This is a precision process produced by pouring molten aluminum into CNC machined steel molds under gravity, centrifugal force, or low pressure. Due to the rapid heat transfer from the molten aluminum to the mold itself, the castings have finer grain structures and better strength properties than casts made by Sand Casting method. Permanent Mold aluminum casting permits casting designs with thinner walls and less weight. Permanent mold castings are less subject to shrinkage and gas porosity than Sand Castings and do not contain the entrapped gas often found in Die Castings.