One is: the content of impurities in the molten iron, especially the content of iron oxide, it is very easy to produce slag or slag pores on the surface of the machine tool castings;

The second is: the gas content in molten iron, high gas content is easy to make large castings have pores on the surface or under the skin. The main measures we take are to raise the temperature of the molten iron and establish a perfect cupola inspection system to ensure that the cupola is in a normal state.

The choice of process parameters The process parameters have a greater impact on the dimensional accuracy and contour definition of large machine tools. After many process tests, each process parameter was carefully selected.