RESUMEN
Thin-walled bearings are widely used owing to the advantages of their light structure, high hardness, and strong load-carrying capacity. However, thin-walled bearings are often prone to deformation during the machining process, which can seriously affect the performance of the bearings. In addition, the machining deformation and quality of bearings are difficult to balance. To address the above issues, this paper investigates the effects of the machining parameters on the machining deformation, surface quality, and machining efficiency of a thin-walled bearing during the roughing stage. The dynamic balance between deformation inhibition and high quality in rough grinding was studied, and the optimal parameters for thin-walled bearing outer ring grinding were obtained. The deformation mechanism of thin-walled bearings caused by grinding was revealed through simulation and experimental analysis. The results show that the machining deformation and quality reach a balance when the workpiece speed is 55 r/min, the grinding wheel rotational speed is 2000 r/min, and the feed rate is 0.1 mm/min. Deformation increases with the increase in workpiece speed and grinding wheel speed. At the same time, the surface roughness increases with the increase in the workpiece speed, but the increase in the wheel speed will improve the surface roughness. As the workpiece speed increases, the surface topography shows a more pronounced stockpile of material, which is ameliorated by an increase in grinding wheel speed. As the rotational speed of the workpiece increases, the number of abrasive grains involved in the process per unit of time decreases, and the surface removal of the workpiece is less effective, while the increase in the rotational speed of the grinding wheel has the opposite effect. The grinding deformation of thin-walled bearings is mainly induced by machining heat and stress. As the rotational speed increases, the heat flux in the grinding zone increases. More heat flux flows into the surface of the workpiece, causing an increase in thermal stresses on the inner surface of the bearing collar, leading to greater deformation. The temperature in the grinding area can be reduced during machining, realizing a reduction in deformation. The research content contributes to the balance between high quality and low distortion in machining processes.
RESUMEN
NdFeB materials are widely used in the manufacturing of micro-linear motor sliders due to their excellent permanent magnetic properties. However, there are many challenges in processing the slider with micro-structures on the surface, such as complicated steps and low efficiency. Laser processing is expected to solve these problems, but few studies have been reported. Therefore, simulation and experiment studies in this area are of great significance. In this study, a two-dimensional simulation model of laser-processed NdFeB material was established. Based on the overall effects of surface tension, recoil pressure, and gravity, the temperature field distribution and morphological characteristics with laser processing were analyzed. The flow evolution in the melt pool was discussed, and the mechanism of microstructure formation was revealed. In addition, the effect of laser scanning speed and average power on machining morphology was investigated. The results show that at an average power of 8 W and a scanning speed of 100 mm/s, the simulated ablation depth is 43 µm, which is consistent with the experimental results. During the machining process, the molten material accumulated on the inner wall and the outlet of the crater after sputtering and refluxing, forming a V-shaped pit. The ablation depth decreases with the increment of the scanning speed, while the depth and length of the melt pool, along with the height of the recast layer, increase with the average power.
