First of all, sorry we late because we need to confirm quality after improved.
According to casting condition after meeting when you arrived in KAT , from your suggest about upper air cooling
after that the condition changed .Now we already done with leak solving problem after produced 1 month leak
reject down around 50% especially (640A-17 ,A7) and next target we hope to 0% .
Finally thank you for you suggest and we will follow continuously and extend results to new model standard.
from casting theory ( Temperature range Lower/Side/Upper /cooling condition /die coat /mold shape design).
We will find best condition for up productivity.