Stocker is the main cassette transfer equipment of TFT-LCD industry. Breakdown of stocker causes a serious production problem by stopping cassette transfer. Therefore, Prevention of breakdown of stocker is crucial factor of yield. The main problem is ...
Stocker is the main cassette transfer equipment of TFT-LCD industry. Breakdown of stocker causes a serious production problem by stopping cassette transfer. Therefore, Prevention of breakdown of stocker is crucial factor of yield. The main problem is failure of servo motor which driving stocker. Acceleration vibrograph sensor, which uses piezoelectric effect, is commonly used to analysis problem of servo motor. However, high cost is the wall to adapt acceleration vibrograph sensor. Therefore, this paper proposes a load factor based preliminary failure detection method. We adapt two algorithm, set point and SPC-mixture, to check problem of servo motor. Our novel method effectively detects servo motor problem of stocker.