PURPOSE: To control the plate thickness accurately and stably, and improve the yield of products by measuring the initial plate thickness of a disc to be ground, and computing the target grinding quantity on the basis of the initial plate thickness, and stopping a grinding device when the grinding quantity achieves the target grinding quantity.
CONSTITUTION: A grinding device pinches a disc with a carry between a pair of grinding surface plates, which rotate in the directions opposite to each other, to pressurize them, and the carry is epicycle-rotated to grind the disc. In this case, the displacement quantity, which is detected by a displacement quantity detecting unit 7 of the grinding surface plates positioned in the upper, and the existence of the rotation, which is detected by a rotation sensor 90 of the fixed grinder positioned in the lower, are input to a control means 8. The target grinding quantity of the disc to be ground is computed by a computing means 80 on the basis of the initial plate thickness of the disc to be ground. The required standard data is inputted by an input means 9. Furthermore, a result of the computing is displayed by a display means 81, and on the other hand, the upper and the lower grinding surface plates, a driving motor 4 and an elevation driving device 35 are controlled in response to the target grinding quantity.
YAMADA SATORU
TODE HIDEKI
