Inventor General

## Inventor General

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Posts: 161
Registered: ‎08-27-2012
Message 1 of 4 (318 Views)

# Sheet metal fold puzzle

318 Views, 3 Replies
03-11-2013 01:49 AM

O.k, if anyone is in the mood for some mental gymnastics this morning:

The left-hand part was created by someone else, using the bend part command in the "modify" tab.

The right-hand part was created by me using fold in the sheet metal environment, using the same sketch.

Why, please why, is my part shorter?

Inv 2013

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Message 2 of 4 (278 Views)

# Re: Sheet metal fold puzzle

03-11-2013 05:20 AM in reply to: BarryZA

Bend Part command is not a sheet metal tool and doesn't take account Bend Allowance (sheet metal stretches when bent).

I wound not have used either method to create this part.

I am away from my Inventor computer so can't provide a demonstration on easy technique to model.

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Message 3 of 4 (274 Views)

# Re: Sheet metal fold puzzle

03-11-2013 05:23 AM in reply to: BarryZA

The Bend tool sets the neutral axis of the material at the sketch plane, I believe, since Inventor knows nothing about the bending properties of the material; this makes the material deformation in this case all stretch and no compress.  The fold tool in Sheet Metal sets the neutral axis as directed by the active Sheet Metal Unfold Rule, by default at .44 times the thickness (or nearly halfway through the material).  So I expect that the sheet metal version would be more accurate.

Best practice, though, is to model sheet metal parts in the folded condition and let Inventor work out the flat pattern based on your k-factor or bend table for the specific material and forming tool.

Sam B
Inventor 2012 Certified Professional

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Posts: 161
Registered: ‎08-27-2012
Message 4 of 4 (273 Views)

# Re: Sheet metal fold puzzle

03-11-2013 05:23 AM in reply to: JDMather

Thank's JD (as usual)

I was thinking K-factor had something to do with it. The sheet metal one is mine, the other one from the previous guy - for the record

I want to see if I can round off the decimals in the folded model and model it like you said sblixer. Nothing like being paid to fix someone else's mistakes.

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