Machining device for metal plate large fillet and machining method of machining device

The invention relates to the technical field of metal plate large fillet machining, in particular to a metal plate large fillet machining device and a machining method thereof.The metal plate large fillet machining device comprises a fixing frame, a mounting frame, a supporting plate, a first motor and a polishing frame, a second motor is fixedly mounted on the upper surface of the polishing frame, and a rotating shaft is fixedly connected to a rotating shaft of the second motor; according to the metal plate polishing device, the locking block assembly is arranged, when the rotating frame and the polishing frame drive the L-shaped frame to move to the intersection of the large fillet and the right-angle side of a metal plate, the pull-back mechanism controls the locking block assembly to unlock the rotating frame, then the second air cylinder is started, the rotating frame is driven to rotate, and the rotating frame is driven to rotate; and the second air cylinder pulls the rotating frame and the grinding fra