| 摘要 |
PROBLEM TO BE SOLVED: To keep and improve the flatness, surface roughness, appearance and dimensional accuracy of polishing by reversing the rotating direction of a carrier after the end of polishing designated number of times. SOLUTION: In case of seeing a simultaneously both-sided polishing machine from above, a sun gear 3, an internal gear 4 and a lower lapping machine 5 are all rotated counterclockwise, an upper lapping machine is rotated clockwise, and a carrier 2 is revolved round the sun gear 3 counterclockwise. The rotating direction of the carrier 2 is reversed every time working is performed five times. Concerning the cycle of reversion in the rotating direction of the carrier, it is suitable that the number of times of conducting a polishing process is within 10 times, and preferably it is within 5 times. Thus, the rotating direction of the carrier 2 is reversed every time polishing is performed a designated number of times, whereby the flatness and surface roughness of a product can be kept and improved. Further a magnetic head can be decreased in floating amount, so that the magnetic disc can be densificated and especially the line recording density can be improved. |
