Bend Definition Method (Neutral Factor)
Bend Definition Method (Neutral Factor)
(OP)
I am working on a design and am trying to understand the neutral factor. Can somenone explain this to me? Thanks.
Reggie
Reggie
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Bend Definition Method (Neutral Factor)
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RE: Bend Definition Method (Neutral Factor)
The neutral factor for a sheet metal bend defines the position of the neutral string inside the material. The value can be 0 up to 1 (outer side = thickness of sheet). If you take a look to a cross section of a sheet metal bend the neutral string is the material section, which will neithet be strengthen or compressed through the bending procedure. The neutral factor depends on the raw material, the bend angle and the bending machine. It used to calculate the bend allowance to determine the flatten length of the sheet. In our case we are using experimental neutral factors.
Regards
Matthias
RE: Bend Definition Method (Neutral Factor)
RE: Bend Definition Method (Neutral Factor)
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RE: Bend Definition Method (Neutral Factor)
When working with Sheet Metal design software, such as NX Sheet Metal, the 'Neutral Factor' can either be tied to a material library or by simply entering an explicit value. Note that there are material specifications where you can find recommended 'Neutral Factors' for specific materials. Of course you could also perform your own tests if it's critical for your application. For information about how to go about this, go to:
http://sheetmetal.me/k-factor/
However, there ARE certain 'rule-of-thumb' practices that can often be used for basic metal forming applications.
For many applications where it may not be critical you can often assume that for bend radii close to the material thickness, that for 'softer' materials you can use a factor of 0.33, and for 'harder' materials, a factor of 0.44 will often be acceptable. But keep in mind that there is a certain point, as the bend radius used is larger and larger as compared to the metal thickness, that one can often simply assume that there will be NO appreciable difference in the length of the formed versus unformed or flattened states. Unless tests indicate otherwise for the particular material and forming method used, you can often assume a 'Neutral' or 'K-Factor' of 0.50 when the inside bend radius is equal to or greater then 3 times the material thickness. But no matter what sort of material or forming methods are used, when dealing with homogeneous, isotropic materials, the 'Neutral Factor' can NEVER exceed 0.50.
Anyway, that should help you better understand how the 'Neutral Factor' is used.
John R. Baker, P.E.
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Siemens PLM Software Inc.
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RE: Bend Definition Method (Neutral Factor)