MAGNETIC ABRASIVE FINISHING OF MAGNESIUM ALLOY USING ELECTROMAGNET

Abstract

The world moves towards those materials which have better mechanical properties like high hardness, high strength to weight ratio, toughness and better microstructUre etc. and which are easier to process. With the advancement in the field of materials, the finishing processes have also become more and more challenging. The conventional finishing processes like grinding, lapping, and honing cannot be applied economically. MAF process is an advanced finishing process which is used for finishing of advance engineering materials. With the help of this process, internal as well as external area can be finished. A lot of work has been done on ferrous material using Magnetic abrasive finishing, but relatively less work has been done on nonferrous materials. Recently, research work on magnesium alloy has rapidly increased due to its better properties and variety of industrial applications. Industries are ftcusing on reducing weight and - volume of material, therefore magnesium alloy, which is the lightest structural material and also has lot of applications, was chosen for study. Magnetic assisted process is useful for super finishing, dehurring, polishing, cleaning of ferrous as well as nonferrous alloy. In MAF process the surface of the workpieCe (AZ91) is finished by removing microchips using abrasive particles. The abrasive particle orks as a cutting tool in presence of magnetic field. In the present study, an electro magnet is used which generates magnetic field in between the gap of work piece and electromagnet pole. The use of electromagnet facilitates variable magnetic fields, to have a better control on forces during the finishing process. Permanent magnet is used on the other side of the magnesium plate in order to improve the rigidity of the flexible magnetic abrasive brush. In this work. the effect of process parameters - working gap, current and rotational speed is studied on the response parameters - Percentage change in surface roughness (%ARa), normal force (Fn) and finishing torque(Mz). It has been revealed that working gap and current are significant process parameters.