Urethane casting, often called Vacuum Casting, is a manufacturing process used for rapid prototyping and low production runs. The urethane casting process involves pouring liquid urethane material into a silicone mold, followed by curing in an oven, and then removing the plastic part from the mold once it has cooled. Secondary operations commonly used in production settings can also be performed on the cast parts if desired. Urethane casting is ideal for low-volume part runs and prototypes. The silicone molds do not last long and will typically only cast about 20 parts. The silicone mold is easy and relatively inexpensive to make, giving urethane casting a unique advantage over other plastic part manufacturing processes like production injection molding in low volume scenarios.