Theoretical and experimental study of ceramic balls lapping with eccentric plates and eccentric V-groove

Ceramic balls are produced via powder metallurgy and compared to steel balls are preferred due to their special physical and mechanical properties. Ceramic balls can reach the desired surface finishing, sphericity, and diameter by finishing processes such as grinding, lapping, and polishing. By considering the length of time and high costs of the finishing process, creating an economic mechanism is of great importance in the use of ceramic balls. The present paper was conducted to investigate the eccentric lapping plates mechanism with eccentric V-grooves for ceramic balls lapping. This mechanism is proposed to increase the material removal rate (MRR) and to reduce the sphericity error of the ceramic balls. The effects of parameters including lower and upper lapping plate rotation speeds, the eccentricity of lapping plates, and lapping force were investigated on MRR, and the reduction of sphericity error. The kinematic analysis was performed to calculate the trajectory length and its distribution on the ball surface. Experimental tests were carried out to validate the kinematic analysis on the pre-sintered Al2O3 balls. The effects of the above-mentioned parameters on the lapping process were determined. The proposed mechanism provided an MRR of 0.766 mm/h; in this regard, sphericity error also reduced down 0.184 mm in 20 min.