How can I calculate sheetmetal Length

[yhuang-2]

I set K factor in my sheetmetal model. But I don't know How can I check the sheetmetal length is correct or incorrect ?

I find the K factor formula But I calculate the flat length from K factor formula in the Creo Help.

That is different with result in Creo .

Below Picture

Picture A : add the flat, I use K factor :  0.5

Picture B : What is the formula that can calcalate the sheetmetal length ?

model in the attach

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[StephenW]

It's been years since I've done these calculations but with a K factor of .5, that is exactly in the middle of your material so if you sketched a "centerline" between your inside radius and your outside radius, you could just measure that length (or calculate that length using perimeter of an arc) plus the straight length on either side.

From a manufacturing standpoint, that would be wrong. Sheet metal stretches as it is bent so it's not exactly a centerline. Depending on your manufacturing, your K factor should probably be anywhere from .33 to .45. It all depends on what material is being bent and what manufacturing method is being used. I can't tell you what K factor you need to use.

Google how to calculate bend allowance. The math is not difficult but knowing the material and manufacturing method is very important to get accurate results.

[BenLoosli]

When I worked a lot with sheetmetal and A36 steel, we used a K-factor of .44.

Don't forget that Creo uses the Y-factor, from which the K-factor is calculated.

I have this a good introduction to understanding bending.

http://www.cutterod.com/cutter_zone/General/bending.pdf

[kdirth]

Calculation:

Blank Length (1 bend) = base length - inside radius - thickness + leg length - inside radius - thickness + (.5 x 3.14 x (inside radius + (thickness x K-factor)))

This matched the Creo flat pattern when I tried it.