The process begins with the manufacturing of a wax pattern from a mold. The mold can be of various materials but it is usually constructed of aluminum. Aluminum is used because of its ability to transfer heat from warm wax injected into the mold cavity. The mold also must be able to withstand hydrostatic pressures from the wax being introduced without distorting. Investment cast parts do not require draft incorporated into the tooling. Complexity of shape is achieved with pull pieces in the tool forming cored areas, collapsible internal areas, use of ceramic cores and water soluble wax cores. The mold can range from a very simple design to be manually handled to a very complex part for automatic injection equipment with pneumatic draw pieces and internal cooling passages. The resulting pattern is a positive or looks like the desired part to be cast. The wax is also not a simple material but is specifically chosen to give consistent dimensional shrinkage, strength / ductility and low ash content.