Semi Magnetic Abrasive Machining

4th International Conference on Mechanical Engineering, December 26-28, 2001, Dhaka, Bangladesh/pp. V 81-85 SEMI MAGNETIC ABRASIVE MACHINING P. Jayakumar Priyadarshini Engineering College, Vaniyambadi – 635751. (T. N. –India) Magnetic field assisted polishing is an unconventional polishing method which is Abstract capable of generating fine finish on components without any sub-surface damage. This process is suitable not only for polishing external and internal surfaces also for complex shaped components. Magnetic field assisted polishing can be classified into two types. They are Magnetic Abrasive Machining (MAM) and Semi Magnetic Abrasive Machining (SMAM). In MAM, abrasives such as Aluminium Oxide (Al2O3) and Silicon Carbide (SiC) are conglomerated with ferromagnetic iron particles of definite ratio. This conglomerate is magnetised by external field and used as the tool for polishing pre-machined surfaces. Another approach is to have magnetic abrasive particles, specially made for this purpose. In case of semi magnetic abrasive machining, abrasive grains such as Al2O3 and SiC possessing certain magnetic properties are directly magnetised by external magnetic field and are used as polishing tool. These abrasive particles are coated with iron particles when they are milled and hence exhibit magnetic properties. Keywords: Semi Magnetic Abrasive Machining INTRODUCTION Surface finish has a vital influence on important functional properties such as wear resistance and power losses due to friction on most of the engineering components. Poor surface finish will lead to the rupture of oil films on the peaks of the micro irregularities, which lead to a state approaching dry friction, and results in excessive wear of the contacting surfaces. Therefore fine finishing processes are employed in machining the surface of many critical machined components to obtain a very high surface finish apart form high dimensional accuracies. Such processes include grinding, lapping and super finishing among the traditional methods and elastic emission machining, Ion beam machining, mechano-chemical polishing and magnetic abrasive machining among unconventional methods. Even though these processes are in use for various applications, each process had its limitations in producing the desired surface finish on the components. Some of them are discussed in the forth coming sections. In traditional mechanical surface finishing operation such as grinding, lapping and super finishin