Dressing technology of arc diamond wheel by roll abrading in aspheric parallel grinding

In order to dress arc diamond wheel in aspheric parallel grinding efficiently and precisely, a novel truing technique by roll abrading with silicon carbide wheel was proposed. The rotary axis of diamond wheel and dressing wheel were orthogonal. Based on X/Y/Z three-axis linkage controlling, the diamond wheel moved around the outer cylindrical surface of the dressing wheel. In this process the dressing wheel abraded the surface of arc diamond wheel. After analysis of geometric relationship between diamond wheel and dressing wheel, the mathematical model of motion trajectory during the truing process was established. And the dressing efficiency and accuracy were analyzed theoretically. The width of dressing wheel was a key parameter affecting the precision of diamond wheel and dressing efficiency. Then, experiments of truing a type of resin-bonded arc diamond wheel were carried out. The arc error, radial runout error, and radius fluctuation decreased from about 110 μm, 290 μm, and 10 mm to 4 μm, 1.5 μm, and 0.2 mm respectively by the dressing process within 7 h. And the abrasive grains on the surface of diamond wheel had a better cutting edge. At the end, a large-scale aspheric lens was machined by this diamond wheel. The P-V of form error was below 4 μm. All the experiments verified that this new approach was feasible, and this truing technique had been applied in ultra-precision grinding of large-aperture aspheric lens, which improved the overall processing efficiency.