Sheet metal doesn't work if the faces of two flanges touch

[Anonymous]

This problem is best explained with an example.

If I make a design like this, using four flanges, then Inventor will produce a flat pattern for me.

But if I make a design like this, also with four flanges but where the fourth one touches the first, Inventor is not able to produce a flat pattern.

Why is this? How do I create a flat pattern for the second design?

I have noticed that, in the second design, the fourth flange seems to merge with the material from the first one, as if they're one solid. In reality, however, this would not be the case. Rather, the fourth and first flanges would touch but would not merge, a bit like two pieces of paper put on top of each other.

[jhackney1972 · Accepted solution]

The merging of material is the problem.  Inventor always merges material that touch.  If you cause a very small gap between the two flanges it will not merger and you will get a flat pattern.  A few thousands of an inch will do it and a sheet metal part will be just as accurate, only you will know.

Here is a screen shot and a part with a .002" extension of the top flange to prevent the flanges from merging.

[mdavis22569]

Can you share the part ..you need to shorten the bottom flange a bit ...as you can see here:

[JDMather]

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@Anonymous wrote:

....would not merge, a bit like two pieces of paper put on top of each other.

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Is there a reason you are not doing this as a single flange?

In you paper example - is there a gap between the atoms (or even molecules) of the faces of the sheet of paper?

[Anonymous]

Hey man, thank you for the reply.

I did actually consider this, but I thought there would be a more elegant solution. In the end, I took your advice and it has worked fine. When I come to making dimensioned drawings of the design, the 0.000001mm difference might be a problem, but I'll cross that bridge when I come to it.

[Anonymous]

Hey there, cheers for the response.

This is what I ended up doing and, so far, it has worked fine.

[Anonymous]

Hey dude, thanks for writing a reply.

I'll respond to both of your points separately.

1. It didn't occur to me to use the contour flange tool, but now that you suggest it I think it would be an interesting idea. However, I don't think I'm currently good enough with the tool to use it for my actual model. The screenshots I originally put on the forum were just to demonstrate the problem. My actual model looks like this. I think it would take me a very long time to model this using the contour tool.

2. Yes, there would be a gap but it would be in the order of femtometers and would, therefore, be small enough that the design would ignore it.

[Anonymous]

I had this problem recently, too.  If I remember correctly, I unfolded the existing flange (the one I'd merge with), created my new flange, then refolded the first one winding up with two adjacent flanges instead of a blob.

[paul.hadleyEBN96]

I see this is still an issue, its almost as inventor treat the sheet metal as standard body and start combining parts together again, when in reality the edges will glide against one another when formed but not actually bond. I don't think other CAD softwares suffers with this issue.

[johnsonshiue]

Hi Paul,

Within the same body, when two faces overlap, they are merged. This is the Inventor behavior, irrespective of Sheet Metal. When the faces don't belong to the same body, they won't be merged. Please share an example that exhibits the unreasonable behavior here.

Many thanks!

[salar_lotfee]

It's a sign that we should shift to solidworks right away, this software is not for professional use at all, so many bugs in so many areas

[SBix26]

Your contribution is also "not for professional use at all".  It contains nothing actionable, contains a broad and negative generalization, and has no examples to illustrate your point (this topic is not one, by the way).

Many professionals use Inventor for their everyday work.  Perhaps you could list a few examples of the "so many bugs", in a professional tone and with the intent to seek improvement.  Or perhaps you have misunderstood something about Inventor and we could clarify it for you.

This merging of coincident faces is not a bug.  A bug is a mistake in coding that produces unintended and incorrect results.  This is the intended result in Inventor, whether we users agree with it or not.  We may express our dissatisfaction with this intent and lobby for a change (see Inventor Ideas forum), but the software is currently performing as intended in this matter.  I would certainly welcome a change as described above.

I strongly urge you to make a similar post in the Solidworks support forums.  I am not a user of SW, but many former/current users posting here have mentioned the bugs in that application.  Perhaps you can help with two different apps that many thousands of people use every day for their livelihoods.

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Sam B

Inventor Pro 2026 | Windows 11 Home 24H2

[JDMather]

@salar_lotfee 

Attach your file here.  I will demonstrate why SolidWorks is not different, and the correct way in both softwares.