Experimental Study Of Permanent Magnetic Field Finishing Based On Spherical Magnetic Abrasives

Magnetic abrasive finishing (MAF) is a promising new process finishing. With magnetic field theory applied to traditional polishing skills, it helps to improve surface quality of products sufficiently.In the actual machining process, the difficulty of producing automation, inferior quality of products, low manufacturing efficiency and environmental pollution are problems to be solved. To improve performance and efficiency of magnetic abrasive finishing and to enhance its practical applicability, in this paper, the permanent magnetic abrasive finishing system is theoretically analyzed and the experimental prototype developed; with spherical magnetic abrasives produced based on gas atomization-rapid solidification theory and316L stainless steel and S136tool steel widely used in industry, the relative experiments are carried out.This work includes:1. Theoretical analysis of MAFIn this paper, micro-cutting and extrusion, plastic deforming and corrosive wear are proposed as principles of Magnetic Abrasive Finishing. The property of spherical magnetic abrasives which refer to its micro cutting edge with the same height is studied to help enforce the machining performance. The force analysis of magnetic abrasive and work piece is carried out in detail to gain cutting, extrusion and grind performance on the work piece surface resulted from the three kinds of motion state-cutting, rolling and sliding-of magnetic abrasive. At the same time, based on metal cutting principle and metal plastic making principle, the mathematical expressions of metal removal amount M and working surface roughness Ra which play an important role in forecasting the machining quality and efficiency are put forward.2. Design and analysis of permanent magnetic poleThe magnetic abrasive finishing can be conducted on the ordinary machine tool with magnetic-field-producing device fixed on the principal axis. With electromagnetic pole replaced by NdFeB permanent magnetic pole and the magnetic pole surface slotted, the magnetic abrasive finishing device is remade, and because the magnetic coil is not used, it has advantages such as simple structure, energy saving and environmental protection and high applicability. A large amount of data of experimental tests is got to justify the reliability of permanent magnetic field system.3. Experimental study of MAF on316L stainless steel and S136tool steelWith spherical magnetic abrasives produced based on gas atomization-rapid solidification theory and316L stainless steel and S136tool steel widely used in industry, the relative experiments are carried out. The theoretical analysis and quantitative study are conducted taking kinds of technological parameters which influence the machining performance into the consideration in order to optimize the working condition. It helps to popularize the magnetic abrasive finishing application.