Load capacity of gears could be remarkably improved by making their tooth surface roughness smaller than 1μm Ry. In order to produce such gears, the authors developed a precision CNC gear grinding machine of the forming type. The shortcomings in using the above grinding machine was that the productivity of grinding with a conventional wheel was low, and the layer below the ground surface was occasionally damaged by a residual tensile stress.
Consequently, to supplement the precision grinding process, the authors also developed a microtruing machine which creates a high accuracy profile and a uniform grain height of the electroplated cBN grinding wheel.
The machine realized an axial stiffness of 300N / μm on the wheel spindle, and a positioning accuracy of about 50 ran. A conventional wheel was microtrued on the microtruing machine and tested for grinding a gear. The gear profile error, was 1 μm.