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Redro1-Visitor
1-Visitor
November 4, 2015
Solved

k factor

  • November 4, 2015
  • 8 replies
  • 4915 views

hello

i want to solve a problem with flat pattern in creo

how it is best k factor for steel , for a very good sheetmetal in reality

i use k=0.5 but this factor do not reflect reality flat pattern, i need to make some corrections for a best flat

exist  best ruls for optimizing flat pattern (right habits )?

is it somebody how corelate salvagnini and creo for best results without corrections?

please tell me a best k factor and important ruls in calculate developed lenght

tks


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    Best answer by TomD.inPDX

    Technically, a K factor of .5 should be in the middle to the developed length is simply the mean length along the center of the formed part.

    The only variation you should see from one CAD package to another is when the inside bend radius is changed.

    Otherwise, it is easy to measure with a sketch over the formed part.

    Somewhere in the back of my mind I seem to recall testing this theory, and if I remember right, Creo came up with the right answer.

    8 replies

    BenLoosli23-Emerald III
    23-Emerald III
    November 4, 2015

    The K-factor will vary depending on the actual material and the type of forming you are doing.

    Where I used to work, we used 0.44 (Y Factor = 0.69115) and that worked out well for our processes.

    BenLoosli23-Emerald III
    23-Emerald III
    November 4, 2015

    I did a test with a 'U" shaped part.

    The 2 end flanges were 1.5" tall from the outside and there was 5" between the 2 outside walls.

    Part thickness was 0.25" and the inside bend radius was 0.5"

    With a Y-factor of .5 (Creo default) the flat pattern ws 7.0354" long.

    With a Y-factor of .69115 (K-factor of .44) the flat pattern was 7.1312" long.

    Reference pages explaining K-factor and Y-factor.

    SheetMetal.Me – K-Factor

    SheetMetal.Me – Y-Factor

    StephenW
    StephenW23-Emerald III
    23-Emerald III
    November 4, 2015

    Wow, that takes me back to the good old days (well, maybe tough old days) of hand calculating flat patterns. I designed much simpler parts then, because if I didn't, I had to figure out the flat pattern!!!

    TomD.inPDX17-Peridot
    17-Peridot
    November 5, 2015

    I use the rule of thumb method... 60% stretch/40% crush... for simple sheet-metal forming.

    There is more deviation for a give dye in the resulting inside bend radius.  ...Or if the die is coining the bend.

    Redro1-VisitorAuthor
    1-Visitor
    December 2, 2015

    i have a problem and i don't understand

    i have 0.6 thickness ,

    i chose k=0,5 in creo , and 0.5 in other 2d program

    but developed lenght is different what is the reason for this

    was happened?

    where i make mistakes?

    1.jpg

    tks in advance

    BenLoosli23-Emerald III
    23-Emerald III
    December 2, 2015

    Creo uses the Y-factor by default while most other software uses the K-factor.

    Did you set the sheetmetal module to use the K-factor value or just use the default value, which would be a Y-factor of .5?

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