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Dale_Rosema
23-Emerald III
Dale_Rosema23-Emerald III
23-Emerald III
February 14, 2019
Solved

Cylinder with a hole / two insert mates (Part 2)

  • February 14, 2019
  • 3 replies
  • 3476 views

Several years ago (14-JAN-2013) I had an issue where I have two insert mates (both coincident because they are perpendicular) where the part was flipping to one of four different orientations:

 

https://community.ptc.com/t5/Assembly-Design/Cylinder-with-a-hole-two-insert-mates/m-p/57404

 

I am now in Creo 4.0, and the previous solution, adding to coincident constraints for (2) plane is no longer working. When upgrading to the newer version of Creo, the coincident constraints were changed to "Parallel". There in lies the problem, two planes can be parallel in one of two configurations when they are aligned and when one of the planes if flipped 180 degrees (unless parallel also includes a orientation vector to say what side of the plane is "up").

 

tube-part.PNG

 

Any thoughts? Is this a new bug with the constraints changing from coincident to parallel?

 

Thanks, Dale

Best answer by Dale_Rosema

Errant mate solved the issue. The part was mated to the wrong plane that was in a similar placement to the plane to which it should have been mated. Lesson in double checking your mates. G'day mate.

3 replies

Dale_Rosema
23-Emerald III
Dale_Rosema23-Emerald IIIAuthor
23-Emerald III
February 14, 2019

I had also made an idea request to correct this:

 

https://community.ptc.com/t5/Creo-Parametric-Ideas/Two-inserts-is-not-fully-constrained/idi-p/465609

Patriot_1776
Patriot_177622-Sapphire II
22-Sapphire II
February 14, 2019

'Morning Dale!

 

Yeah, I think the constraints in creo 3 are a step backward, although, "automatic" seems to be a good thing.  Still have to play with it more to 100% be convinced.  I liked the older "mate".

 

One thing you might try, is datum planes and surfaces act differently when trying to mate them.  Mates on 2 solid surfaces seem to be more stable because creo knows the surface normal always faces out.  With datums, it's the brown side now that has the outward normal.  This is why my library fasteners always use solid surfaces instead of datums in the pre-defined placement constraints.

 

I agree it could be more robust.  One thing I liked about NX 8.5 was that you could use a "concentric" (I think it was) constraint that would align the center of 2 circles AND make them coplanar.  That was nice.

 

Best of luck!

Dale_Rosema
23-Emerald III
Dale_Rosema23-Emerald IIIAuthor
23-Emerald III
February 14, 2019

The weird this is that the generic shows it in the correct configuration, but the instance on one of the four feet is flipped so it is on top of another foot that is already there (and makes it look like one is missing - though it shows up in the model tree).

Patriot_1776
Patriot_177622-Sapphire II
22-Sapphire II
February 14, 2019

Are the feet ref patterned from a hole or something?  If the 4 radial holes were done as 2 holes thru both sides patterned at 90deg as opposed to 4 separate holes thru one side only patternd at 90deg, that might do some weird things.  But I can't imagine an instance flipping if the surface is the same (i.e. from the same feature).

Dale_Rosema
23-Emerald III
Dale_Rosema23-Emerald IIIAuthorAnswer
23-Emerald III
February 14, 2019

Errant mate solved the issue. The part was mated to the wrong plane that was in a similar placement to the plane to which it should have been mated. Lesson in double checking your mates. G'day mate.

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