topic Re: Lofted flange creation failed in Inventor Forum

Lofted flange creation failed

Anonymous — Thu, 28 Sep 2017 22:12:14 GMT

Hi,

I have been doing lots of lofted flanges for my 3-D sheet metal animals and have run into a problem when I try to create the lofted flange between these 2 profiles:

BottomLeftInsideLeg, BottomLeftOutsideLeg

Here is the error I see:

Sheet Metal: Lofted Flange Creation failed.
Longhorn-6.ipt: Errors occurred during update
The attempted Lofted Flange operation resulted in overlapping bends. Try with a smaller bend radius.
Feature Compute failed.

Any suggestions for how to fix this problem? I am using .0598 in for the metal thickness (16 guage steel).

Thanks,

Elaine

Re: Lofted flange creation failed

johnsonshiue — Thu, 28 Sep 2017 23:55:29 GMT

Hi Elaine,

I think the issue is with the small segments at the top of the sketches. There are small arcs and line segments. I don't think you need those. You should consider deleting those small segments and arcs and re-intersect the lines. The tiny geometry will cause troubles down the road and it does not represent any design intent. Please take a look at attached part. I am able to create a lofted flange after changing a few lines to construction lines.

Many thanks!

Re: Lofted flange creation failed

Anonymous — Fri, 29 Sep 2017 11:02:39 GMT

Thank you Johnson. I will be more careful about the tiny lines. What I usually do is use Sketch Doctor to help me fix up any open loops or overdrawn curves. Sometimes Sketch Doctor automatically closes loops. Some of this should be done correctly from the beginning (by me!).

Thanks again for you help.

Elaine

Re: Lofted flange creation failed

johnsonshiue — Fri, 29 Sep 2017 16:22:06 GMT

Hi Elaine,

You are more than welcome! Let me explain why Inventor or any 3D feature-based parametric solid modeling CAD is picky about this kind of issues. First, not all CADs are equal. Some systems can generate pretty nice looking images or models on the screen but the object you see cannot be made in reality. Or, it does not look the same when you make it. For mechanical CAD like Inventor and our direct competitors, the objective of designing something is to make it. The geometry has to be precise up to certain tight tolerance (10E-5mm). So, any geometry bigger than the tolerance is considered a different piece of geometry. Although human eyes cannot discern such tiny difference, this tight tolerance is there for a reason. The geometry created by mechanical CAD like Inventor is the ideal shape that you can manufacture (subtractively or additively). You want to make sure the ideal shape is reasonable and you will make the real object as close to the ideal shape as your budget allows.

The other objective is to create a list of components (material list or BOM or partslist) showing the laundry list of things constituting the assembly. You may not make every part but you will know what you need to have (make or buy). The general rule of thumb using mechanical CAD is to simplify as much as reasonably possible. You cannot change the design intent but you do want to avoid making things overly complicated. Complication adds costs and makes the model hard to edit, maintain and make.

Many thanks!