PURPOSE: To make it possible to mirror-surface finish the outer surface of a disc with a satisfactory surface roughness, by changing the diameters of tools or the center positions of the tools so as to control the rotating torque of the disc produced by the tools rotating at a high speed.
CONSTITUTION: An aluminum thin disc 1 to be mirror-surface finished, is rotatably supported at its periphery by means of a plurality of rollers 2, and tools 3, 4 are pressed against both surfaces of the disc 1 so that the mirror- surface finishing is carried out. At this stage, the disc is rotated by the tools 3, 4 rotating at a high speed, so that a slight force applied to the rollers 2 is sufficient for pressing the disc. Further, the rotating torque and the rotational speed of the disc 1 is controlled by changing the diameters of the tools 3, 4 and the center positions of the tools 3, 4, and therefore, the mirror-surface finishing of the outer surface of the disc 1 may be carried out without deteriorating the flatness thereof. Thus, the disc 1 made of aluminum or alloy thereof, having been subjected to the mirror-surface finishing may be used as a recording medium disc for electronic apparatus.
KATSUMOTO KENICHI
MURAI HIDEO
MATSUSHITA TOMIHARU
MOTONISHI SUGURU
