HM-420/520 box Edge folding machine (for bottom-locked box ) is folding and forming machines for surface paper of upper and lower boxes. Pressure nozzles are used to bend the extruding parts of the surface paper into the boxes. These machines are equipped with devices such as pedal switches and magic eye switches, capable of adjusting the length and height of pressure nozzles according to the size of the boxes, and these machines function as quick speeds, high product quality and simple and quick operation, etc.