Vacuum casting consists in producing polyurethane (PU) parts in small-to-medium series with the following steps :
- Preparation of the master model that will be reproduced,
- Design and manufacturing of the silicon mold,
- Production of parts through a chemical process under vacuum : a reaction between isocyanate and polyols produces PU,
- Stripping and deburring of produced parts,
- Improvement of their surface finish.
Silicon molds are relatively inexpensive and quick to produce, while PU can take on many different properties such as flexibility gradation, mass colorization and flame retardant. The wear and tear of silicon molds limits this technology’s cost-effectiveness to small-and-medium series production.