What are the extensions of the flat side of a part beyond the radius of the bend called?

The extensions of the flat side of a part beyond the radius of the bend are known as mold lines. These lines are crucial in the context of forming and bending metal because they provide a reference for how far the flat material extends before the bend occurs. Proper understanding of mold lines is essential for achieving precise bends and ensuring that the final dimensions of the parts are accurate, especially in the aircraft metal structural repair industry where precision is key.

The term "mold line" specifically refers to this conceptual boundary that indicates where the flat material begins to transition into the bend. This differs from other concepts such as bend lines, which indicate the actual line where the bending takes place. Flange extensions refer to parts that extend outward from the main body of the element and are typically associated with additional features that are not directly related to the bend itself. Edge lines may describe the outermost edges of a flat part but do not specifically address the relationship to bending. Thus, the precise terminology of mold lines is integral to understanding and executing effective metalworking processes.