Abstract: An on-machine precision form truing of resin bonded arc shaped diamond wheels by green SiC grinding rod is proposed for precision grinding spherical, aspherical, free-form surfaces. The circular interpolation radius compensation method and GC grinding rod motion trajectory is designed based on geometric relationship between the GC grinding rod and wheel during the truing process. The truing performance is evaluated according to the data of arc wheel collected by KEYENCE micrometer. The truing accuracy and truing ratio (wheel and GC grinding rod volume wear ratio) are investigated with reference to the circular interpolation speed and depth of cut in between the different grain sized GC grinding rod and diamond wheels. The results show that the different radius arc shaped wheels could be trued by this on-machine truing method while the vertical direction position error of wheel could also be corrected after truing. In addition the high truing ratio is of 0.7~6.7 obtained in case of truing D3 & D7 diamond wheels by 400# &800# GC grinding rod. As compared to 400# &1500#, 800# GC grinding rod with grains of exhibits more suitability in truing D3 & D7 diamond wheels. The truing depth of cut shows the greater impact over circular interpolation speed, in generating more accurate arc radius and less shape error, featuring the decreased depth of cut resulting in improved arc radius accuracy. Through the proposed on machine precision truing technique, the D3 & D7 resin boned diamond wheels could be trued with arc radius errors less than 5 percent, while the arc profile errors could be reduced to under 3 μm /4 mm for D3 wheel and 6 μm /4 mm for D7 wheel respectively, which is about 14 times improvement over before truing.

Key words: arc radius, diamond wheel, GC grinding rod, precision form truing, shape error, truing ratio