complete the multi-lap cladding of involute tooth profile.The method of skipping tooth scan combined with proper number of teeth can make the heat evenly distributed during cladding and avoid deformation of the gear tooth caused by heat accumulation.The experiment of repaired gear was carried out by using different combination of process parameters.The results show that the tooth surface profile after cladding is close to the original profile,and the surface is relatively smooth.