Oscillating-plate shaping method for ceramic ball blanks

Abstract

To improve the shaping efficiency and the accuracy of ceramic ball blanks, an oscillating-plate shaping method was developed. In the new shaping process, the ceramic ball blanks were pre-sintered to obtain enough strength to resist the crushing force, and then processed by the oscillating-plate shaping method. Owing to the improvements of sphericity and the size consistency of blanks, the efficiency of the followed lapping process for the fully sintered ceramic balls will be enhanced significantly. The motion of ball blank in the shaping process was investigated through kinematic simulation based on ADAMS model. Shaping experiments of Ø13 mm pre-sintered Si₃N₄ ceramic ball blanks were carried out. The average diameter of ball blank decreased from 13.097 ± 0.092 mm (Avg. ± SD.) to 12.407 ± 0.007 mm, and the sphericity was improved from113.9 ± 42.7 to 4.5 ± 1.6 μm in 45-min shaping. The lapping experiments to reduce the sphericity error of shaped and unshaped ceramic balls after the full sintering to 1 μm were also carried out. It takes 55 h for the shaped blanks and 135 h for the unshaped blanks respectively. The results show that the oscillating-plate shaping is a promising method to improve the processing efficiency of ceramic balls significantly by the improvements of the sphericity and size consistency of the as-received ceramic ball blank.