Nano-Mirror Surface Generation for Hardened Steel Using Ultra-Low Pressure Super-Finishing

Abstract

The fixed-abrasive process has attracted significant attention as an alternative to the loose-abrasive process for the final finishing of precision parts due to the improvement in shaping capability, processing efficiency, and environmental friendliness. Here, a new super-finishing method is proposed that involves fine super-abrasive stones (having a mean grain diameter of 8 μm or less) and ultra-low pressure (<0.1 MPa). The proposed method was implemented using a prototype super-finishing machine which was previously fabricated by the authors. Influences of lower stone pressure and finer abrasive grains on the surface roughness of SUJ2 (JIS) hardened steel were investigated. The following conclusions were obtained: (1) It was confirmed that super-finishing with a processing pressure of 0.02 MPa could be achieved using a fine-grit cBN stone. (2) Approximately half the surface roughness value of that achieved under conventional conditions could be obtained using ultra-low pressure. (3) The surface generation model, which was proposed based on plastic and elastic deformation, provided good agreement with the experimental results.