In mold making, the rounded corners of quadrilateral mold can be made from different positions, not necessarily from the middle. The specific fillet position depends on the designer and manufacturing requirements. Generally speaking, the purpose of making fillet is to avoid sharp corners and improve the durability and safety of the mold.

The common method is to make fillet from the edge of quadrangular die and gradually bend the arc to the middle of the die. This method can ensure the strength and stability of the mold and is relatively simple in the manufacturing process.

However, different fillet manufacturing methods can also be selected according to specific needs and design requirements. For example, in some cases, it may be necessary to create a larger fillet in the middle area of the mold to increase the fineness of the product or solve specific manufacturing problems.

In a word, the fillet position of quadrilateral die is determined according to the specific needs and design requirements, and there is no fixed regulation.