The forming material of the sand core had a great progress. Now,resin cores are commonly used in china sand casting industry. The yellow appearance is its typical feature. Resin sand can be made out by blending fine sand and resin with certain proportion. Different proportion can lead to different shrinkage rate of the sand core. And the resin sand core is subject to absorbing moisture. The damping sand core will affect the dimension and the surface quality of the casting part. So a special dry place should be arranged for storage of resin sand cores.