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ptc-30553611-Visitor
1-Visitor
January 10, 2014
Question

Modeling problem

  • January 10, 2014
  • 3 replies
  • 2486 views

I am working on a turbine nozzle/vane in Wildfire 4.0 and I need to generate an elliptical radius between the airfoil solid geometry and the adjacent platform. What is the best surfacing option for this application? The elliptical radius radically changes value around the airfoil. Please help.

George

3 replies

T
TomD.inPDX17-Peridot
17-Peridot
January 10, 2014

If I am understanding you correctly, George, you might consider a variable section sweep using the ellipse.

I am not sure if there are features not implemented in WF4 that now exist in Creo with regard to Round features.

You do have Sweep/Blend options in WF4.

Feel free to post some screen shots of the challenge you are working with.

And welcome to the forum.

C
Constantin15-Moonstone
15-Moonstone
January 13, 2014

You could also use a 'conic round' (inside the round feature).
The 'conic' parameter allows you to control its form.
You can add radius points in order to make it variable as well.

conic_round.jpg

conic_2.jpg

P
ptc-30553611-VisitorAuthor
1-Visitor
January 13, 2014

Thank you for your responses. Unfortunately, I have tried both options before and it does not provide me the correct results. The elliptical surfaces that I need to generate have a lot of curvature change as I go around the airfoil. So far, I have been using boundary blends. I generate a number of sketches around the airfoil and making sure that it is tangent to both surfaces. This method has captured what I needed, unfortunately majority of the times, Pro-E would cannot create the feature. I need another option that would allow me to use sketches around the airfoil and produce a surface tangent to both airfoil and platform. Thank you.

T
TomD.inPDX17-Peridot
17-Peridot
January 13, 2014

Creo can be very touchy about sketched ellipses. They don't always update correctly once you trim them as an open curve.

The other option is a variable section sweep. This means you can, and must fully define the tangency on both ends and an offset for the tangency to provide the sketch orientation. With a robust series of sketches, this feature will remain more stable and likely more consistent.

I can see how this can be challenging. I don't know if there is a "best way" to do this. If it was a simple round, you would have more options.

I might even go so far as to define 2 round or a single D1xD2 fillet as a surface and using the edges for the VSS. In reality, maintaining tangency is the larger part of the issue. The "normal" along the surface round edges should follow a tangency for a subsequent sweep but I am not sure if you can maintain that on both edges since the second is only a guide curve. But if the platform is flat, this may not matter.

Again, I am not picturing the full scope of the feature so it is harder to know exactly what you are facing.

P
ptc-48904521-Visitor
1-Visitor
January 13, 2014

Hi George.

Can you share your file or some screenshots?

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