On-machine precision truing of ultrathin arc-shaped diamond wheels for grinding aspherical microstructure arrays

Precision grinding with ultrathin arc-shaped diamond (UAD) grinding wheels provides a satisfactory solution for the fabrication of high-quality microstructures on tungsten carbide (WC) molds. However, ultrathin grinding wheels are difficult to be trued, due to the limited small grinding wheel profile. In this paper, an on-machine truing method for ultrathin arc-shaped diamond grinding wheels is proposed. First, a model of the three-axis linkage controlling truing for the diamond grinding wheel was introduced. Then, the effects of the setting and measurement errors of the grinding wheel on the profile radius were theoretically analyzed. A mathematical model of the error was developed. Furthermore, an aspherical microstructure array of tungsten carbide was ground by the trued diamond grinding wheel. The experimental results demonstrated that the expected arc radius of the grinding wheel could be achieved and the binderless tungsten carbide mold could be ground efficiently and precisely. The profile error of the grinding wheel (diameter of 23 mm, thickness of 0.38 mm) reached 8.5 μm. An aspherical microstructure array surface of tungsten carbide with a form accuracy of 15 μm was obtained by grinding with the trued diamond grinding wheel without additional compensation.