Magnetic abrasive finishing was first mentioned by Coats in a patent filed in 1938 [COAT40, SINL10]. It is a finishing method for flat, cylindrical, and ball grinding and especially suited for hard to machine materials [SINL10]. The magnetic abrasive particles can be produced by sintering, adhesive based processes, plasma based process (powder melting or plasma spraying), mixing (loose bonding), or other methods [SINL10]. Sing et al. [SINL10] summarize exisiting production methods.
Magnetorheological abrasive flow finishing is one variant that works with magnetorheological effects exhibited by carbonyl iron particles along with abrasive particles in a non-magnetic base viscoplastic medium [JHA06]. Magneto-abrasive machining is used to prepare defined cutting edges at HSS drills so that the run-in phase of the drill can be avoided and tool life is increased [KARP09].
9.2.2.7 Vortex Machining
Vortex machining is a new abrasive process for nano applications and works with vortices that are caused by an oscillating fiber in colloidal abrasive slurry [HOWA12]. The fiber is close to the workpiece surface (about 20 pm), but does not touch it. The resulting material removal footprints have micrometer sized lateral dimensions and nanometer depths [HOWA12].