When sheet metal is bent, the outer fibers stretch, and the inner fibers compress. Somewhere in between lies the "neutral axis"—a theoretical line that experiences no change in length. DIN 6935 defines the position of this axis to calculate how much material is needed.
The DIN 6935 standard PDF can be downloaded from various sources, including: Din 6935 Standard Pdf
It is important to use the most recent version (currently ). The standard is copyright-protected and not available for free. You can purchase the official read-only PDF from: When sheet metal is bent, the outer fibers
Direct purchases can be made via national standardization portals. When sheet metal is bent
) decrease of approximately in the rounded portion of the bend.
The standard correlates the minimum inner bend radius ( rminr sub m i n end-sub