Albert,
Actually based on experience I had with SPI, Radan AutoSM and ProFold in
MDT, and now experience with Inventor there can be a significant difference
between parts that use different Kfactor or Bend allowances.
Many different people have their own variation on Kfactor and how it is
calculated. Inventor Kfactor is close to what I experienced in our own shop
but it doesn't take into account Sheetmetal material, and V-die sizes. It
is only based on 0.44(44%) offset of the neutral bend axis, which for most
situation is close but for others, can create a big difference (.010 - .05,
or more) per bend difference.
Stan McLean
"Albert Allen"
wrote in message
news:66487808A1CE2C0C8F2870B46C4E70F2@in.WebX.maYIadrTaRb...
> I did a simple bent up part in Inventor sheet metal by starting with a
flat
> plate,adding flanges and finally adding holes to each face. I then
developed
> the flat pattern and used this flat pattern in an idw with ordinate
> dimensions for the holes from a set corner. I also used the flat to show
the
> bend centers and specified an inside radius for the bends. Ok simple Simon
> stuff but when I sent it out to one of our vendors to be punched and bent
> they called back and said the bend allowances and the flat pattern did not
> jive with the drawing....what?! Turns out that when their engineer (who
uses
> SW) did a solid from my flat pattern and bent it on the lines I spec'd
using
> the same inside R that I used that things didn't work out. I have always
> used the default K factor in Inventor sheet metal and everything has
always
> turned out exactly as the model when it's built in the shop, so what gives
> here???? He did say that he uses K factors they load in from a spread
sheet
> into SW but there should not be more than a couple of thousands difference
> should there?
>
> Thanks,
>
> Albert
>
>