Shell Moulding

This fusion system can be described as follows:

the sand that is covered by a thin (3-6%) thermosetting phenolic resin and a liquid catalyst, is discharged, burned, and shot on a hot model. The pattern is usually made of cast iron and is heated between 230 °C and 315 °C (450-600 °F).

The sand is discharged on the model; here begins the first phase in which the thermosetting present in the resin, in contact with the hot model, begins to harden. At this point, the model is rotated by 360° so that the sand in excess is dropped and, depending on the sand thickness that is put on the model, is burned for a certain time. The result is the formation of two shells, which are extracted from the model with the help of some ejectors.

Afterwards, the two shells are combined by gluing, using a thermosetting adhesive, to form a mould; the finished mould can then be used immediately or can be stored for an indefinite time period.