Cardboard baler uses one or more metal plates and a hydraulic arm, 

pushing the plate down on cardboard with enormous pressure. 

Cardboard Bailer compacts the cardboard into a large, dense  rectangular or cube box which is typically held together by its own internal pressure. Then this bale is  tied with metal wire to secure it together and placed on a pallet which allows it to be moved through the use of a forklift or pallet jack.