Autodesk Inventor

[#1]

Hello all,

I'm using Inventor Professional 2012.  I have what seems like a relatively simple part, but I cannot find any way to apply a face draft to the four quadrants between the upper outer and inner "'cylinders".  I get the dreaded "did not produce a meaningful result. Try with different inputs." no matter which type of draft I try.  I have created parting line drafts everywhere else.  Can anyone please tell me how I can get these faces to draft?  I'm also open to any suggestions on how to draw this better.

I've zipped up my IPT.  I appreciate any help at all.

-Russ

[#2]

First thing I notice is that your Main Sketch is not fully constrained - missing 13 dimensions or constraints.

You might read this document http://home.pct.edu/~jmather/skillsusa%20university.pdf

Did you intend for these arcs to be tangent?

I think you can get most of the Face Draft in the first extrusion if you set it up correctly.

I'll try to post an example in a while.

[#3]

Thanks for the reference to your excellent document.  I'll use it for sure.  Yes, I did intend tangency there.  I drew the upper arcs as circles (then later trimmed) but I could not manage to get the lower arcs tangent the way I wanted.

I have tended to ignore the missing constraings sometimes because it adds dimensions that seem irrelevant to me (like lenghts of construction lines), clogging up the drawing.  Your comments indicate that's wrong, and I need to seek fully constrained sketches.

I look forward to your example, because all those separate face drafts seemed like they should be unnecessary.

-Russ

[#4 · Accepted solution]

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russ wrote:

...clogging up the drawing. 

 -Russ

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Edit my sketches (see attached) they don't look clogged up to me?

My sketch is fully constrained.

[#5]

Wow!  All I can say is "man, you're good!"    I'm looking over your drawing and saying things like "You can do that?" and "I never would have thought of that!"  Extruding with a taper and mirroring it is so much simpler than a parting line draft.  Plus, I can add fillets to all the edges, something I couldn't do with my drawing no matter how hard I tried.  But I don't think I understand the purpose of the Replace Face at the end.

I cannot thank you enough, especially for demonstrating how elegant Inventor can be when used correctly.

-Russ

[#6]

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russ wrote:

  But I don't think I understand the purpose of the Replace Face at the end.

 -Russ

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Drag the red End of Part marker at the bottom of the feature tree to just above the Replace Face feature.

Examine the bottom of the part.  Notice that there is a draft angle on the bottom.  I assumed you wanted this face to be flat.  The Replace Face accomplishes this.  If you do not want it flat then delete the Replace Face feature.

[#7]

I suspected that was the purpose.  I would indeed prefer the bottom to be flat, but I'm pretty sure the injection molding folks are going to require a face draft of at least 1/2 degree anyway.

Again, thank you so much for the lesson on doing it right.  I'll be referring to that sketch often, I'm sure.

-Russ

[#8]

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russ wrote:

 the injection molding folks are going to require a face draft of at least 1/2 degree anyway.

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See attached if different draft on the bottom than rest of part - otherwise just change the original DraftAngle variable.

[#9]

Thanks so much for the follow-up.

I'm staring at your sketch, and you've somehow managed to describe a pretty complex shape with just seven dimensions (and lots of constraints)!  I don't know how you did it.  For example, you have constrained the two middle circles to the proper offsets without dimensioning them.  I don't understand how that's possible.  I'm feeling pretty ignorant.  

-Russ

[#10]

Actually if I were doing it over again I think I could improve a bit more.
Edit the sketch and right click and select Show all Constraints.

You will see a bunch of equal (=) constraints that I used on small construction lines.

I will try to attach an improved example tomorrow.