CO2水玻璃砂出砂性能很差，用于制芯时，对形状复杂的砂芯出砂就特别困难，因此常常对不易出砂的砂芯用树脂砂制作。但树脂砂成本很高，是CO2水玻璃砂的12倍左右。为了降低成本，减少树脂砂的用量，我厂从生产实践中总结出，对一些复杂的砂芯采用两种砂复合制芯的方法。即在容 CO2 water glass sand sand performance is poor, when used in the system core, the shape of the sand core sand production is particularly difficult, it is often difficult to sand core resin sand production. However, the cost of resin sand is high, about 12 times that of CO2 water glass sand. In order to reduce costs and reduce the amount of resin sand, our factory concluded from the production practice, for some complex sand core using two sand composite core method. In the capacity