topic Re: Sub-assembly loses constraints in Inventor Forum

Sub-assembly loses constraints

Anonymous — Wed, 31 May 2017 15:38:29 GMT

Hi All,

I have a subassembly of 6 in. piping layout that has a total of 9 parts with 2 iparts. So when we put it in the top assembly we have to make 1 part of it flexible, because it's used on the left and right and the top elbow needs to be able to rotate. We would like to use it on several platforms. There is a total of 3 constraints used, axis to axis twice and one flush mate. Everything is fine until we make that top elbow flexible; then every other constraint in the subassembly blows up. We have deleted all constraints and rebuilt it, we have deleted it completed and started from scratch. We're thinking it may be something with one of the iparts, we've eliminated everything else we can think of. Any help will be greatly appreciated.

LaMonte B.

Re: Sub-assembly loses constraints

mcgyvr — Wed, 31 May 2017 16:02:56 GMT

Can you post an example assembly (dont' forget to include all part files too)?

Or a clear image showing what you want..

At first I think.. Why don't they make that an iassembly with 2 members.. One left side/on right side..??

But I don't think I'm getting all the details..

Re: Sub-assembly loses constraints

johnsonshiue — Wed, 31 May 2017 17:01:13 GMT

Hi LaMonte,

Without seeing the actual assembly, it is very difficult to tell where the problem is. Since you mentioned it happened when you made one subassembly flexible, I guess it might be related to the subassembly. There are a few things to look after.

1) In the flexible subassembly, are there any component constrained to the origin planes or axes of the subassembly?

2) Is there any angular constraint? If yes, is it set to 3rd type, Explicit Reference Vector type and a stable rotational reference is selected?

3) Are there any pre-existing failed constraints?

4) Is any component adaptive?

5) Is any subassembly in non=Master Positional Rep?

Many thanks!

Re: Sub-assembly loses constraints

Anonymous — Thu, 01 Jun 2017 14:22:19 GMT

Unfortunately I can't post the entire top assembly, but this is the subassembly that seems to cause the problem. Once it put into the top assembly it has to mount flush to existing piping at the flanges and line up along the axis on the two vertical pipes. The only part the has to move is the elbow at the top. It can be a entirely different part, not related to this subassembly in any way but when I constrain the part to another part, again not related to this subassembly it blow up i.e. lose some of its constraints within the subassembly or reverse them.

Re: Sub-assembly loses constraints

mcgyvr — Thu, 01 Jun 2017 15:00:39 GMT

@Anonymous Posting an iam file without including all the part files too is useless..

An iam file only links to the parts and does not include them in itself..

Please post all the ipt files too..

Note you can also open the subassembly and then do a file...save as.. and select "pack and go" and then post a zip file of everything that way..

You can skip styles/templates,etc.. if you want..