The neutral line represents the material that doesn’t actually change or compress during the bending process, but just moves in the direction of the bend. The k-factor is the ratio between the thickness of the metal being bent and something called the “neutral axis/line.” The neutral axis is an invisible line that splits the thickness of the metal in half and runs all the way through the part.
This article and the accompanying video will explain everything you need to know about the k-factor and how it’s calculated. One of the more difficult concepts to grasp in sheet metal bending is the k-factor. We’ve covered a lot of information on designing for sheet metal bending and arranging geometry around bend lines, but understanding the terminology surrounding sheet metal bending will allow you to understand exactly what’s happening to your part during bending and why our guidelines are set up the way they are. What sounds like a relatively simple process actually involves a significant amount of complicated math, preparation, and terminology. Sheet metal bending is the process of using a CNC or manual brake to bend or form sheet metal into 3-dimensional shapes.
