K Factor Sheet Metal Bending

I had a question on k factors for our 3 d modeling software.

K factor sheet metal bending.

When metal is bent the top section is going to undergo compression and the bottom section will be stretched. The k factor in sheet metal working is the ratio of the neutral axis to the material thickness. K factor in sheet metal bending is a constant that is used to calculate sheet metal flat length. Our design engineers typically use a factor of 0 4 for our air formed press brake parts.

For example if the value of k factor for given material thickness and bending machines is known. The k factor is the ratio of the neutral axis location t to the material thickness mt. When you bend sheet metal the neutral axis shifts toward the inside surface of the bend. When sheets of metal bend the top surface compresses and the bottom expands.

Sheet metal flat length can be calculated using cad softwares. Of all the mathematical constants used in precision sheet metal fabrication the k factor stands out as one of the most important. In sheet metal design the k factor is used to calculate how much sheet metal one needs to leave for the bend in order to achieve particular final dimensions especially for between the straight sides next the bend. The k factor is defined as the ratio between the material thickness t and the neutral fibre axis t i e.

The k factor is the most important and elusive variable of bending because it varies both as a function of the material and according to parameters such as angle and tooling. It ultimately allows you to estimate the amount of stretch without knowing what type of material you are bending. And is typically between 0 3 and 0 5. The line where the transition from compression to stretching occurs is called the neutral axis.

The location of the neutral axis varies and is based on the material s physical properties and its thickness. In flat metal this boundary evenly bisects the material s thickness but it shifts when you bend the metal. It s a mathematical multiplier that allows you to locate the repositioned neutral axis of the bend after forming. The k factor depends on many factors including the material the type of bending operation coining bottoming air bending etc the tools etc.

It s the base value needed to calculate bend allowances and ultimately the bend deduction. Calculate k factor bend allowance and y factor for sheet metal bending. Therefore using k factor there is no need to calculate sheet metal flat length manually. K factor and y factor in sheet metal both look at how bending affects the material and how much bending the metal will allow.

The part of the material that bends without being compressed nor elongated.