Neutral Axis
The layer within a bent material that is neither stretched nor compressed.
What it means on the floor
When sheet metal is bent, the outside fibers stretch (tension) and the inside fibers compress. Somewhere between them is a plane whose length does not change — the neutral axis. Its position is described by the K-factor.
Because the neutral axis keeps its original length, flat-pattern development is really the job of measuring length along it. Locating it correctly is the difference between parts that fit and parts that are short or long after forming.
Category: Forming
Applying the term
Interpret Neutral Axis in the context of the drawing, governing standard, and customer requirement in front of you — the same word can carry different limits in design, quality, and production documents. Check whether a stated value is nominal, minimum, maximum, or reference-only, and whether it applies before forming, after forming, or after heat treatment.