Removing area between spokes on a flywheel

michael3424

I need input on how to pattern the cutout on this flywheel so as to make 6 spokes 60° apart.

https://cad.onshape.com/documents/fe2afb5f55cf42489278c204/w/9b61b5b5367d48cb90f9cdf2/e/afb05abda9724f4793070458

I've been approaching this sort of part design roughly the way it would be machined from solid, but perhaps that is not the best way to go with OnShape.  In any case, the area between two adjacent spokes has been Extrude Removed and I was assuming that the extrude cut could be patterned around the rest of the flywheel but that's not working for me.  Am I missing something in patterning a feature around a part, should it be approached differently or is this just not possible in OnShape yet?

Mike

andrew_troup

You could extrude the pie shape as a New Solid, then Circular Pattern it to make six total (parts), then use those parts as tools to subtract from the base part using Boolean
Seems to work OK
https://cad.onshape.com/documents/8ba12d46bf7c4ab097363abf/w/dea81926c8424bf2a3237447

jakeramsley

Michael3424 said:

If OnS is listening, are there any plans to add patterns to sketches?

Yes.  They should be in sooner than later.

andrew_troup

@Michael3424
In this specific scenario, the method I shared is definitely a workaround pending sketch patterns becoming available, but it's a technique which in some contexts would be valuable to know.

BTW, if I modelled the flywheel I would personally use a revolve; that way a single sketch and a single feature would replace your first four of each.

andrew_troup

You could extrude the pie shape as a New Solid, then Circular Pattern it to make six total (parts), then use those parts as tools to subtract from the base part using Boolean
Seems to work OK
https://cad.onshape.com/documents/8ba12d46bf7c4ab097363abf/w/dea81926c8424bf2a3237447

michael3424

That was quick!  Thanks, off to try it now.

Mike

michael3424

Thanks - that worked just fine.  It does seem a little unnatural compared to the way I think such things should be done but it's something that can be adjusted to.  I'm used to either patterning features within a sketch and then extrude cutting the collection or patterning the extrude cut (extrude subtract in OnS).

If OnS is listening, are there any plans to add patterns to sketches?


mike

jakeramsley

Michael3424 said:

If OnS is listening, are there any plans to add patterns to sketches?

Yes.  They should be in sooner than later.

andrew_troup

@Michael3424
In this specific scenario, the method I shared is definitely a workaround pending sketch patterns becoming available, but it's a technique which in some contexts would be valuable to know.

BTW, if I modelled the flywheel I would personally use a revolve; that way a single sketch and a single feature would replace your first four of each.

michael3424

JakeRamsley said:

Yes.  They should be in sooner than later.

Thanks Jake

michael3424

Andrew_Troup said:

@Michael3424
In this specific scenario, the method I shared is definitely a workaround pending sketch patterns becoming available, but it's a technique which in some contexts would be valuable to know.

BTW, if I modelled the flywheel I would personally use a revolve; that way a single sketch and a single feature would replace your first four of each.

Thanks for the suggestion on the revolve.  That part could definitely benefit from a different approach than I used.

Mike

3dcad

You could also use Circular pattern of faces to cut holes on your flywheel. Check this sawblade model https://cad.onshape.com/documents/cc6f7280293e4e6ea020f4ee/w/8525ed8cca38416c9babb2c4

andrew_troup

@3dcad: I tried applying that method to the OP's model prior to making my more primitive (boolean subtraction) suggestion.
It did not work because the faces which need to be patterned are not specific to an individual spoke, but shared; they extend right around the model. This is a limitation of "Face" patterns which I had discovered in another connection and raised a ticket accordingly.