由于水玻璃自硬砂有时间性的限制,而在制型及制芯工艺中,例如起模、翻型、吊芯等操作过程中,又不可避免的会发生损坏和破裂等情况,对于自硬砂型的修补,一般是比较困难的。过去都是采用水玻璃作粘结剂,或者用粘土砂修补,往往由于硬化慢,强度差,产 Due to the time constraints of water glass self-hardening sand, and in the system and core making process, such as the mold, turning, hanging core and other operations, but also inevitably occur damage and rupture, etc. For Hard sand-type repair, is generally more difficult. In the past are using water glass as a binder, or clay sand repair, often due to slow hardening, poor strength, production