Magnetic fluid grinding of HIP-Si3N4 rollers

Hot pressed silicon nitride (Si3N4) rollers were finished by magnetic fluid grinding yielding a surface finish, Ra of about 5 nm. Three types of abrasives (B4C, SiC, and Cr203) in the 30 to 50 μm size range and three grain sizes of one of the abrasives, namely, Cr203 (3, 6, and 30 μm) were used to investigate the effect of abrasive and grain size on the removal rates and surface finish. High removal rate (1.1μm min−1) was obtained with B4C abrasive and high surface finish (Ra of 5 nm) with Cr203 abrasive. Magnetic fluid grinding process enables finishing of the rollers with rounded edges (crowns) which may be ideal for roller bearing applications.