Help with sheet metal part

[ebswift]

I'm struggling with this concept of designing a fairly simple sheet metal part with a bend around a curve (see attachments).  This design was done by someone on the web, the drawings are readily available for download.  The part I'm having trouble with is the part with the curve that has all the little individual tabs which are bent as per the Lid Assembly attachment.

Since I'm learning as I go, rather than simply blindly copying measurements to make all the little tabs, is there a way for Inventor to plot the tabs automatically according to what you want as an end result?  My thinking is to somehow design the sheet metal part in 3D with the bend, then have Inventor flatten the design, thereby splitting/tearing all the little tabs automatically.  Logically I think having some split limit would allow the number of tabs to be controlled so we don't end up with a million splits.  The other reason I don't necessarily want to copy the measurements is because I want to change some of the scaling, and I want to introduce two holes per tab rather than one.  So dynamic fold/unfold features here would help greatly.  Once I have the folded design, obviously I need to translate the holes to the lid so they match up, which is challenge #2.

I will try to ping the original designer to see what software/techniques were used, by all appearances it doesn't look like this design was manually hacked together, it looks like some dynamics were involved.  I hope someone can help with this, so far I've enjoyed working out how to use feature patterns and other basic features of Inventor that make for great time saving.

[blair · Accepted solution]

Don't think of it as a curved shape. Think of it as a number of flat tabs where each one is bent by individually. The drawing dimensions denote it should be a complicated sketch and then each "tab" should be bent. I think it would be easier to create the "main flat plate" with a number of "flats" along it's edge and then use the Flange Tool with the "Round" corner relief.

Since they give all the X-Y coordinates for the "flats" and then make the last 2 equal, will produce all the flats to create the flange.

[ebswift]

Hi Blair, thanks for the response.  I get your reply (nice reproduction too!), though my complication comes in when I change the dimensions of the end part - I want to increase the height of that end plate which changes the dynamics of the curve.  I no longer have the exact dimensions given from the original drawing given the new dimensions, I need to extrapolate the new tab sizes/positions.  This is something that can be figured out with some maths, though what I was wondering is if Inventor can do some of that figuring out for you?

Hoping that I haven't misunderstood the suggestion, I really appreciate the feedback and the time you took to make a working example, still learning here :).

Edit:

planned lid end total height (folded) = 161mm

lid end total width (folded) = 115mm

tabs folded = 20mm

This is what will change all the tabs.

[blair]

The way they have it dimensioned, it would be pretty hard. Possibly if one spent some time on it it could be driven by a few parameters.  

[ebswift]

I've done a LOT of figuring out with this software and I couldn't make anything work with an arc, so I segmented the arc into straight lines before making the sheet metal flanges.  I also worked out how to fit the curve over the two given edge lengths.  It's not perfect, I welcome suggestions on how to make the tolerances more perfect rather than what I've done which is a kind of "close enough" approach, which is not in the spirit of precise CAD design.

https://www.youtube.com/watch?v=3oLid1EWq2w&feature=youtu.be