| 摘要 |
PROBLEM TO BE SOLVED: To keep and improve the flatness and smoothness of a substrate for a magnetic recording medium without breaking a process by reversing the rotating directions of an upper lapping machine and a lower lapping machine every time working a designated number of times is ended. SOLUTION: A simultaneously both-sided working machine is so constructed that an upper lapping machine and a lower lapping machine 5 are rotated in the opposite directions. For example, the upper lapping machine is rotated clockwise, the lower lapping machine 5 is rotated counterclockwise, and a carrier 2, a sun gear 3 and an internal gear 4 are also rotated counterclockwise. The fine grinding condition is that the working pressure, the working time and the rotating speeds of the upper lapping machine and the lower lapping machine 5 are all designated values. The rotating speeds of the upper and lower lapping machines are reversed every time working is performed five times. The polishing condition is that the working pressure, the working time and the rotating speeds of the upper lapping machine and the lower lapping machine 5 are all designated values. The rotating speeds of the upper and lower lapping machines are reversed every time working is performed five times. Thus, the flatness and surface roughness of a worked article can be kept and improved. |
