These round ground posts are used to support the plate above the ejector housing. The functions of support pillars are to help prevent the plate deflection caused by injection molding pressure. Without this support along with thickness of the support plate the mold can bow under injection pressure and cause flash. When a mold has had some use the support pillars will hob into the plates and lose their effectiveness. As a result this usually shows up as flash in the center of the mold. They normally have a .002-inch preload to them to ensure that the support plate will not flex during use. They are most effective when placed in the center of the mold. Support Plate- This plate used to keep the core plate from deflecting during injection. This plate is usually the thickest plate in the mold base, because it has to keep the mold from flexing during injection. The unsupported side of the plate has the ejector plates space underneath it and can easily deflect if there is not enough thickness. It also provides a base for the cores to sit on and provides space to feed the water lines to the cores.