Tim,
We would sure like to have a copy (with formulas & unprotected). Our "sheet
metal" tends to run more on the side of "plate", so we need to expand the
table. This is the best example I've run across yet - much better than the
stock sample.
Thanks in advance,
Gary W. Lynn
glynn@westerntrailer.com
"Tim W." wrote in message
news:40cf509f_2@newsprd01...
> Dan Z., this is especially for YOU. However, it also applies to everyone
> using Sheet Metal in Inventor:
>
> I've created an excel spreadsheet to figure out K-factors and Bend
> Allowances. Right now it works with "Inches" as the unit of measure.
>
> I too have been upset with how complicated it is to modify K-Factors and
> Bend Tables. I don't use the same equation that Inventor uses, I use this
> one for Bend Allowance:
> Bend Allowance = [ ( Thickness x F-Factor ) + (Bend Radius x 1.57 ) ] x (
> Bend Angle / 90° )
> The F-Factor which is specific to steel, hard brass, copper, and
> aluminum is 0.64.
> Use an F-Factor of 0.55 for soft brass & soft copper OR 0.71 for
bronze,
> hard copper, and spring steel.
>
> Then, I use this one to determine the K-Factor from the Bend Allowance:
> Bend Allowance = PI x ( Bend Angle / 180° ) x ( Bend Radius + ( K-Factor x
> Thickness ) )
>
> Re-arranging it to solve for the K-Factor, the equation becomes:
> K-Factor = [ Bend Allowance / PI x (Bend Angle / 180°) - Bend Radius ] /
> Thickness
>
> There are some other things I threw in to the equations like unit
> "round-off", and something I call "small bend angle correction". There
are
> also two Bend Tables included - one for the specified Thickness & Bend
> Radius only, the second includes editable Bend Radii and the specified
> Thickness. Both go from 0 to 180 degrees in 1 degree increments. These
> worksheets should be saved as txt files and imported into your current
sheet
> metal style. BUT you've got the option to use just the K-Factor, OR just
> the Bend Table, Or both (by using different Sheet Metal Styles).
>
> Because I don't want anybody tampering with the equations, the worksheet
is
> password protected. I've also hidden the equations for now. This is
mainly
> because I've put a lot of work into it, and I don't want someone suing me
if
> they change something to make it calculate incorrectly.
> However, I will send an "unprotected" version directly to YOU if you post
an
> email address that I can send to. (feel free to encrypt the address to
avoid
> spammers, but just make the encryption something I can decipher).
> ...
> I haven't re-written it to work with "mm" yet, because I don't use those
> units for sheet metal. However, I think it still works without too much
> hassle if you just ignore the units.
> For now, wherever it says "in" think "mm". Obviously, you'll have to use
> the Custom Thickness feature exclusively.
> In the case of exporting a bend table, be sure to switch the units in the
> resulting *.txt file BEFORE importing it into Inventor!!
> The next version may include a switch for "mm".
>
> Please post any questions / concerns / differing ideas to the NEWSGROUP
> only! Also, be sure to read the instructions tab to learn how to use it
and
> see a list of my assumptions.
>
> Best wishes, Tim W.
>
>
>
>
>