Nano-Surface Generation Using Low-Pressure Super-Finishing With Fine Diamond Stones

The fixed-abrasive process has been attracting attention as an alternative to the abrasive-free process for finishing surfaces, by virtue of its capacity to improve formability and alleviate environmental problems. Here, we focus on a super-finishing method that uses fine diamond stones. Super-finishing was attempted using low-pressures (< 0.5 MPa) with diamond abrasives averaging less than 3 μm in diameter. We investigated the influence of super-finishing parameters on the surface finish under low-pressure conditions for borosilicate glass. The following conclusions were reached. (1) The surface finish decreased with decreasing stone pressure for ductile cutting. By using a stone pressure of 0.1 MPa, a surface finish of 2 nm Ra with the #12,000 grindstone (mean grain diameter of 0.25 μm) was obtained. (2) Decreasing the mean grain diameter of the abrasive grains decreased the surface finish and could reduce crack formation. (3) A finer surface finish was obtained by increasing the volumetric grain percentage of the grindstone. (4) The maximum crossing angle minimally influenced the surface finish under low-pressure conditions. (5) We found the parameter groove aspect ratio and a method to reduce swell-out height. (6) We successfully demonstrated an evaluation method for polished surfaces and the cutting types. (7) Cracks are reduced on finished surfaces by keeping the depth of cut to less than 100 nm in the case of borosilicate glass.