Bend Relief Depth

[shastu]

Can someone please explain to me why the Bend Relief Depth does NOT seem to change anything? I should see the width of my flat pattern change when I change the Bend Relief Depth, but it doesn't. Am I missing something?

[shaney]

The bend relief depth is the length of the cut inventor makes at the end of a flange where the sheet doesn't stop. It is for "bend relief" which is to allow for a more precise bend. Without this "bend relief" the metal has to tear at the flange ends to bend. We don't use bend reliefs because they require more camming and we don't seem to benifit from them.
I believe you are thinking of the effect the bend radius has on the size of the flat pattern.

[shaney]

I should say we try to not use bend reliefs but sometimes they are required, depending on the shape of the part.

[shastu]

Well, I'm still not sure based on your description what that bend relief depth is but let me ask things a little differently. When Inventor creates the flat pattern, it seems to me like the bend is being made from the middle of the part or half of the thickness. That is not true to our bends in the real world and therefore our flat patterns are going to be off. We need to have the ability to change how the bend is made based off of the thickness of the material. Maybe a picture will help. Look at the attachment. Is the bend figured from the middle of the thickness as shown in the attachment with a green line? If so can we change it to something else.

[Anonymous]

Shastu:

I think the parameter you want to adjust is the kFactor which can be
found in the sheet metal styles dialog.

Richard

shastu wrote:
> Well, I'm still not sure based on your description what that bend relief depth is but let me ask things a little differently. When Inventor creates the flat pattern, it seems to me like the bend is being made from the middle of the part or half of the thickness. That is not true to our bends in the real world and therefore our flat patterns are going to be off. We need to have the ability to change how the bend is made based off of the thickness of the material. Maybe a picture will
> help. Look at the attachment. Is the bend figured from the middle of the thickness as shown in the attachment with a green line? If so can we change it to something else.
>
>
> ------------------------------------------------------------------------
>

[shastu]

Yeah, that is what I am messing with right now to see if I can get it to work? Thanks!

[JDMather]

Sounds like you are getting Bend Relief mixed up with Bend Allowance (Unfold Method). You can set up the bend allowance by KFactor or experience spreadsheet.

BTW - depending on who is doing the manufacturing it might be best to simply give the final folded dimensions and let them figure out how to get there. If you give them flat pattern dimensions that don't match up to their equipment bend allowances they might come back and say - we used the information you gave us.

[shaney]

On the attached jpg the bend relief depth is 0.2" and the bend relief width is 0.1".
I'd like to know what method you develop for getting the bends accurate. Ours works OK but I am sure could be better.

[shastu]

Next question, the Kfactor needs to change based off of certain criteria. Therefore, I think I will need to to use a bend table in order to determine the Kfactor. I have looked at the help file and I may be able to figure it out from there, but if anyone has other examples that would be great. You can change all the numbers to bogus numbers if you want. I just need the format for the text file.

[Anonymous]

Just an example...

Are you using 2017? The attached part is drawn in 2017. If so, your Relief Depth "B" and Relief Width "A" will be dictated by the thickness of your metal. For instance, with a thickness of .125 and using a k factor of .43 and Bend Radius of .08 your Relief Width "A" will be .210 and your Relief Depth "B" will be .205.  Now, change the thickness of your metal to .0625 and your k factor to .38 your Relief Depth "B" will change to .143 and Relief Width "A" to .163. 

In earlier versions you could dictate those values in your Sheetmetal Default but in 2017 it will not allow it.

Thank You,

Tonya Sweeting