Cartesian palletizers are machines that pick up few cases at the time, not the full layer. The layer is completed in multiple movement of the machine. The control system of the machine stores all the coordinates of the pick and release positions. The cases can be picked with pliers or with vacuum. Pliers assure a more firm pick, but with the drawback that the thickness of the plier can leave a small space between the packs, mainly in the last release of the layer. Vacuum picking system, on the contrary allow a very compact layer, but the pickup surface has to be flat enough in order to guarantee a safe product picking