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How-to Mate Sphere to Hole Edge?

jabster42

New member
Hi.

Could someone tell me how to mate a sphere to a hole edge?

I have a part with a thru hole and a c'bore, and I want to drop the sphere into the c'bore and have it stop on the edge of the thru hole. Please see the attached picture.

Any help is appreciated.

Thanks,
john
 
Create an Insert constraint between the sphere and the hole, then create a Point on Surface constraint. Pick an endpoint of an arc that makes up thehole (or create a point), and pick a surface of the sphere.
 
Here's my quick and dirty (fully parametric though) way to do this. I haven't hidden the extruded surface for visualization purpose:







Edited by: marker4x4
 
CRang72 said:
Create an Insert constraint between the sphere and the hole, then create a Point on Surface constraint. Pick an endpoint of an arc that makes up thehole (or create a point), and pick a surface of the sphere.

crang72,

For some reason, that is not working for me. That is what I tried before posting here. I initially was using an axis align sphere-to-hole, but also tried your insert idea. Either way, whenever I add the point-on-surface mate, I get an invalid constraints error. Also happens in 2001. Tried using an arc endpoint and individually created points. I even tried flipping the axis-align, to no avail.

Marker4x4, I'm not exactly sure what you did there. I'm just starting to use WF4.0 (coming from 2001).

I'm using the M020 build.

thanks,
john
 
Well, my Friendly Neighborhood PTC App Engineer figured out the problem:

The parts are created in mm-units, but the assembly is in inch-units. Once I switched the assembly to mm, it mated just fine.

-john
 
jabster42 said:
Marker4x4, I'm not exactly sure what you did there. I'm just starting to use WF4.0 (coming from 2001).

I'm using the M020 build.

thanks,
john

First I've assembled temporarily the sphere to the bore using insert and tangent.
It places the ball TANGENT to the btm. of the C/bore. Next I ACTIVATE the ball and create round surface using the through-hole as reference. The surface sticks out of the ball a bit just so it's easy to create a PROJECTED curve (intersection of the sphere and protruded cylinder).
Then I REDEFINE the ball in assembly and replace TANGENT with point on edge. Additionally I added two-plane constraint to get the FULLY CONSTRAINED condition. It probably creates some circular references somewhere, but at least it's parametric... I hope it makes sense.
 
I do it all the time, it's easy once you figure out how. First I align the axis of the cylinder and the sphere. Then I align "oriented" a datum or plane on each part normal to the axis. This gives you the ability to "flip" the sphere. Without this constraint Pro/E will always do it wrong. Then add a point on a surface constraint. The top edge of the cylinder has two "points" 180 degrees apart that Pro/E will let you pick. Use one of them and the surface of the sphere.
 
dr_gallup said:
I do it all the time, it's easy once you figure out how. First I align the axis of the cylinder and the sphere. Then I align "oriented" a datum or plane on each part normal to the axis. This gives you the ability to "flip" the sphere. Without this constraint Pro/E will always do it wrong. Then add a point on a surface constraint. The top edge of the cylinder has two "points" 180 degrees apart that Pro/E will let you pick. Use one of them and the surface of the sphere.

I tried to do just that... wouldn't let me. That's why I had to add some extra geometry... Weird.

Edited by: marker4x4
 
With "difficult" constraints it often helps - or it is the only possibility ! - to deactivate all constraints and then reactivate them one by one in the correct order.


Correct order : read : the order that ProE likes.


I once constrained a ball onto the top of a spiral spring (modeled to reality with part circular wire and then starting to spiral down) and then had a cilinder with the bottom cut off under an angle sit on top of the ball. "Nice" thing was the spring changed form as it was made adapting to simulate compression.


Alex
 
marker4x4 said:
jabster42 said:
Marker4x4, I'm not exactly sure what you did there. I'm just starting to use WF4.0 (coming from 2001).

I'm using the M020 build.

thanks,
john

First I've assembled temporarily the sphere to the bore using insert and tangent.
It places the ball TANGENT to the btm. of the C/bore. Next I ACTIVATE the ball and create round surface using the through-hole as reference. The surface sticks out of the ball a bit just so it's easy to create a PROJECTED curve (intersection of the sphere and protruded cylinder).
Then I REDEFINE the ball in assembly and replace TANGENT with point on edge. Additionally I added two-plane constraint to get the FULLY CONSTRAINED condition. It probably creates some circular references somewhere, but at least it's parametric... I hope it makes sense.


marker4x4:


ok if you don't mind ending up with circular references?
Edited by: pjw
 

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