Research on the Influence of the Diamond Wheel Wears on Machining Accuracy During Large Depth-to-diameter Ratio Ultra-precision Aspheric Grinding Process

During grinding large depth-to-diameter ratio aspheric surface part of high precision and high quality, the wearing of the diamond wheel would affect the machining accuracy of the aspheric surface part greatly. The influences of the wearing of the diamond wheel on machining accuracy of large depth-to-diameter ratio aspheric surface part are analyzed theoretically in this paper. The ultra-precision aspheric grinding system is researched out. In this system, the shape of the diamond wheel is ball-headed, and on-position dressing mechanism of the discharge principle is designed. After dressing, the profile accuracy of the ball-headed diamond wheel is very high, its diameter error is less than 0.1 μm, and the micro-blade group on the same height of the ball-headed diamond wheel is very well, it could be dressed directly without tearing down the workpiece when the diamond wheel is blunt. After dressing, this ball-headed diamond wheel could machine the aspheric workpiece directly. It resolved the problem that the assembling and wearing of the ball-headed diamond wheel affected the machining accuracy greatly. Finally, lots of grinding experiments are carried out on the grinding system. Grinding results show that profiles accuracy was 0.3 μm and the surface roughness is less than 0.01 μm.