POLYBAG GRIPPING SUCTION CUP

A vacuum cup connected to a robotic arm for picking and placing items is disclosed. The vacuum cup includes one or more walls that defines (i) a first internal cavity and (ii) an opening to the first internal cavity, wherein the first internal cavity is defined at least in part by an interior surface adjacent to the opening to the first internal cavity, the interior surface defining an internal ridge positioned to mechanically engage a material drawn into the first internal cavity through the opening at an angle such that the mechanical engagement resists the material being removed from the first internal cavity via the opening. In response to the item being engaged and the suction system controlling the pressure within the first internal cavity to create a vacuum seal between the vacuum cup and the item, at least part of the item is caused to enter the first internal cavity at least during engagement of the vacuum seal.