Inventor General Discussion

Inventor General Discussion

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bhahn
Posts: 12
Registered: ‎05-22-2012
Message 1 of 6 (5,540 Views)

Interlocking joints in Sheet metal?

5540 Views, 5 Replies
04-30-2013 12:00 PM

I have been trying to work out how to make interlocking joints in sheet metal parts. The attached screen shot is the only way I have found to do it in Inventor, but it is a cheat. One of the flanges is a 85˚ bend because if it were 90˚ it would give an error "Flange Body intersects with existing body or self intersects." Can anyone think of another way of doing this that wouldn't have the error and wouldn't have to cheat the final shape?

 

Thanks

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mrattray
Posts: 2,493
Registered: ‎09-13-2011
Message 2 of 6 (5,536 Views)

Re: Interlocking joints in Sheet metal?

04-30-2013 12:04 PM in reply to: bhahn
You need to model the "teeth" a bit smaller to provide proper clearance. You'll need it in order for the part to be manufactured anyways, which brings me to another point. How do you plan to make that?
Mike (not Matt) Rattray

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JDMather
Posts: 26,651
Registered: ‎04-20-2006
Message 3 of 6 (5,525 Views)

Re: Interlocking joints in Sheet metal?

04-30-2013 12:34 PM in reply to: bhahn

Attach the file here if you can't figure it out.
In fact "cheating" is not the way to model the part.

There is a correct way.

Please mark this response as "Accept as Solution" if it answers your question.
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Contributor
bhahn
Posts: 12
Registered: ‎05-22-2012
Message 4 of 6 (5,520 Views)

Re: Interlocking joints in Sheet metal?

04-30-2013 12:37 PM in reply to: mrattray

Thanks Mike, your suggestion sparked me to try someting different that worked. Instead of making the flange the correct size and trimming away the "teeth" I have made the flange short and added the "teeth" to it with an extrude. As long as there is an "air gap" between the teeth (thanks Mike), it folds and unfolds correctly.

 

As for how to manufacure? I have already made a few with a metal cutting laser and hand bent the peices just fine. These will be small run items. - Once I work out the bugs.

Screen Shot 2013-04-30 at 12.36.56 PM.png

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mrattray
Posts: 2,493
Registered: ‎09-13-2011
Message 5 of 6 (5,511 Views)

Re: Interlocking joints in Sheet metal?

04-30-2013 12:43 PM in reply to: bhahn
I would avoid using tools from the 3D modeling tab (extrude). Stick with the sheet metal tools. Extruding things can lead to problems with unfolding a flat pattern if you're not careful.
Mike (not Matt) Rattray

Active Member
petedude
Posts: 6
Registered: ‎03-15-2010
Message 6 of 6 (663 Views)

Re: Interlocking joints in Sheet metal?

03-23-2014 11:26 PM in reply to: bhahn

I mastered this technique in 2010. You can see the results at

 

http://www.outfab.com/gallery.php 

 

I used integer math within an excel spreadsheet to calculate the interlocking fingers count and pitch. The math is strong enough that the number of fingers is independent from sheet thickness, and can also follow spline curves! I used the sheetmetal module to ensure perfect finger fit; I had to determine the neutral axis of my custom plywood as 0.75. 

 

I got this process really rockin and was ready to go to market when the machinery was relocated and everyone shifted interest. It's a shame since I led the world with the most complex and elegant fingerjoining designs.

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