In the work there are considered the manufacturing stages of the casting of frame of the terminal box in the conditions of JSC "Vladimir electromotive plant". On the basis of the performed computer simulation of the casting process of the casting in the sand mould there were obtained the three-dimensional fields of cooling, the flow velocities and the Niyama criterion for gray cast iron. The time of cooling (solidification) of the alloy in the sand mould was determined. In accordance with the basic technological process of casting in the sand mould, the comparison of the admissible value of volumetric shrinkage of the casting material with the calculated value was performed.