A mold core is a component used in the casting process to create hollow sections or internal features in a cast part. It is typically made from materials like sand, metal, or ceramic and is placed inside a mold before the molten material is poured. The core shapes the interior of the final product, allowing for complex designs that would be difficult to achieve with solid casting. After the casting process, the mold core is removed, leaving behind the desired cavity. This technique is commonly used in manufacturing parts for industries such as automotive and aerospace, where precision and functionality are crucial.