The copper moulds are produced by machining the top of a copper block into anode shapes. These moulds are then used for the continuous casting of copper anodes, each weighing 300 kg. (The mould will weigh around 4000 kg). During the casting process, the mould surface develops cracks, which affect the smoothness of the copper anodes produced. How can this issue be resolved?

(PS Barium sulphate mixture is being used before each casting for releasing copper anode)