As for green sand cast, heated sand always results in higher scrap rate, more bentonite cost, and multiple defects: sand inclusion, roughness defect, pinhole, pores, succulent and damage due to the moisture loss of sand mould.

According to actual experiment in iron foundry, the sand temperature fluctuates between 32℃～193℃ as shown in fig 3. So how to correctly cool down the sand and reduce lost? The keys are shown below.

After shakeout, cooling system should mix evenly the sand at different temperatures in an appropriate manner. Due to homogenization effect, system sand temperature will gradually change over time without sudden changes. To achieve effectively cool down, contact time of water and all sand particles must be sufficient. Meanwhile, efforts must be made to remove the moisture by vaporize.

To vaporize the hot sand, water must be added by appropriate amount, which means the moisture content should be strictly controlled according to the need of molding. In addition, the adding of bentonite in sand cooling system is beneficial for improving efficiency.

Strictly controlling the moisture and sand uniformity of the system plays a positive role in ensuring the uniformity of the spare sand delivered to the molding process. Before mixing sand, it is necessary to effectively mix and control the temperature and moisture of the falling sand, which can increase the capacity of the compaction control device on the production line.