Vent

These are small air passages between the parting lines of steel components that allow the gases to pass out of the mold. They are usually located at the end of fill. They have to be large enough to let the air and gas out yet small enough to retain the plastic without flashing. Vents near the gates are more likely to flash and are usually smaller as they have molten material near them. The flash point of Crystalline material is smaller than that of the amorphous materials. True crystalline material will flash in spaces of .0127 mm (.0005 in) while some amorphous materials will not flash at .0381 mm (.0015 in).