It became always more important in Cast Iron Foundry to have a process control system that helps to reduce the variability and follow the correct specifications, to simplify the detection of eventual inoculation problems or incorrect working ranges.In the thesis, it is presented a case study of a specific defect of microporosity that appeared in the internal areas of some castings. The presence of the defect arose gradually over a certain period and the Foundry tried to counteract it by changing the feeding system, increasing the size of risers, or increasing the amount of inoculant, but anyone of these expensive measures solved the problem: at the opposite sometimes, it intensified the defect.The approach used in this work consists of a first analysis of the process variables related to the foundry process, with particular attention to the thermal analysis, followed by a proposal of performing some trials by reducing the variability in the process, pointing to the correct carbon equivalent target and, dosing the correct amount of inoculant addition.The obtained improvements demonstrated the big responsibility of the variance and the inoculation level in excess in the casting process.