The interior of some castings can in combination with casting technology only be produced with sand cores. Some products have complex shapes that demand the entire core to be assembled from several smaller ones. Sand core, produced according to the ColdBox procedure, is used to make hollow castings, which are produced using gravity tilt casting or low pressure die casting.
The line for core production consists of:
- two silos for quartz sand,
- a system for sand and daily silo transport,
- a mixer to prepare a mixure of sand and binder,
- a system to transport the mixture to the core machine,
- machines for core production Laempe Mössner Sinto Typ L20, Typ L40, Typ L65.
- ammonia fume precipitation.
The basic raw material used for core production is quartz sand. The following additives are used in the core production:
- binder for sand (ecological polyurethane resin),
- catalyst, which consolidates the shaped structure (triethylamine).
After production cores must dry, thus they are stored in a separate storage for 24h. The air in the storage is heated and circulated to ensure constant conditions (temperature, humidity).