The optimization project had a clear objective now: to reduce the reoxidation inclusion. Possible design modifications and constraints were discussed and finally there were 3 different modifications allowed to be implemented: the usage of chill, different runner design as well as additional machining allowance. See Pic 2: Different Version which was given by the foundry.
The chill was added to reduce the centreline shrinkage or also known as microporosity which was also present even though it was not the reason for the quality issue. Both the runner modifications and additional machining allowance were the changes intended to eliminate the reoxidation issue.
Instead of calculating the 3 new versions, a virtual Design of Experiment was prepared using MAGMASOFT® autonomous engineering technology. Total 8 different designs were created based on the combination of the 3 above variables. Even though there were more designs to be calculated for a virtual DoE, there was one significant advantage to proceed with this method: to determine the relationship between the variables (input) and the casting defect (objective). In other words, it is used to find cause-and-effect relationships. As for the objectives for this virtual DoE were the reoxidation inclusion (Inclusion Area), the turbulent during filling (Smooth Filling) and the centreline shrinkage (Microporosity).