Polishing mechanical arm capable of rapidly detaching and replacing polishing disc

The polishing mechanical arm comprises a fixing plate, an air compressor and a robot control cabinet are fixedly connected to the upper surface of the fixing plate, a fixing frame is fixedly connected to the upper surface of the fixing plate, a polishing machine is fixedly connected to the upper surface of the fixing frame, and a polishing disc is fixedly connected to the polishing machine. The upper surface of the fixing frame is fixedly connected with a conveying unit, and the upper surface of the fixing plate is fixedly connected with a mechanical arm. According to the device, through cooperation of the air compressor and the conveying unit, the effect that the air compressor pushes the gas cutter to push materials to the conveying unit is achieved, the effect of detecting the arrival of the materials is achieved through a first photoelectric sensor and a second photoelectric sensor at the conveying unit, and the purpose that the conveying unit stops conveying is achieved; and through cooperation of the me