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Re: Understanding assembly relations

Gears Esteemed Contributor Gears Esteemed Contributor
Gears Esteemed Contributor

... PS.: @Hans11

 

 

I suppose to upload those part will not be possible?

 

 

regards
Wolfgang

Re: Understanding assembly relations

Phenom
Phenom

Have you tried a restarting SE, sometimes this will help when otherwise perfect parts fail to assemble?

 

 

Re: Understanding assembly relations

Genius
Genius

Thany You all for Your helpful input.

To continue ...

 

 

Dear Wolfgang,

 

do I understand right, that You suggest to use manual positioning instead of using assembly relationship to overcome the alignment error?

 

With some brain acrobatics :-) I realize that each aligning of axes suppressesin total 4 degrees of freedom, i.e. suppressing movement along the two axes vertical to the aligned axis and rotation around these two axes. Two degrees of freedom remain - the rotation around and the movement along the aligned axis.

If I apply axis alignment a second time, again I suppress four degrees of freedom ... but only two freedom degrees were left. The consequence the situation is overdetermined. This is fine, if the determination was identical by the two enforcements, i.e. that the symmetry axes of cylinder and bore hole meet eachother somewhere.

 

A thought experiment for illustration

I checked the angle between the hole's symmetry axis within both parts using Inspect/3Dmeasure and found them to be 90° exactly, even using the 7digit rounding. So for my understanding 2 lines alignment should work without conflicts.

Defining the big cylinder's long axis is along the Z-Axis and its bore hole axis is oriented along the Y-axis, while the second body is oriented differently.

The first aligning of both parts results they are aligned along their common Z-axis (X=0, Y=0), that means they only can move along the Z-axis and rotate around the Z-axis.

The second aligning along the bore hole's Y-axes can easily rotate the second body's along the Y-axis as this rotation around the Z-axis is free. The potentially conflicting point is the location of both bore hole's axis have to be centered at X=0. That is given for long axis of both cylinders but needs to be fulfilled for the bore holes. I.e. their both axes have to be oriented cutting through X=0 and Y=0.

 

The question arises: How can I practicely check this with Solid Edge?

 

(Yes I already  measured the angle between the axes to be exactly 90° with 7 digits rounding, but is not sufficient to detect lateral offset)

 

best regards

Hans

Re: Understanding assembly relations

Gears Esteemed Contributor Gears Esteemed Contributor
Gears Esteemed Contributor

If you don't want to or can't seem to get the alignments perfect but in actuality the models are "good enough" you can use other alignment relations. For example you could leave the axial one for the large diameter, then use connect relations (which are single keypoint constraints, like a vertex to a plane for example, which would only constrain one axis each) to position and lock down the part. I seriously doubt if @hawcad meant to manually locate anything.

Bruce Shand
SE2019 MP5 - Insight - Win10 - K4200

Re: Understanding assembly relations

Gears Phenom Gears Phenom
Gears Phenom

@Hans11,

 

Share your models...   Pretty Please...

 

we can show something in a :30sec video much better than trying to explain in words...

 

dumb down the geometry if/as needed

Matt Johnson
Solid Edge Certified Professional
Solid Edge 2019 (SEEC) - Production
NX12 (Tc Integration)
Teamcenter 10.1.7

Re: Understanding assembly relations

Gears Esteemed Contributor Gears Esteemed Contributor
Gears Esteemed Contributor

Hi @Hans11

 

 

 

no, no and another no, I never ever would think about manaually position anything in an assembly.

No, what I mentioned and whta was correctly interpeted by @bshand was, that You should take care that Your basic geometry in every single part is 100% correct.

So it could be that one hole axis is not 100% crossing the main hole axis.

If this is the case You never, ever (again) would get it assembled as wanted.

It simply is not possible, just mathematically explained.

 

Here is the point where You have to start.

 

And Yes also as said by @Johnson_BigMatt provide the parts and everybody will be able to help You within a minute.

 

 

 

 

regards
Wolfgang

Re: Understanding assembly relations

Gears Esteemed Contributor Gears Esteemed Contributor
Gears Esteemed Contributor

Hi @Hans11

 

 

 

and to add another sentence to that:

 

"What I have seen the last 23 years with Solid Edge, was, that in 99.99% of any situations, where an assembly relation could not be created, the reason was a poor or uncorrect geometry!"

 

regards
Wolfgang

Re: Understanding assembly relations

Genius
Genius

Yes, in my longer text I already agreed that I suppose poor geometry is the cause. (May be I should write shorter for not loosing the educated reader, but I write long for people at a level like mine).      I suppose that the inserted body, which I received from another platform and attach to this post, has an insufficiently precise geometry for relating assemblies in Solid Edge.

 

What I asked was: How can I practicely check this geometry with Solid Edge? How do I check if symmetry axes a meeting in one point?

 

Wolfgang, sorry if I misunderstood You, but You wrote  "... so select the smaller holes and use the steering wheel to move it to the center of the larger hole. "which  sounded to me like You were suggesting manual adjustion, while I could not imagine You would recommend this.

 

 best regards

Hans

Re: Understanding assembly relations

Gears Phenom Gears Phenom
Gears Phenom

nothing jumping out at me...  how about the male part?

 

and/or...   have you tried the dual axial aling from only the geometry on the small end...  it has its own "major diameter" as well as the thru hole...?

 

can you share the mating part.

Matt Johnson
Solid Edge Certified Professional
Solid Edge 2019 (SEEC) - Production
NX12 (Tc Integration)
Teamcenter 10.1.7

Re: Understanding assembly relations

Genius
Genius

:-) I just thought to check, if the other body had the bore hole axis crossing the long cylinder's axis. Therefore just  only the male part. I attach now the female part.

 

By the way parallel one axis, parallel second axis and mate the flat part works without conflict. I think that supports the assumption, that one of the small bore holes is not crossing the center of the long axis.

So finally this is a workaround, but I try to learn with every step. So I'm looking how I can check for the cause.

 

Hans