Multi directional plastic geogrids are punched on polymer sheets (mostly made of polypropylene or G-

Multi directional plastic geogrids are punched on polymer sheets (mostly made of polypropylene or G-density polyethylene) that have been extruded, and then subjected to directional stretching under heating conditions. The unidirectional stretching grid is made by stretching only along the length direction of the board; The bi-directional stretching grid is made by continuing to stretch the unidirectional stretching grid in the direction perpendicular to its length.