| Magnetic abrasive finishing is a precision processing technology that can effectively apply the magnetic field to the polishing of part surface and can achieve finishing flat, free-form surface and the surface of the rotor.The efficiency of finishing directly impact on the magnetic abrasive finishing quality and range of applications.Especially in difficult materials’ finishing such as stainless steel, the processing efficiency is particularly important.Firstly,this paper will use theoretical calculation to improve the efficiency of magnetic abrasive finishing plane processing.we design magnetic pole to magnetic abrasive finishing stainless steel sheet by theoretical analysis and simulation.Then we take experimental study of application of new designed poles to finishing the surface of 304 stainless steel sheet.The main contents are as follows:1.The theory analysis of improve the magnetic abrasive’s machining efficiency.By preston empirical formula,the material removal efficiency is proportional to the pressure of abrasive grain and the relative velocity of theworkpiece and the abrasive grains. The force of magnetic brush and the velocity of abrasive plunging was analyzed and calculated when finishing flat workpieces. We can clear find that both are influenced by the size of the magnetic induction in large degree.so through the design of good magnetic poles can effectively improve the efficiency of abrasive finishing.2.Simulation and design of distributed permanent magnet poleThrough comparative analysis, we choose excellent performance NdFe B as the material of magnet pole. First of all, the size of the magnetic pole is designed by the circuit law. Then, we simulate and analysis the permanent magnetic pole by using ANSYS Maxwell, found the ring pole’s magnetic leakage is more serious, and the distributed permanent magnet pole is better in magnetism gathering. Then, through the simulation and analysis,we design the size,the spacing and the slotted size of small pole. Eventually,we use the distributed permanent magnet pole as the pole of magnetic abrasive finishing of stainless steel sheet,the main magnetic materials is nylon, and the small mosaic magnetic pole is radius of 10 mm, height 8mm cylinder.The gap between the small magnetic pole of the adjacent cylinder is 35 mm,magnetic pole surface open rectangular groove along the circumferential and the length and width of the rectangular groove are 2mm.Finally, the magnetic field strength of the distributed permanent magnet pole in the processing area is measured, and the magnetic field intensity of the machining area is stronger when four small magnetic poles are inlaid.3.Experimental study on the processing of stainless steel sheet by distributed magnetic pole.First, the experimental verification using the distributed permanent magnet pole can improve the efficiency of magnetic abrasive finishing. Then,the influence of various process parameters on the surface roughness of workpiece is studied. Then, we use four factors and three levels orthogonal experiment to study the degree of relationship between the type of abrasive phase, spindle speed, abrasive particle size and machining gap on the influnce of the results.The optimal factor level combination scheme of the magnetic abrasive finishing stainless steel plate is found out, and the scheme is verified by experiments.4. The micro hardness of the stainless steel plate with magnetic abrasive finishing was studied.First, we experimentally studied the change of 304 stainless steel sheet surface mico hardness along with the processing time using Hm-102 Vickers hardness measurements.Then, the change of micro hardness in the depth direction of the processed workpiece is obtained by measuring.We analyzed the hardening phenomenon of magnetic abrasive finishing stainless steel. |
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