Semi-centrifugal casting and Centrifuging
Semi-centrifugal casting China CNC machining is used for jobs, which are more complicated than those possible in true centrifugal casting, but are axisymmetric in nature. It is not necessary that these should have a central hole, which is to be obtained with the help of a core. The moulds made of sand or metal are rotated about a vertical axis and the metal enters the mould through the central pouring basin as in Fig. 11.13. For larger production rates, the moulds can be stacked one over the other, China CNC machining all feeding from the same central pouring basin. The rotating speeds used in this process are not as high as in the case of true centrifugal casting.
In order to obtain higher metal pressures during solidification, when casting shape is not axisymmetrical, the centrifuging process is used. This is suitable only for small jobs of any shape. A number of such small jobs are joined together by means of radial runners with a central sprue on a revolving table as in Fig. 11.14. The jobs are uniformly placed on the table around the periphery so that their masses are properly balanced. China CNC machining The process is similar to semi-centrifugal casting.