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edge on rounded blade tip

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awwolfe

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Sep 28, 2009
5
sw2009. Trying to put a 30 degree (each edge -- 60 degree edge total)rounded (partial parabola) on the tip of blade (0.5625" wide, 0.125" thick -- at tip) with a partial parabola of 1".

How do I accomplish this without errors? Sweeping 1/2 profile gives overlap errors because partial parabola too sharp. Unable to loft up-- can't make partial parabolas on 3d plane (why not????)....Tried cutting away as well, but again had overlap errors. Seems crazy, this shouldn't be this difficult.

thanks,

Tony
 
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Hi Tony,

I extruded your outline shape (half ellipse and straight edges), then used 30/60 degree chamfers that I calculate. You could drive these from a formula based on blade thickness. I then extruded your blade profile as a cut. I wasn't sure how you wanted the blade to terminate.

Hope this at least gives you some ideas.

 
 http://files.engineering.com/getfile.aspx?folder=08f9275b-d43e-4101-b2f0-68fd6a7a027c&file=test_tip_shape.SLDPRT
IanLougheed,

Seriously thanks for the quick response and help. I did try the chamfer as well, but again was unable to get the full angle without an error. After looking at your drawing, I realized that (after a really long day), I made a mistake in my sample drawing (although correct in my description). The entire width is only 0.5625 (as described), but I made it twice that (1.125) in the sample file. I apologize for wasting your time trying to solve a problem that wasn't accurately shown in the file.

If you don't mind looking at the correct one (hopefully) I'd extremely appreciate it. I don't see any reason why the program fails in this.

Tony
 
 http://files.engineering.com/getfile.aspx?folder=d71c3b57-8ef8-429b-9dbd-797585820eed&file=test_tip_shape_proper_width.SLDPRT
Surfacing tools are your friend here.

If I thought about it a bit more I am sure it could probably be created a bit more efficiently.

This should give you some ideas if I am interpreting what you want correctly.

Cheers,



Anna Wood
Anna Built Workstation, Core i7 EE965, FirePro V8700, 12 gigs of RAM, OCZ Vertex 120 Gig SSD
SW2009 SP3.0, Windows 7 RC1
 
AnnaWood,

Wow, thanks. The file you used was at the wrong width (see my second post), however, when I resized it to correct width (in half), it still WORKED!. I am not all that familiar with the tools you used, but I'm spending the day studying your sample and learning it!

Thanks again,

Tony

again, not sure why the chamfer or other tools fail when the angle gets too steep.
 
AnnaWood,

This is going to be a total Newbie question, but for your Sketch 5, you created a sketch plane that was offset from the center top plane without it being a 3d sketch. This enables you to use the partial parabola function (which doesn't seem to work for 3d sketches).

I can not figure out how to create a sketch plane that is offset from the center top plane as you did.

Can you explain how this is done? Or provide a reference link for me please?

Many thanks again,

Tony
 
AnnaWood,

Never mind, I finally figured it out....


THANKS AGAIN FOR YOUR HELP AND YOUR SOLUTION!!!!!!!!!!

Tony
 
Tony,

I think Anna's solution is the better one, and will be more flexible when you wish to model increasingly complex blade shapes. In fact I'll be looking at her solution to learn more about surfacing.

Take care.
 
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