What does "thermal stability" in the context of sand molds refer to?

In the context of sand molds, "thermal stability" refers to the ability of the mold to maintain its shape and structural integrity when exposed to high temperatures during the metal casting process. When molten metal is poured into a sand mold, the mold must resist deformation, melting, or breakdown caused by the heat. If the mold cannot maintain its shape, it can lead to defects in the casted part, such as dimensional inaccuracies or surface imperfections. Essentially, thermal stability is crucial for ensuring that the final product aligns with the desired specifications and quality.

Other options do not accurately capture the concept of thermal stability. The speed at which a mold can be reused relates to manufacturing efficiency but does not pertain to the mold's ability to withstand heat. The resilience of sand to changes in temperature, while relevant, is more about thermal properties than the mold's capacity to retain its form. The ratio of sand to plaster in the mixture is a compositional aspect that influences various properties of the mold but does not define thermal stability.