Modeling of material removal in magnetic finishing based on Maxwell's stress tensor theory and its experimental validation

Magnetic finishing is an extremely suitable process for processing high quality surface aluminum alloy mirrors due to the low damage. Obtaining an accurate removal function is essential to achieve a controlled finishing of aluminum alloy mirror. In this study, the magnetic field between the magnetized abrasive particles was simplified by equivalent substitution method after modeling the geometry of the abrasive and simulating its magnetic field. Distribution of finishing pressure was calculated based on Maxwell's stress tensor theory. Distribution of the finishing pressure was uneven, and the finishing pressure in the center of the finishing area was about 10 times that of the edges. And the removal amount was calculated with Preston's equations. The experimental results of the removal amount show that the removal amount increases and then decreases as the magnetic abrasive content in the abrasive decreases. The removal amount has a negative correlation with the finishing gap. Stronger magnetic fields can increase the removal amount. After 10 minutes of machining, the surface roughness Ra of the aluminum plate decreased from 0.189 μ m to 0.030 μ m . The relative error is less than 7% compared to the simulation results when the finishing gap is 2-3 mm. The removal depth experimental results show that the maximum removal depth reaches 117 nm after 10 minutes of machining at 950r/min, with a relative error of 3.5%. This accurate removal function can provide a theoretical basis for achieving controlled magnetic finishing.