In gravity die casting molten aluminium is poured into a metallic tool. The casting temperature is about 750°C. The tolerances and surface finish are good. The use of sand cores in gravity die casting enables casting of very complex components. Gravity die casting method is competitive casting method when production quantity is relatively small or when heat treatment is needed to improve the mechanical properties. This casting method gives better tolerances and surface finish than sand casting. The tooling costs are somewhat higher than by sand casting. Using sand cores in gravity die casting makes it possible to manufacture items with complicated inner shapes in a cost effective way in small and medium quantities. Typical products produced this way are e.g. air intake components for diesel engines, valves for flow systems, tanks for air conditioning systems etc. Typically they have curved inner shapes which are optimized for gas or liquid flow. Using shell sand cores gives close tolerances and relatively good surface quality also for the surfaces solidifying against the sand core.