Neutral Axis In Sheet Metal Bending

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

Neutral axis in sheet metal bending.

Neutral axis is a line where material is neither compressed or stretched. The k factor is the ratio of the neutral axis location t to the material thickness mt. The neutral axis is the zone or plane that separates the tension from the compression. Then input the bend angle to get the arc length bend allowance and bend deduction.

The neutral axis s behavior is the main reason the flat part needs to be smaller than the total of the formed piece s outside dimensions. The location of the neutral axis varies and is based on the material s physical properties and its thickness. Somewhere in between lies the neutral axis which is a line in the steel that is neither compressed nor stretched. The tighter the radius the bigger the opposing forces become bringing up the concept of minimal radius.

When metal is bent the top section is going to undergo compression and the bottom section will be stretched. When steel plate is bent the inside surface of the bend is compressed and the outside surface of the bend is stretched. Somewhere in between the thickness of material lies neutral axis. The arc length of the neutral line is the length of the sheet metal you have to leave for the bend.

The neutral axis position depends on the bend angle inside bend radius and method of forming. Input material thickness and and inner radius to get the data of k factor y factor neutral layer. The following equation relates the k factor to the bend allowance. In sheet metal bending process when metal is bent the material along the inner bend radius is going to undergo compression and the material along the outer bend radius will be stretched.

Inside bend surface is compressed whereas the outer bend surface is stretched. Our design engineers typically use a factor of 0 4 for our air formed press brake parts. Then input leg length a and b to get the flat size of the sheet. The line where the transition from compression to stretching occurs is called the neutral axis.

When you bend sheet metal the neutral axis shifts toward the inside surface of the bend. Notice how the sheet has thinned at the bend. Displaystyle k frac r frac ba pi a 180 t. 12 k r b a π a 180 t.