Mass production of LSR parts uses specialized injection molding machines that meter, mix and inject LSR into a heated mold. Due to the time and expense of this process, low-volume production and prototyping is often done with manual casting methods that use molds made of modeling board, RTV rubber or soft metal. However, although they are easier, faster and cheaper to produce, prototype molds have their own challenges. Making LSR parts with RTV molds is a multi-stage process requiring time and labor to produce the patterns and molds. Care is also needed to ensure the soft rubber RTV mold does not deform or stick to LSR parts. Machined molds overcome these challenges, but they can be much more expensive, time-consuming and labor intensive than RTV molds. Additionally, machining may have limitations with respect to the complexity of a part’s design.