MAGNETIC FLUID GRINDING OF HIP-SI3N4 ROLLERS

Hot pressed silicon nitride (Si3N4) rollers were finished by magnetic fluid grinding yielding a surface finish, R(a) of about 5 nm. Three ty pes of abrasives (B4C, SiC, and Cr2O3) in the 30 to 50 mu m size range and three grain sizes of one of the abrasives, namely, Cr2O3 (3, 6, a nd 30 mu m) were used to investigate the effect of abrasive and grain size on the removal rates and surface finish. High removal rate (1.1 m u m min(-1)) was obtained with B4C abrasive and high surface finish (R (a) of 5 nm) with Cr2O3 abrasive. Magnetic fluid grinding process enab les finishing of the rollers with rounded edges (crowns) which may be ideal for roller bearing applications.