Experimental study on vibration-assisted magnetic abrasive finishing for internal blind cavity by bias external rotating magnetic pole

The work aims to solve the finishing problem of blind cavities and grooves in the internal channel of 3D printed parts. Based on the principle of vibration-assisted magnetic abrasive finishing (VMAF), a novel scheme of the bias external rotating magnetic pole (BERMP) was proposed, where the spherical steel grit (SG) was used as the magnetic abrasive to extrude, impact and rub the surface of the workpiece to realize finishing. And then, its feasibility was verified by theoretical and experimental methods. The response surface method (RSM) was used to establish a quadratic regression equation model to reveal the influence of processing clearance, magnetic pole rotation speed, vibration frequency and amplitude on surface roughness and obtain the optimum processing parameters. After processing the specimen under the conditions of 1 mm of processing clearance, 800 r/min of magnetic pole speed, 15 Hz of vibration frequency and 0.2 mm of vibration amplitude, the Ra decreased from original Ra12.60 mu m to Ra1.25 mu m with the reduction by 90%, improving the surface quality of the workpiece remarkably. The research results can provide a theoretical basis and technical reference for finishing irregular parts with complex cavities.