The process of shell molding or “croning” consists in placing a sand mixed with a thermoplastic resin and a catalyst. The mixture is then put in contact with a tooling heated between 200 and 300°C giving a mold having the shape of the part. The molten steel is then poured inside to produce the final part. This process is used by Saint Jean Industries Laval to produce cast iron and steel parts. It allows to obtain an excellent surface finish and a precision incomparable to other processes using sand.
The most precise process using sand: it is possible to reach dimensional tolerances of +/- 0.1 mm and draft of 0.5° locally
Obtaining raw parts close to the final shape, hence less machining and weight reduction
Locally thin parts: 2.5 +/- 0.5 mm, thanks to the excellent surface finish of the shells
Wide choice of materials
Modular and flexible production equipment, suitable for medium and large series
Thin shells and therefore less sand to recycle.