Problem with a Loft

[rmoore]

I have a casting that starts out with a 100mm diameter that bends around a 90mm radius and blends in with a vertical flange that was extruded with a 3 deg taper. The problem I'm having is that the blend follows more then one profile. (See attached jpg)

When I attempt to do a loft, using two rails to define the profiles, I get the attached error. I've identified the top rail as the problem maker but I'm not sure how to resolve the issue. I've checked to make sure that the rail starts at the upper quadrant of the 100mm circle and that the point where the tapered flange leg meets the radius is tangent.

Any advice I can get to help me resolve this would be greatly appreciated.

Thanks,

[jonathan.landeros]

I have a casting that starts out with a 100mm diameter that bends around a 90mm radius and blends in with a vertical flange that was extruded with a 3 deg taper. The problem I'm having is that the blend follows more then one profile. (See attached jpg)

When I attempt to do a loft, using two rails to define the profiles, I get the attached error. I've identified the top rail as the problem maker but I'm not sure how to resolve the issue. I've checked to make sure that the rail starts at the upper quadrant of the 100mm circle and that the point where the tapered flange leg meets the radius is tangent.

Any advice I can get to help me resolve this would be greatly appreciated.

Thanks,Are the rails on two separate sketches? I know that if you place the rails on the same sketch, Inventor thinks it's one broken rail and gets grumpy.

That's one of the easiest things to make a mistake on. ( do it all the time).

[rmoore]

The rails are each a separate sketch so that shouldn't be the issue. Thanks for the quick response though!

[chadwickt]

Can you post a copy of the part file?

[rmoore]

chadwickt,

No problem, here is the prt file I've been working on.

Thanks,

[JD Mather]

Something like this? Pull down the red End of Part (EOP) marker in the browser.
You can get the file here -
http://discussion.autodesk.com/thread.jspa?threadID=457928


http://home.pct.edu/~jmather/content/DSG322/inventor_surface_tutorials.htm

[rmoore]

Something like this? Pull down the red End of Part (EOP) marker in the browser.
You can get the file here -
http://discussion.autodesk.com/thread.jspa?threadID=457928


http://home.pct.edu/~jmather/content/DSG322/inventor_surface_tutorials.htm
Yes that works. But I'm not clear on why yours does and mine doesn't. Can you elaborate further on your method.

Thanks,

[JD Mather]

The large radius rail was not attached to the large circle section. In general you should create rails after sections (or simplify as I did and attach to part edge).
I consider my first attempt to be a trial just to understand the geometry - I almost always model something like this two or three times till I get a robust model.
I assume you don't really want that block you mirrored to go through the hole? In the first part I posted simply drag Hole1 down to the end of the history tree if you don't want the block going through it like you had in your attachment. My second post was simply some fooling around. I would be curious to see your finished part.