Automatic punching device for metal shell

The utility model relates to an automatic metal shell punching device which comprises a frame body, a supporting plate and a limiting mechanism, and a punching mechanism is installed on the frame body; the supporting plate is arranged on the frame body and is opposite to the punching mechanism, a module is arranged on the supporting plate, a channel allowing a workpiece to penetrate through is formed in the module, and an open hole allowing the punching mechanism to punch is further formed in the module; the limiting mechanism comprises a mounting assembly and a limiting block, the limiting block is movably arranged on the mounting assembly and has a first position and a second position, when the limiting block is located at the first position, the limiting block extends into the hole of the workpiece to limit the workpiece to move in the first direction, and when the limiting block is located at the second position, the limiting block is located on the surface of the workpiece to limit the workpiece to move