Filleting problems

[Anonymous]

I am having real difficulty with this part.  I need to place a 1/2" fillet between the shrouds and vane (both sides, all of the way around.  I do not have the option of changing the fillet size.  In the areas that there is not enough room for a 1/2" fillet, it still has to have it but it can just be tangent to the surfaces and edge.  This is a real concern since this is a very common type of part for me.  PLEASE HELP.  This seems like such a simple thing to be stuck on for so long.

[WHolzwarth]

I've used Thicken twice, instead of Alias Freeform. Seems to be more stable.

Walter

[Anonymous]

Thanks so much for your help.  I have learned something new.  However, I still cannot get the .5 fillet I need.  Any more suggestions?

[Anonymous]

Well it just seems like you're never going to get that fillet normally since there's simply not enough room on some of those edges. However, if you absolutely had to, you could probably add material in the problem areas so that the fillet will work, then remove the material afterward so that your resulting geometry is the same. I would imagine that you would also need to trim back the fillet a little bit as well in the areas where's there's not 1/2" gap for your fillet in.

That's about all I can think of to make it work:

Add material so the fillet will not fail. Remove added material and extraneous fillet.

Hope this helps.

[Anonymous]

I have added material to the shrout OD's with the intention of removing it later.............Still no go.  Even with plenty of material, it just refuses to fillet.

[JDMather]

I "unmachined" the part removing the hole and extending the flange faces.

I was then able to use Face Fillet to add .5 fillet on one side, but not the other.

So then I opened your original file and started diagnosis.

I edited Sketch1 and noticed missing Tangent Constraints and NO dimensions.

Closed the file.

[Anonymous]

I've been messing with the .ipt a little more. I've found what JD found in sketch1 which is kind of alarming. Though adding the tangent constraints didn't do antyhign fo it. With that said, I tried perfoming your fillet in a piecewise fashion and I think I've found where the problem edges are, but not why they are problem edges. The vertical edge would just need a fillet to work. The horizontal one seems to mainly have problems on the inside of the lofted geometry, not the outside.

I also noticed that you've got a little extra material on the inside of your bottom whateveritscalled.

I've attached images of the problem edges, the extra material, and the area I was able to fillet.

[WHolzwarth]

Well, the Loft should need improvement. See my 2nd attempt.

If EOP is moved up behind Fillet5, a 0.4in fillet can be set at the 2nd set of edges, but no more. The cause is a self intersection at the red spot (Screenshot), if more is wanted.

I've cleaned this region with a boundary patch, but I've ended up with 0.48 in. I think, there's a similar problem at the other red spot.

Walter 

[Anonymous]

Thanks for all of your help.  The sketches are imported from autocad.  I am still kind of green with Inventor but guys like you are helping me along.

Chad

[Anonymous]

yeah you know what might solve everythign is if the loft continues into the top and bottom pieces instead of stopping early where you have to use a secondary feature to continue the shape. I hope that makes sense... but if it were just the loft, you'd have better control of your resulting geometry when it intersects and could more easily ensure that your fillet works. I think the previous response highlights an important thing to know about fillets (that they fail if they self-intersect) and you're getting some strange curvature when the pieces intersect which may be causing your failures but it's difficult to control because of how it is done.

I hope all of that made sense.

[JDMather]

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@Anonymous wrote:

... The sketches are imported from autocad. ..

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I would not use AutoCAD as my sketcher.

The sketches for the loft need to be improved and I wonder where their dimensions came from?

I didn't spend a lot of time since I couldn't follow the logic, but my first thought was, "Can this Loft be improved with better sketches, or what is the intent of the loft?  What is the math behind the shape?  A helix?  Maybe a Sweep path?"

And as indicated by others, it is often better to model the part more like cutting away from a billet or casting when it comes to getting tricky fillets.  And become familiar with the Face Fillet and the Rule Fillets.  Leave the final "machining" to after all the tricky geometry has been solved.

[Anonymous]

Just a little background.  This is a reverse engineered part.  Sketches are measured cross-sections.  It would help for the loft to extend past the shrouds but I dont have measurements of those imaginary points.  Thanks again for everyones help.