Is there a way to profile a cut on a sphere surface

Question

I'm stumped, been trying to do this for 2 weeks now, think I'll go bald before I figure it out so I'm asking the experts, it's got me beat and I'm fast running out of time.

Here's the problem, I have a 100mm dia sphere and I want to machine a figure of 8 track on the surface, say the track is 12mm wide x 6mm deep along the centre line of the cut, the centre line of the "8" extends 45degrees across the surface with a radius of say 12.5mm around the bends. The problem I can't figure out is at any point of the centre axis of the cut must intersect the centre point of the sphere ant the walls of the cut must be parallel to this (think of it as a surface slot for a follower guide). I've tried everthing I can think of, lofts, surface intersections, 3D cut's but I can't get it, I'm thinking that SW can't do this, is it possible?

You help will be very very much appreciated.

Thanks in advance. Brian

mjlombard · Accepted Answer

There are several ways to do this, here is just one.

baron · Answer

I have similar problem. Can't figure out how to make side walls of thecut paralel to center axis of the cut.

CS · Answer

Have you tried a wrap Insert>Features>Wrap

Paul Salvador · Answer

FYI, modified your cut using a surface offset, lofts and knit to do asurface cut and found a glitch with SW.(btw, it works fine if you make a solid out of the knit and do asubtract)

CS · Answer

Paul the surface cut will work if you open the top face and extend theedges beyond the top surface of the sphere. I could send you the modelif you like.Regards,Corey Scheich

CS · Answer

This is probably due to surface tollerancing.

Paul Salvador · Answer

Cory,But, it does extend beyond the spherical surface by .01".The magical number for it to resolve properly is .0212"?Obviously a issue of tolerance the program (or Parasolid) has set forthis result?Funny though, why the user should have to full around with workaroundsfor something so basic?Qaulity control at SW Corp!?!?!?!??!!!?!?!?Things that make you go,... hmm.......and, oh boy, now that's confidencereinforcement!?..

Paul Salvador · Answer

correction,.. it's about 0.0211694575" for it to resolve!?!?!?!So much fun...

Seth Renigar · Answer

What's even more fun is that it DOES work, just as you have it posted! Huh?!?! Well sort-of anyway...

Try this. Open the file just as you have it posted. Don't do anything in the feature tree. Go to your document properties and change the image quality to maximum. Walla!!! There is the feature you were looking for,,,, graphically anyway. It seems that you can't "directly" select this feature in the graphics window, or any other feature for that matter. You can however right click>select other, to select the features. Its almost like there is an transparent spherical surface around the whole part that prevents you from selecting anything by clicking on it.

Once you change the offset to your "magic" number, the feature then become directly selectable in the graphics window.

This IS strange...

Is there a way to profile a cut on a sphere surface

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