topic Re: Creating perfect circular dimple (cut) on a circular surface (ring) in 3D Part & Assembly Design

Creating perfect circular dimple (cut) on a circular surface (ring)

ptc-5136585 — Sun, 13 Dec 2020 11:04:42 GMT

I have a ring and on the surface of that ring I am trying to create a perfect cicle dimple cut. The problem is that since the surface I'm trying to cut into is circular the round dimple turns into an oval. Is there any way to make this feature so that looking down on the ring,

Re: Creating perfect circular dimple (cut) on a circular surface (ring)

TomU — Thu, 06 Jun 2013 12:40:37 GMT

I would think you could do the following:

1.) Extrude a cylindrical surface to represent the outer edge of the dimple that extends through the face of the ring.

2.) Use the intersect feature to create a curve where the cylindrical surface intersects the outside of the ring.

3.) Use the top edge of the surface, the intersect curve, and the center axis of the surface as references for a variable section sweep. Create the dimple surface using a conical shape.

4.) Copy and Move the surface

5.) Pattern as needed

6.) Solidify the initial moved copy

7.) Pattern the solidify

Re: Creating perfect circular dimple (cut) on a circular surface (ring)

ptc-255508 — Thu, 06 Jun 2013 12:40:52 GMT

If its just an aesthetic feature you could;

- profect a circle onto the surface as a guide

- revolve an ellipse which you can then adjust till it matches the circle

- set the revolve axis horizontally in the above image and offset from the surface

Re: Creating perfect circular dimple (cut) on a circular surface (ring)

TomD.inPDX — Thu, 06 Jun 2013 12:47:37 GMT

There are ways but obviously the feature won't be a spherical dimple.

I might try a variable section sweep. you can project a circle onto the surface and use that as a trajectory. Take a look at the arc dropdown in the sketch, you can pick a conic from there for the profile that varies with the sweep, or you could enlist an ellipse.

Re: Creating perfect circular dimple (cut) on a circular surface (ring)

ptc-5136585 — Thu, 06 Jun 2013 12:56:22 GMT

Any way you could show me an example of what you mean?

Re: Creating perfect circular dimple (cut) on a circular surface (ring)

TomD.inPDX — Thu, 06 Jun 2013 13:07:06 GMT

Sure, I will work on one. What version are you using? Academic or full?

Re: Creating perfect circular dimple (cut) on a circular surface (ring)

ptc-5136585 — Thu, 06 Jun 2013 13:10:08 GMT

I'm on full. I'm actually on WF4, but I do have access to Creo pro 5.

Re: Creating perfect circular dimple (cut) on a circular surface (ring)

TomD.inPDX — Thu, 06 Jun 2013 13:18:10 GMT

I am on Creo 2, but the idea is the same. I will make a video and post it later.

The variable section sweep can be a bit tricky. I got it to work but I found a patterning bug I need to report.

Re: Creating perfect circular dimple (cut) on a circular surface (ring)

TomU — Thu, 06 Jun 2013 16:13:23 GMT

I have created a part and uploaded it. You can download it here: http://communities.ptc.com/servlet/JiveServlet/downloadBody/3666-102-1-4658/pattern_dimple.prt.2.zip

You will need to drag the insert arrow back to the bottom of the feature tree. (The filesize is too large if the features are left resumed.)

Re: Creating perfect circular dimple (cut) on a circular surface (ring)

TomU — Thu, 06 Jun 2013 16:15:38 GMT

Screenshot

Re: Creating perfect circular dimple (cut) on a circular surface (ring)

TomD.inPDX — Thu, 06 Jun 2013 16:41:59 GMT

You did pretty much the same as what I came up with. Created a sweep trajectory that helped control the "normal" and the 3D curve as a guide.

I was able to change yours to make that a solid cut. If you pattern that solid cut, it fails... it fails to vary the sweep (the bug I just reported)... but if you use Geometry pattern, it copies the feature faithfully.

I used the axis as a patterning direction. We will see what CS has to say about why the VSS fails patterns.

Re: Creating perfect circular dimple (cut) on a circular surface (ring)

TomD.inPDX — Thu, 06 Jun 2013 16:49:41 GMT

BTW: the file size has an interesting dependency. I learned recently that having high quality graphics levels increases you saved file size. I have 4-5meg files go to 50-100megs just by up'ing all the graphics quality settings (for beauty screenshots). when I save the file, it saves a "graphic rep" of the part in the part file.

I have added the following to config.pro

save_model_display wireframe

...but I don't know yet if this will solve the issue; shaded_lod is default.

Re: Creating perfect circular dimple (cut) on a circular surface (ring)

ptc-5136585 — Thu, 06 Jun 2013 17:31:45 GMT

Wow, it so simple thank you. It was very simple to do but I'm getting some overlap in the bottom of my dimple I'm not quite sure how to remove. I've attached a couple images to show what I mean. Other than that, it looks exactly like what I was anticipating. Thank you very much, (and everybody else) for taking the time to help.

Any idea how to fix this small problem?

Re: Creating perfect circular dimple (cut) on a circular surface (ring)

TomD.inPDX — Thu, 06 Jun 2013 17:42:15 GMT

Yes, you are having a problem with maintaining tangency at the bottom. Variable sections sweeps are a bit fussy about what you use as references.

This is what I ended up with for the section:

The only thing referenced is the two trajectory features and the section's default references. note the vertical constraints to the center of the arc and the implied centerline.

I am working on uploading a video to youtube on this (although in Creo 2)

Re: Creating perfect circular dimple (cut) on a circular surface (ring)

TomD.inPDX — Thu, 06 Jun 2013 17:47:13 GMT

The video!

remember to use full screen and set to HD

edit: Creo 2 part attached.

Re: Creating perfect circular dimple (cut) on a circular surface (ring)

TomU — Thu, 06 Jun 2013 17:49:23 GMT

I just figured out a better way to pattern this.

1.) Do a move copy by axis on the first surface by 20 degrees.

2.) Pattern this move copy 18 times. This creates the bottom row.

3.) Solidify (cut) the first suface.

4.) Pattern this solidify (reference pattern)

5.) Group the move copy pattern and the solidfy pattern.

6.) Do a move copy on this group two directions - .25" up and 10 degrees around.

7.) Pattern this latest move copy. Use both the .25" and the 10 degree dimensions for the 1st direction references.

Re: Creating perfect circular dimple (cut) on a circular surface (ring)

TomU — Thu, 06 Jun 2013 17:54:12 GMT

Not sure what your sketch looks like, but I'm making my arc (variable radius) perpendicular to the axis.

Re: Creating perfect circular dimple (cut) on a circular surface (ring)

TomU — Thu, 06 Jun 2013 17:55:11 GMT

I think we're chasing each other's tails. 🙂

Re: Creating perfect circular dimple (cut) on a circular surface (ring)

ptc-5136585 — Thu, 06 Jun 2013 18:02:46 GMT

I wonder if that's my problem my radius is fixed. It is indeed perpendicular to the axis though which I would think would eliminate the problem.

Re: Creating perfect circular dimple (cut) on a circular surface (ring)

ptc-5136585 — Thu, 06 Jun 2013 18:03:19 GMT

Man this is fabulous, if only I had something to reward you two with.