Magnetorheological Ball End Finishing Process

Finishing of three-dimensional (3D) surfaces such as grooves, projections, or complex in depth profiles on workpiece surfaces is a challenging task for the many existing advanced fine finishing processes. The advanced fine finishing processes have been developed to precisely control the abrading forces through external magnetic field. The applications of state-of-art finishing processes are limited to specific geometries only such as concave, convex, flat, and aspherical shapes due to restriction on relative movement of finishing medium and workpiece. Many of these processes are incapable of finishing of 3D intricate shaped surfaces. To overcome this problem, a new finishing process for flat as well as 3D surfaces using ball-end magnetorheological (MR) finishing tool is developed for ferromagnetic as well as non-ferromagnetic materials. The smart behavior of MRP fluid is utilized to precisely control the finishing forces and hence the final surface finish. A computer controlled experimental setup is designed and developed to study the process characteristics and performance. The magnetostatic simulations of flux density in MRP fluid between tool and workpiece has been done to visualize the finishing spot shape and size in contact with the workpiece surface. EN31 magnetic steel and nonmagnetic copper workpieces were finished using developed machine to validate the process concept.