How to make a simple mate between 2 rods and a support?
trenton_carr
Member Posts: 18 ✭
Hi
I'm trying to mate 2 holes in a support bar to 2 rods but it refuses to mate.
I've made revolute mate to the 1st rod and after that I cannot get any other mate to work to match up the 2nd rod.
Assembly works fine in SW and Creo. The shaft is not connected in any way.
Hole and rod centres are exact.
Any assistance please?
Thanks.
I'm trying to mate 2 holes in a support bar to 2 rods but it refuses to mate.
I've made revolute mate to the 1st rod and after that I cannot get any other mate to work to match up the 2nd rod.
Assembly works fine in SW and Creo. The shaft is not connected in any way.
Hole and rod centres are exact.
Any assistance please?
Thanks.
0
Best Answer
-
Could this not have been assembled with a single Fasten mate and an angular offset of 45˚?5
Answers
-
If the support bar is supposed to be movable in z I'd use two cylindrical mates. If it is to be fixed in z I'd use one cylindrcal and one rotational mate. Using two rotational mates can easily lead to overdefined mates since both will try to fix z.
0 -
In addition to @lutz_niggl I want to take a step back to make sure that you understand how our mates work. They are fundamentally different from SW and Creo. For more information on how mates in Onshape work you can look here: https://cad.onshape.com/help/#mate.htm?TocPath=Assemblies|Mates|_____00
-
Support bar is not movable and I've tried all the mates as stated in OP.lutz_niggl said:If the support bar is supposed to be movable in z I'd use two cylindrical mates. If it is to be fixed in z I'd use one cylindrcal and one rotational mate. Using two rotational mates can easily lead to overdefined mates since both will try to fix z.
I cannot seem to find the reason.
0 -
If you can give me access to your document I can have a look at it. It should be really simple to fix.
If sharing is not an option you can have a look here: https://cad.onshape.com/documents/162727ed93bbb391c1a00286/w/bea92ea5a9b177b871e64254/e/3b3d41d0cd19f0609e611aa7
0 -
Here's the link, thanks for looking.
https://cad.onshape.com/documents/580793fe106cdf112af16d66/w/00444d4baa4cef48f38769aa/e/53eb9c35f72a9d258dad426c0 -
@trenton_carr unfortunately I have to leave for a couple of hours. If nobody else is helping you meanwhile I'll have a look later.0
-
Is the center distance between the outer holes in the gimbal the same as the distance between the studs (Part 1)? They look a little off to me.0
-
0
-
@trenton_carr: I can reproduce your problems with mating the support bar to the rods. @michael3424 is correct, the distances of the holes in the motor do not exactly match the distance of the holes in the bar. (Looks like the deviation is smaller than the displayed accuracy)
To check this I redesigned the support bar with the correct distance (sqrt(2)*31mm). This bar can then be mated to the rods without any issue. The red bar is the new one, the gray is the original bar.
Here the corresponding document:
https://cad.onshape.com/documents/5807ed1a26b0d21143965d65/w/6a102689003bc09d6c2247e6/e/e0d10fe051caea25d2a7b568
0 -
Thank you very much for helping find the issue.
I've tried to find the root of the problem so had a look at the source file in Creo.
Accurate to 4 decimal places, I can only assume then that a rounding error happens either during export to parasolid or importing from parasolid.
Either way I cannot spent time remodelling parts that should fit.
Thank you for your help once more.0 -
Quite interesting, I also belive that this is some rounding effect in either the importer or the exporter. Here a screen shot of a distance measurement in Onshape. It shows a small deviation in y direction which is probably the reason for the issue. I think this is something Onshape should have a look at.
0 -
Could this not have been assembled with a single Fasten mate and an angular offset of 45˚?5
-
Thanks, this does work, but does not explain the underlying problem.brian_brady said:Could this not have been assembled with a single Fasten mate and an angular offset of 45˚?0
