iAssembly with a Component Pattern and Welds

[Hunteil]

Using: Inventor Profession 2019. (still waiting for them to upgrade)

Hello, I have an iAssembly I'm creating for a standard design with a family table... The assembly is simple, C shape with a gusset at each end and 1 in the middle. The length changes per the family table and when it gets longer it receives more gussets and when shorter it receives less gussets... I'm using the iassembly to reduce the qty of components in the component pattern and I use exclude to turn off welds too. Which usually retains everything until called upon. But in this case, when component pattern qty is reduced to 1 lower in value, it outright deletes the welds... Again normally this isn't an issue with constraints and other objects I exclude. So I'm confused on how I can make this work... Can you guys get the welds to return?

I went ahead and created a very simple example iassembly for you guys to test this on. Just open the file. (Hopefully it doesn't complain too much about paths). And activate the 2nd part in the part and you'll see that weld 5 is deleted, not excluded.

[johnsonshiue]

Hi! I think this is a limitation within assembly. It is actually not related to iAssembly. You can reproduce the behavior without iAssembly. Here is the proof.

1) Open Assembly1.iam.

2) Delete the iAssembly table.

3) Edit the pattern and change it from 3 instances to 2 instances -> Ok.

4) Repeat step3 and change it to 2 to 3.

You will see the weld beads are gone too.

The issue here is that when the number of instances drops to 2, it is as if the 3rd instance is deleted. All the objects depending on the 3rd instance will be gone. When the number is changed back to 3, it is like adding a new instance, which has no dependents.

This is a tricky case. I don't think there is an easy solution. I guess the best solution would be using iLogic instead. Basically, you build up an assembly and add weld beads based on the number of instances accordingly.

Many thanks!

[IgorMir]

With all honesty, Johnson - it looks like a bug. If I suppress the middle gusset and all corresponding welds - the welds get deleted. No matter in what order I suppress the objects.
Cheers,

Igor.

[Hunteil · Accepted solution]

So it hit me on the way home last night. Instead of a Component Pattern, just exclude parts not apart of the pattern will work just fine. So I'll do that as a workaround. 

Just yet another unexpected quirk with the Component Pattern feature.

[Hunteil]

I agree with @IgorMir though. We have a dozen or so assemblies where we have welds doing this and the engineers making these assemblies got frustrated with the welds disappearing or erroring that they've given up using the welds and manually writing them in on the drawings only.

I really wish the Component Pattern feature had less quirks like this. (still not sure if these quirks have been fixed in newer versions of Inventor though.)

[johnsonshiue]

Hi Folks,

Whether it is a bug or a limitation, the difference is the perspective. Regardless, the desirable behavior does not exist unfortunately. At the moment, I am not aware of a solution.

Many thanks!