bend table question

[Anonymous]

Hello,

Ive been using a static k factor and its been working for me fine until we got a new die and it doesn't work with our k factor i have set up.

So now im trying to set up a bend table for different radii and everything so i dont need so many templates for different dies and such.

Only problem i have is, i don't know how many pieces i need bent/how many angles i need to record.

Our shop primarily uses 4 different gauges of Stainless Steel.

If i have them bend me a piece 4" x 4" at 45, 90, 135 degrees; could i make my bend table off of those numbers?

Or do i need them to bend me pieces all 5 degrees off of each other like all the other tables Ive seen?

Also when it comes to bend tables, the columns on the left are the angle and the top is the radius, but how do i get the numbers to fill in these spaces? i saw a formula of L=A+B-x from 

https://knowledge.autodesk.com/support/inventor/learn-explore/caas/CloudHelp/cloudhelp/2019/ENU/Inve...

but Im still in the dark about using that since i dont completely understand it at the moment.

Any help is greatly appreciated 

[johnsonshiue]

Hi! On a Bend Table, a few things are a must. Thickness, Bend Radius, Bend Angle, and the corresponding allowance.

For your case, it is indeed better to have at least bend columns for 45, 90, and 135 deg. You can certainly add columns for angles between those angles to boost accuracy (optional). Otherwise, the bend allowance for in-between angles will be interpolated based on existing columns.

Many thanks!

[Anonymous]

Oh okay, so lets say i need a 67.5 degree bend, it would just take the numbers from the 45 and the 90 and get the average and use that?

And i have a k factor calculator which would give me the k factor but just to be clear, the corresponding allowances depend on the material thickness, not the radii of the die we are using?

[CadManagerMoffatNZ]

We did the folding the blank exercise to get the k factor for all our tooling and gauges.

From this we then used an excel table using the formula below to create full bend tables.

Getting  fully populated bend table takes time and patience but the rewards are well worth it in accuracy of fit finish etc

Hope this helps

[johnsonshiue]

Hi! Yes, I believe it is how it works when the bend allowance for a particular angle isn't on the table. Bend table also require you to specify the bend radius. K factor is a relatively straight forward way to calculate bend allowance.

If you have an equation to define the bend allowance, Inventor can take that too.

Many thanks!