| 摘要 |
PURPOSE:To make it possible to perform grinding to a surface having uniform roughness by stopping feeding when grindding stone feeding reaches the set point and by reducing the number of table turning caused by force of inertia by stopping the power supply to a motor in spark out grinding. CONSTITUTION:In grinding with a grinding stone 3 fed to a wafer 2, when a spindle head 11 is lowered feeding the grinding stone 3 to the specified position, since the output of an amplifier 17 corresponds to that of a feeding position setting circuit 18, the signals from a comparator 19 are charged to control circuits 24 and 25, the circuit 24 stopping a motor 14 to stop the feeding. On the other hand, the circuit 25 stops the power supply to a motor 6 leaving a table 1 turning being caused by force of inertia to perform the spark out grinding of the wafer 2, and the turn of the table 1 is transmitted to the motor 6 is, therefore, reduced with reducing the number of turns of the table 1. The number of revolutions is converted to a feed rate by a circuit 21 and the result is compared with the output of a circuit 22. If it meets the output, the control circuit 24 outputs signals to raise the spindle head completing grinding. This provides a surface having uniform roughness.
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