sketching or sweep/revolve on cylindrical surface

[mbostonsprint]

I'm a bit stuck on how to create geometry on a cylindrical surface with the end goal being to have multiple slots following a circumferential path around the surface of a tube, and through the thickness of the wall. I had thought that punching a hole through the tube wall would lead me to some path such that the hole could be swept or revolved around the tube axis, but that doesn't seem possible. The "Slot" option in sketch can't be used since the surface isn't flat (at least I don't know how if that is possible). I created a couple of construction planes tangent to the holes I have in the model, with the idea of removing the material in the selected areas between hole pairs, but that doesn't seem to work either. I'm likely missing something in that case in terms of command sequence.

Anyone out there with a suggestion or solution? Thanks --

[carl_bass]

Is this something like what you want?

What size and orientation do you want the slots?

[mbostonsprint]

Happy Thanksgiving (I guess)!

No, the slots need to be oriented to follow a circumferential path, 90 degrees to the direction you show. The holes I have in the end of the tube essentially indicate the end points of each of 4 slots, 1 hole pair per slot. Thanks for any additional info you can provide. 

Matt

[haughec · Accepted solution]

Happy Thanksgiving, Matt!

I think that I've created the slots you're looking for.  I created a single slot by constructing two holes 45 degrees apart, and then connecting them with a revolved cut.  I then patterned that slot around the Y axis to create the remaining three.  Below is an image.  I'll post the model as well.

Charles

[haughec]

Model attached.

Charles

[haughec · Accepted solution]

Ok, one more proposal from a retentive modeler...  Attached is another approach that is a bit simpler and more robust.  Start by creating a revolved cut (as shown in the first image), and then just fillet the corners of the slot with a radius equal to 1/2 of the slot width to create a nice, round end.  You can then pattern the Revolve & Fillet features to craete the remaining slots.

 Revolved Cut:

Fillet:

Hope this helps,

Charles

[mbostonsprint]

Thanks for the info on holiday -- much appreciated. So it does appear that there is a method using a revolve command. This is what I initially thought, but the detailed mechanics seem to be a bit opaque. I'll look a little harder at the command and go from there.

Matt

[mbostonsprint]

I succeeded in using the cut/revolve approach to get what I needed. It seems that this could be made much less cumbersome if one were able to use the "Hole" feature as the cutting tool, essentially the same concept as machining the slot with an endmill. Thanks again for the assistance --

Matt

[mbostonsprint]

This is a bit of continuation of the previous discussion. I am attaching a revised model, done in Direct (non-parametric?) modeling and have a few questions:

The construction plane that is shown is meant to assist in locating the cuts that I would make to revolve to create the slots circumferentially in the tube wall. The plane is created using the "two-edge" option, using the small line across one hole, and the center axis through the tube, then extended as needed.

In trying to make what I need, I have run into several things which I see as odd.

-When I start a sketch to draw lines on the construction plane, I select the plane, and the plane turns itself off as the model automatically orients the construction plane to "face" view. Why does that occur? I do now see that it can be turned on again in the browser, but it seems strange to turn the selected plane off as part of the ongoing command syntax.

-I note that the holes (4 places) I have placed through the tube wall are by default positioned across the diameter of the tube, which is good as a known behavior. What I don't yet understand is a.) why the holes show a selectable vertex (180-degree split) on the outside surface of the tube, but a continuous edge on the inside surface, and b.) why I cannot place a construction point at the intersection of the hole edge and the construction plane on the inside diameter. When I read the context description with the command, I see that this apparently only applies to linear edge and plane intersections, but it seems like an arbitrary limitation.

-Last, if you can provide a workflow/command sequence for creating and locating per dimension the cuts as you see them best done, that would be useful. Conceptually it is easy, but the actual mechanics seem more complicated than I would have thought.