根据研磨加工的材料去除模型,分析得到增加研磨压力是提高磁力研磨加工效率的可行手段。通过在单纯磁力研磨工艺中引入超声波振动,增加了研磨粒子的瞬时研磨压力。经实验证明,在超声振动辅助磁力研磨加工中,研磨粒子在水平切削和垂直冲击挤压运动的综合作用下,对工件材料的去除率高且表面质量均匀;加工效率较单纯磁力研磨工艺提高了约50%;工件表面粗糙度Ra可降至0.06μm左右;电子显微镜观察发现其加工后工件表面形貌较单纯磁力研磨细密均匀;采用X射线干涉仪检测得知,经超声振动辅助磁力研磨加工后的工件材料(SUS304)表层的应力状态已由原始的残余拉应力+320MPa变为压应力-40MPa,有效提高了工件的疲劳强度。
Based on the material removal model, it was concluded that the increase of finishing pressure was a practicable method for improving the efficiency of the magnetic abrasive finishing. By adding ultrasonic vibration to the magnetic abrasive finishing process, the instantaneous pulsating finishing pressure of magnetic abrasive particles could be increased. Experiment results showed that, magnetic abrasive particles could efficiently remove the workpiece material and keep surface smooth with the combined force in rotational movement and vertical impact. The practical experiment proved that the finishing efficiency was improved by 50% or so. The surface roughness of workpiece decreased to 0.06 μm. Compared with only magnetic abrasive finishing, the ultrasonic vibration-assisted magnetic abrasive finishing made the surface morphology smoother and well-distributed in digital microscope. By using X-ray interferometer detection, the stress state of workpiece surface layer after ultrasonic vibration-assisted magnetic abrasive finishing changed from residual tensile stress ( + 320 MPa) to compressed stress ( -40 MPa) , which effectively improved fatigue strength of workpiece.