铸钢件冷型或专箱刮砂是一种新的造型工艺,亦有称之谓“挂砂”或“衬砂”。毛主席指出;“人的正确思想是从那里来的?是从天上掉下来的吗?不是。是自己头脑里固有的吗?不是。人的正确思想,只能从社会实践中来,只能从社会的生产斗争、阶级斗 Cast steel cold or special box to blow sand is a new modeling process, also known as “hanging sand” or “lining sand.” Chairman Mao pointed out: "From where is the correct thought of a man come from? Has it fallen from heaven? No. Is it inherent in his mind? Not a man’s correct thought can only come from social practice, From the social production struggle, class struggle